This is the thirteenth edition of the `GNU Emacs Manual', updated for
Emacs version 20.7.
Published by the Free Software Foundation 59 Temple Place, Suite 330
Boston, MA 02111-1307 USA
Copyright (C) 1985, 1986, 1987, 1993, 1994, 1995, 1996, 1997, 1998,
1999 Free Software Foundation, Inc.
Permission is granted to make and distribute verbatim copies of this
manual provided the copyright notice and this permission notice are
preserved on all copies.
Permission is granted to copy and distribute modified versions of
this manual under the conditions for verbatim copying, provided also
that the sections entitled "The GNU Manifesto", "Distribution" and "GNU
General Public License" are included exactly as in the original, and
provided that the entire resulting derived work is distributed under the
terms of a permission notice identical to this one.
Permission is granted to copy and distribute translations of this
manual into another language, under the above conditions for modified
versions, except that the sections entitled "The GNU Manifesto",
"Distribution" and "GNU General Public License" may be included in a
translation approved by the Free Software Foundation instead of in the
original English.
The Emacs Editor
****************
Emacs is the extensible, customizable, self-documenting real-time
display editor. This Info file describes how to edit with Emacs and
some of how to customize it; it corresponds to GNU Emacs version 20.7.
For information on extending Emacs, see *Note Emacs Lisp: (elisp).
Distribution
************
GNU Emacs is "free software"; this means that everyone is free to
use it and free to redistribute it on certain conditions. GNU Emacs is
not in the public domain; it is copyrighted and there are restrictions
on its distribution, but these restrictions are designed to permit
everything that a good cooperating citizen would want to do. What is
not allowed is to try to prevent others from further sharing any version
of GNU Emacs that they might get from you. The precise conditions are
found in the GNU General Public License that comes with Emacs and also
appears following this section.
One way to get a copy of GNU Emacs is from someone else who has it.
You need not ask for our permission to do so, or tell any one else; just
copy it. If you have access to the Internet, you can get the latest
distribution version of GNU Emacs by anonymous FTP; see the file
`etc/FTP' in the Emacs distribution for more information.
You may also receive GNU Emacs when you buy a computer. Computer
manufacturers are free to distribute copies on the same terms that
apply to everyone else. These terms require them to give you the full
sources, including whatever changes they may have made, and to permit
you to redistribute the GNU Emacs received from them under the usual
terms of the General Public License. In other words, the program must
be free for you when you get it, not just free for the manufacturer.
You can also order copies of GNU Emacs from the Free Software
Foundation on CD-ROM. This is a convenient and reliable way to get a
copy; it is also a good way to help fund our work. (The Foundation has
always received most of its funds in this way.) An order form is
included in the file `etc/ORDERS' in the Emacs distribution, and on our
web site in `http://www.gnu.org/order/order.html'. For further
information, write to
Free Software Foundation
59 Temple Place, Suite 330
Boston, MA 02111-1307 USA
USA
The income from distribution fees goes to support the foundation's
purpose: the development of new free software, and improvements to our
existing programs including GNU Emacs.
If you find GNU Emacs useful, please *send a donation* to the Free
Software Foundation to support our work. Donations to the Free
Software Foundation are tax deductible in the US. If you use GNU Emacs
at your workplace, please suggest that the company make a donation. If
company policy is unsympathetic to the idea of donating to charity, you
might instead suggest ordering a CD-ROM from the Foundation
occasionally, or subscribing to periodic updates.
GNU GENERAL PUBLIC LICENSE
**************************
Version 2, June 1991
Copyright (C) 1989, 1991 Free Software Foundation, Inc.
59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
Everyone is permitted to copy and distribute verbatim copies
of this license document, but changing it is not allowed.
Preamble
========
The licenses for most software are designed to take away your
freedom to share and change it. By contrast, the GNU General Public
License is intended to guarantee your freedom to share and change free
software--to make sure the software is free for all its users. This
General Public License applies to most of the Free Software
Foundation's software and to any other program whose authors commit to
using it. (Some other Free Software Foundation software is covered by
the GNU Library General Public License instead.) You can apply it to
your programs, too.
When we speak of free software, we are referring to freedom, not
price. Our General Public Licenses are designed to make sure that you
have the freedom to distribute copies of free software (and charge for
this service if you wish), that you receive source code or can get it
if you want it, that you can change the software or use pieces of it in
new free programs; and that you know you can do these things.
To protect your rights, we need to make restrictions that forbid
anyone to deny you these rights or to ask you to surrender the rights.
These restrictions translate to certain responsibilities for you if you
distribute copies of the software, or if you modify it.
For example, if you distribute copies of such a program, whether
gratis or for a fee, you must give the recipients all the rights that
you have. You must make sure that they, too, receive or can get the
source code. And you must show them these terms so they know their
rights.
We protect your rights with two steps: (1) copyright the software,
and (2) offer you this license which gives you legal permission to copy,
distribute and/or modify the software.
Also, for each author's protection and ours, we want to make certain
that everyone understands that there is no warranty for this free
software. If the software is modified by someone else and passed on, we
want its recipients to know that what they have is not the original, so
that any problems introduced by others will not reflect on the original
authors' reputations.
Finally, any free program is threatened constantly by software
patents. We wish to avoid the danger that redistributors of a free
program will individually obtain patent licenses, in effect making the
program proprietary. To prevent this, we have made it clear that any
patent must be licensed for everyone's free use or not licensed at all.
The precise terms and conditions for copying, distribution and
modification follow.
TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION
0. This License applies to any program or other work which contains a
notice placed by the copyright holder saying it may be distributed
under the terms of this General Public License. The "Program",
below, refers to any such program or work, and a "work based on
the Program" means either the Program or any derivative work under
copyright law: that is to say, a work containing the Program or a
portion of it, either verbatim or with modifications and/or
translated into another language. (Hereinafter, translation is
included without limitation in the term "modification".) Each
licensee is addressed as "you".
Activities other than copying, distribution and modification are
not covered by this License; they are outside its scope. The act
of running the Program is not restricted, and the output from the
Program is covered only if its contents constitute a work based on
the Program (independent of having been made by running the
Program). Whether that is true depends on what the Program does.
1. You may copy and distribute verbatim copies of the Program's
source code as you receive it, in any medium, provided that you
conspicuously and appropriately publish on each copy an appropriate
copyright notice and disclaimer of warranty; keep intact all the
notices that refer to this License and to the absence of any
warranty; and give any other recipients of the Program a copy of
this License along with the Program.
You may charge a fee for the physical act of transferring a copy,
and you may at your option offer warranty protection in exchange
for a fee.
2. You may modify your copy or copies of the Program or any portion
of it, thus forming a work based on the Program, and copy and
distribute such modifications or work under the terms of Section 1
above, provided that you also meet all of these conditions:
a. You must cause the modified files to carry prominent notices
stating that you changed the files and the date of any change.
b. You must cause any work that you distribute or publish, that
in whole or in part contains or is derived from the Program
or any part thereof, to be licensed as a whole at no charge
to all third parties under the terms of this License.
c. If the modified program normally reads commands interactively
when run, you must cause it, when started running for such
interactive use in the most ordinary way, to print or display
an announcement including an appropriate copyright notice and
a notice that there is no warranty (or else, saying that you
provide a warranty) and that users may redistribute the
program under these conditions, and telling the user how to
view a copy of this License. (Exception: if the Program
itself is interactive but does not normally print such an
announcement, your work based on the Program is not required
to print an announcement.)
These requirements apply to the modified work as a whole. If
identifiable sections of that work are not derived from the
Program, and can be reasonably considered independent and separate
works in themselves, then this License, and its terms, do not
apply to those sections when you distribute them as separate
works. But when you distribute the same sections as part of a
whole which is a work based on the Program, the distribution of
the whole must be on the terms of this License, whose permissions
for other licensees extend to the entire whole, and thus to each
and every part regardless of who wrote it.
Thus, it is not the intent of this section to claim rights or
contest your rights to work written entirely by you; rather, the
intent is to exercise the right to control the distribution of
derivative or collective works based on the Program.
In addition, mere aggregation of another work not based on the
Program with the Program (or with a work based on the Program) on
a volume of a storage or distribution medium does not bring the
other work under the scope of this License.
3. You may copy and distribute the Program (or a work based on it,
under Section 2) in object code or executable form under the terms
of Sections 1 and 2 above provided that you also do one of the
following:
a. Accompany it with the complete corresponding machine-readable
source code, which must be distributed under the terms of
Sections 1 and 2 above on a medium customarily used for
software interchange; or,
b. Accompany it with a written offer, valid for at least three
years, to give any third party, for a charge no more than your
cost of physically performing source distribution, a complete
machine-readable copy of the corresponding source code, to be
distributed under the terms of Sections 1 and 2 above on a
medium customarily used for software interchange; or,
c. Accompany it with the information you received as to the offer
to distribute corresponding source code. (This alternative is
allowed only for noncommercial distribution and only if you
received the program in object code or executable form with
such an offer, in accord with Subsection b above.)
The source code for a work means the preferred form of the work for
making modifications to it. For an executable work, complete
source code means all the source code for all modules it contains,
plus any associated interface definition files, plus the scripts
used to control compilation and installation of the executable.
However, as a special exception, the source code distributed need
not include anything that is normally distributed (in either
source or binary form) with the major components (compiler,
kernel, and so on) of the operating system on which the executable
runs, unless that component itself accompanies the executable.
If distribution of executable or object code is made by offering
access to copy from a designated place, then offering equivalent
access to copy the source code from the same place counts as
distribution of the source code, even though third parties are not
compelled to copy the source along with the object code.
4. You may not copy, modify, sublicense, or distribute the Program
except as expressly provided under this License. Any attempt
otherwise to copy, modify, sublicense or distribute the Program is
void, and will automatically terminate your rights under this
License. However, parties who have received copies, or rights,
from you under this License will not have their licenses
terminated so long as such parties remain in full compliance.
5. You are not required to accept this License, since you have not
signed it. However, nothing else grants you permission to modify
or distribute the Program or its derivative works. These actions
are prohibited by law if you do not accept this License.
Therefore, by modifying or distributing the Program (or any work
based on the Program), you indicate your acceptance of this
License to do so, and all its terms and conditions for copying,
distributing or modifying the Program or works based on it.
6. Each time you redistribute the Program (or any work based on the
Program), the recipient automatically receives a license from the
original licensor to copy, distribute or modify the Program
subject to these terms and conditions. You may not impose any
further restrictions on the recipients' exercise of the rights
granted herein. You are not responsible for enforcing compliance
by third parties to this License.
7. If, as a consequence of a court judgment or allegation of patent
infringement or for any other reason (not limited to patent
issues), conditions are imposed on you (whether by court order,
agreement or otherwise) that contradict the conditions of this
License, they do not excuse you from the conditions of this
License. If you cannot distribute so as to satisfy simultaneously
your obligations under this License and any other pertinent
obligations, then as a consequence you may not distribute the
Program at all. For example, if a patent license would not permit
royalty-free redistribution of the Program by all those who
receive copies directly or indirectly through you, then the only
way you could satisfy both it and this License would be to refrain
entirely from distribution of the Program.
If any portion of this section is held invalid or unenforceable
under any particular circumstance, the balance of the section is
intended to apply and the section as a whole is intended to apply
in other circumstances.
It is not the purpose of this section to induce you to infringe any
patents or other property right claims or to contest validity of
any such claims; this section has the sole purpose of protecting
the integrity of the free software distribution system, which is
implemented by public license practices. Many people have made
generous contributions to the wide range of software distributed
through that system in reliance on consistent application of that
system; it is up to the author/donor to decide if he or she is
willing to distribute software through any other system and a
licensee cannot impose that choice.
This section is intended to make thoroughly clear what is believed
to be a consequence of the rest of this License.
8. If the distribution and/or use of the Program is restricted in
certain countries either by patents or by copyrighted interfaces,
the original copyright holder who places the Program under this
License may add an explicit geographical distribution limitation
excluding those countries, so that distribution is permitted only
in or among countries not thus excluded. In such case, this
License incorporates the limitation as if written in the body of
this License.
9. The Free Software Foundation may publish revised and/or new
versions of the General Public License from time to time. Such
new versions will be similar in spirit to the present version, but
may differ in detail to address new problems or concerns.
Each version is given a distinguishing version number. If the
Program specifies a version number of this License which applies
to it and "any later version", you have the option of following
the terms and conditions either of that version or of any later
version published by the Free Software Foundation. If the Program
does not specify a version number of this License, you may choose
any version ever published by the Free Software Foundation.
10. If you wish to incorporate parts of the Program into other free
programs whose distribution conditions are different, write to the
author to ask for permission. For software which is copyrighted
by the Free Software Foundation, write to the Free Software
Foundation; we sometimes make exceptions for this. Our decision
will be guided by the two goals of preserving the free status of
all derivatives of our free software and of promoting the sharing
and reuse of software generally.
NO WARRANTY
11. BECAUSE THE PROGRAM IS LICENSED FREE OF CHARGE, THERE IS NO
WARRANTY FOR THE PROGRAM, TO THE EXTENT PERMITTED BY APPLICABLE
LAW. EXCEPT WHEN OTHERWISE STATED IN WRITING THE COPYRIGHT
HOLDERS AND/OR OTHER PARTIES PROVIDE THE PROGRAM "AS IS" WITHOUT
WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, BUT
NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
FITNESS FOR A PARTICULAR PURPOSE. THE ENTIRE RISK AS TO THE
QUALITY AND PERFORMANCE OF THE PROGRAM IS WITH YOU. SHOULD THE
PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL NECESSARY
SERVICING, REPAIR OR CORRECTION.
12. IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN
WRITING WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MAY
MODIFY AND/OR REDISTRIBUTE THE PROGRAM AS PERMITTED ABOVE, BE
LIABLE TO YOU FOR DAMAGES, INCLUDING ANY GENERAL, SPECIAL,
INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE USE OR
INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED TO LOSS OF
DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU
OR THIRD PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY
OTHER PROGRAMS), EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN
ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.
END OF TERMS AND CONDITIONS
How to Apply These Terms to Your New Programs
=============================================
If you develop a new program, and you want it to be of the greatest
possible use to the public, the best way to achieve this is to make it
free software which everyone can redistribute and change under these
terms.
To do so, attach the following notices to the program. It is safest
to attach them to the start of each source file to most effectively
convey the exclusion of warranty; and each file should have at least
the "copyright" line and a pointer to where the full notice is found.
ONE LINE TO GIVE THE PROGRAM'S NAME AND AN IDEA OF WHAT IT DOES.
Copyright (C) 19YY NAME OF AUTHOR
This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License
as published by the Free Software Foundation; either version 2
of the License, or (at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License along
with this program; if not, write to the Free Software Foundation, Inc.,
59 Temple Place, Suite 330, Boston, MA 02111-1307, USA.
Also add information on how to contact you by electronic and paper
mail.
If the program is interactive, make it output a short notice like
this when it starts in an interactive mode:
Gnomovision version 69, Copyright (C) 19YY NAME OF AUTHOR
Gnomovision comes with ABSOLUTELY NO WARRANTY; for details
type `show w'. This is free software, and you are welcome
to redistribute it under certain conditions; type `show c'
for details.
The hypothetical commands `show w' and `show c' should show the
appropriate parts of the General Public License. Of course, the
commands you use may be called something other than `show w' and `show
c'; they could even be mouse-clicks or menu items--whatever suits your
program.
You should also get your employer (if you work as a programmer) or
your school, if any, to sign a "copyright disclaimer" for the program,
if necessary. Here is a sample; alter the names:
Yoyodyne, Inc., hereby disclaims all copyright
interest in the program `Gnomovision'
(which makes passes at compilers) written
by James Hacker.
SIGNATURE OF TY COON, 1 April 1989
Ty Coon, President of Vice
This General Public License does not permit incorporating your
program into proprietary programs. If your program is a subroutine
library, you may consider it more useful to permit linking proprietary
applications with the library. If this is what you want to do, use the
GNU Library General Public License instead of this License.
Introduction
************
You are reading about GNU Emacs, the GNU incarnation of the advanced,
self-documenting, customizable, extensible real-time display editor
Emacs. (The `G' in `GNU' is not silent.)
We say that Emacs is a "display" editor because normally the text
being edited is visible on the screen and is updated automatically as
you type your commands. *Note Display: Screen.
We call it a "real-time" editor because the display is updated very
frequently, usually after each character or pair of characters you
type. This minimizes the amount of information you must keep in your
head as you edit. *Note Real-time: Basic.
We call Emacs advanced because it provides facilities that go beyond
simple insertion and deletion: controlling subprocesses; automatic
indentation of programs; viewing two or more files at once; editing
formatted text; and dealing in terms of characters, words, lines,
sentences, paragraphs, and pages, as well as expressions and comments in
several different programming languages.
"Self-documenting" means that at any time you can type a special
character, `Control-h', to find out what your options are. You can
also use it to find out what any command does, or to find all the
commands that pertain to a topic. *Note Help::.
"Customizable" means that you can change the definitions of Emacs
commands in little ways. For example, if you use a programming
language in which comments start with `<**' and end with `**>', you can
tell the Emacs comment manipulation commands to use those strings
(*note Comments::.). Another sort of customization is rearrangement of
the command set. For example, if you prefer the four basic cursor
motion commands (up, down, left and right) on keys in a diamond pattern
on the keyboard, you can rebind the keys that way. *Note
Customization::.
"Extensible" means that you can go beyond simple customization and
write entirely new commands, programs in the Lisp language to be run by
Emacs's own Lisp interpreter. Emacs is an "on-line extensible" system,
which means that it is divided into many functions that call each
other, any of which can be redefined in the middle of an editing
session. Almost any part of Emacs can be replaced without making a
separate copy of all of Emacs. Most of the editing commands of Emacs
are written in Lisp already; the few exceptions could have been written
in Lisp but are written in C for efficiency. Although only a programmer
can write an extension, anybody can use it afterward. If you want to
learn Emacs Lisp programming, we recommend the `Introduction to Emacs
Lisp' by Robert J. Chassell, also published by the Free Software
Foundation.
When run under the X Window System, Emacs provides its own menus and
convenient bindings to mouse buttons. But Emacs can provide many of the
benefits of a window system on a text-only terminal. For instance, you
can look at or edit several files at once, move text between files, and
edit files while running shell commands.
The Organization of the Screen
******************************
On a text-only terminal, the Emacs display occupies the whole screen.
On the X Window System, Emacs creates its own X windows to use. We use
the term "frame" to mean an entire text-only screen or an entire X
window used by Emacs. Emacs uses both kinds of frames in the same way
to display your editing. Emacs normally starts out with just one frame,
but you can create additional frames if you wish. *Note Frames::.
When you start Emacs, the entire frame except for the first and last
lines is devoted to the text you are editing. This area is called the
"window". The first line is a "menu bar", and the last line is a
special "echo area" or "minibuffer window" where prompts appear and
where you can enter responses. See below for more information about
these special lines.
You can subdivide the large text window horizontally or vertically
into multiple text windows, each of which can be used for a different
file (*note Windows::.). In this manual, the word "window" always
refers to the subdivisions of a frame within Emacs.
The window that the cursor is in is the "selected window", in which
editing takes place. Most Emacs commands implicitly apply to the text
in the selected window (though mouse commands generally operate on
whatever window you click them in, whether selected or not). The other
windows display text for reference only, unless/until you select them.
If you use multiple frames under the X Window System, then giving the
input focus to a particular frame selects a window in that frame.
Each window's last line is a "mode line", which describes what is
going on in that window. It appears in inverse video, if the terminal
supports that, and its contents begin with `--:-- *scratch*' when
Emacs starts. The mode line displays status information such as what
buffer is being displayed above it in the window, what major and minor
modes are in use, and whether the buffer contains unsaved changes.
Point
=====
Within Emacs, the terminal's cursor shows the location at which
editing commands will take effect. This location is called "point".
Many Emacs commands move point through the text, so that you can edit at
different places in it. You can also place point by clicking mouse
button 1.
While the cursor appears to point *at* a character, you should think
of point as *between* two characters; it points *before* the character
that appears under the cursor. For example, if your text looks like
`frob' with the cursor over the `b', then point is between the `o' and
the `b'. If you insert the character `!' at that position, the result
is `fro!b', with point between the `!' and the `b'. Thus, the cursor
remains over the `b', as before.
Sometimes people speak of "the cursor" when they mean "point," or
speak of commands that move point as "cursor motion" commands.
Terminals have only one cursor, and when output is in progress it
must appear where the typing is being done. This does not mean that
point is moving. It is only that Emacs has no way to show you the
location of point except when the terminal is idle.
If you are editing several files in Emacs, each in its own buffer,
each buffer has its own point location. A buffer that is not currently
displayed remembers where point is in case you display it again later.
When there are multiple windows in a frame, each window has its own
point location. The cursor shows the location of point in the selected
window. This also is how you can tell which window is selected. If the
same buffer appears in more than one window, each window has its own
position for point in that buffer.
When there are multiple frames, each frame can display one cursor.
The cursor in the selected frame is solid; the cursor in other frames is
a hollow box, and appears in the window that would be selected if you
give the input focus to that frame.
The term `point' comes from the character `.', which was the command
in TECO (the language in which the original Emacs was written) for
accessing the value now called `point'.
The Echo Area
=============
The line at the bottom of the frame (below the mode line) is the
"echo area". It is used to display small amounts of text for several
purposes.
"Echoing" means displaying the characters that you type. Outside
Emacs, the operating system normally echoes all your input. Emacs
handles echoing differently.
Single-character commands do not echo in Emacs, and multi-character
commands echo only if you pause while typing them. As soon as you pause
for more than a second in the middle of a command, Emacs echoes all the
characters of the command so far. This is to "prompt" you for the rest
of the command. Once echoing has started, the rest of the command
echoes immediately as you type it. This behavior is designed to give
confident users fast response, while giving hesitant users maximum
feedback. You can change this behavior by setting a variable (*note
Display Vars::.).
If a command cannot be executed, it may print an "error message" in
the echo area. Error messages are accompanied by a beep or by flashing
the screen. Also, any input you have typed ahead is thrown away when
an error happens.
Some commands print informative messages in the echo area. These
messages look much like error messages, but they are not announced with
a beep and do not throw away input. Sometimes the message tells you
what the command has done, when this is not obvious from looking at the
text being edited. Sometimes the sole purpose of a command is to print
a message giving you specific information--for example, `C-x =' prints
a message describing the character position of point in the text and
its current column in the window. Commands that take a long time often
display messages ending in `...' while they are working, and add `done'
at the end when they are finished.
Echo-area informative messages are saved in an editor buffer named
`*Messages*'. (We have not explained buffers yet; see *Note Buffers::,
for more information about them.) If you miss a message that appears
briefly on the screen, you can switch to the `*Messages*' buffer to see
it again. (Successive progress messages are often collapsed into one
in that buffer.)
The size of `*Messages*' is limited to a certain number of lines.
The variable `message-log-max' specifies how many lines. Once the
buffer has that many lines, each line added at the end deletes one line
from the beginning. *Note Variables::, for how to set variables such as
`message-log-max'.
The echo area is also used to display the "minibuffer", a window that
is used for reading arguments to commands, such as the name of a file
to be edited. When the minibuffer is in use, the echo area begins with
a prompt string that usually ends with a colon; also, the cursor
appears in that line because it is the selected window. You can always
get out of the minibuffer by typing `C-g'. *Note Minibuffer::.
The Mode Line
=============
Each text window's last line is a "mode line", which describes what
is going on in that window. When there is only one text window, the
mode line appears right above the echo area; it is the next-to-last line
on the frame. The mode line is in inverse video if the terminal
supports that, and it starts and ends with dashes.
Normally, the mode line looks like this:
-CS:CH BUF (MAJOR MINOR)--LINE--POS------
This gives information about the buffer being displayed in the window:
the buffer's name, what major and minor modes are in use, whether the
buffer's text has been changed, and how far down the buffer you are
currently looking.
CH contains two stars `**' if the text in the buffer has been edited
(the buffer is "modified"), or `--' if the buffer has not been edited.
For a read-only buffer, it is `%*' if the buffer is modified, and `%%'
otherwise.
BUF is the name of the window's "buffer". In most cases this is the
same as the name of a file you are editing. *Note Buffers::.
The buffer displayed in the selected window (the window that the
cursor is in) is also Emacs's selected buffer, the one that editing
takes place in. When we speak of what some command does to "the
buffer," we are talking about the currently selected buffer.
LINE is `L' followed by the current line number of point. This is
present when Line Number mode is enabled (which it normally is). You
can optionally display the current column number too, by turning on
Column Number mode (which is not enabled by default because it is
somewhat slower). *Note Optional Mode Line::.
POS tells you whether there is additional text above the top of the
window, or below the bottom. If your buffer is small and it is all
visible in the window, POS is `All'. Otherwise, it is `Top' if you are
looking at the beginning of the buffer, `Bot' if you are looking at the
end of the buffer, or `NN%', where NN is the percentage of the buffer
above the top of the window.
MAJOR is the name of the "major mode" in effect in the buffer. At
any time, each buffer is in one and only one of the possible major
modes. The major modes available include Fundamental mode (the least
specialized), Text mode, Lisp mode, C mode, Texinfo mode, and many
others. *Note Major Modes::, for details of how the modes differ and
how to select one.
Some major modes display additional information after the major mode
name. For example, Rmail buffers display the current message number and
the total number of messages. Compilation buffers and Shell buffers
display the status of the subprocess.
MINOR is a list of some of the "minor modes" that are turned on at
the moment in the window's chosen buffer. For example, `Fill' means
that Auto Fill mode is on. `Abbrev' means that Word Abbrev mode is on.
`Ovwrt' means that Overwrite mode is on. *Note Minor Modes::, for
more information. `Narrow' means that the buffer being displayed has
editing restricted to only a portion of its text. This is not really a
minor mode, but is like one. *Note Narrowing::. `Def' means that a
keyboard macro is being defined. *Note Keyboard Macros::.
In addition, if Emacs is currently inside a recursive editing level,
square brackets (`[...]') appear around the parentheses that surround
the modes. If Emacs is in one recursive editing level within another,
double square brackets appear, and so on. Since recursive editing
levels affect Emacs globally, not just one buffer, the square brackets
appear in every window's mode line or not in any of them. *Note
Recursive Edit::.
Non-windowing terminals can only show a single Emacs frame at a time
(*note Frames::.). On such terminals, the mode line displays the name
of the selected frame, after CH. The initial frame's name is `F1'.
CS states the coding system used for the file you are editing. A
dash indicates the default state of affairs: no code conversion, except
for end-of-line translation if the file contents call for that. `='
means no conversion whatsoever. Nontrivial code conversions are
represented by various letters--for example, `1' refers to ISO Latin-1.
*Note Coding Systems::, for more information. If you are using an
input method, a string of the form `I>' is added to the beginning of
CS; I identifies the input method. (Some input methods show `+' or `@'
instead of `>'.) *Note Input Methods::.
When you are using a character-only terminal (not a window system),
CS uses three characters to describe, respectively, the coding system
for keyboard input, the coding system for terminal output, and the
coding system used for the file you are editing.
When multibyte characters are not enabled, CS does not appear at
all. *Note Enabling Multibyte::.
The colon after CS can change to another string in certain
circumstances. Emacs uses newline to separate lines in the buffer.
Some files use different conventions for separating lines: either
carriage-return linefeed (the MS-DOS convention) or just carriage-return
(the Macintosh convention). If the buffer's file uses carriage-return
linefeed, the colon changes to either a backslash (`\') or `(DOS)',
depending on the operating system. If the file uses just
carriage-return, the colon indicator changes to either a forward slash
(`/') or `(Mac)'. On some systems, Emacs displays `(Unix)' instead of
the colon even for files that use newline to separate lines.
You can customize the mode line display for each of the end-of-line
formats by setting each of the variables `eol-mnemonic-unix',
`eol-mnemonic-dos', `eol-mnemonic-mac', and `eol-mnemonic-undecided' to
any string you find appropriate. *Note Variables::, for an explanation
how to set variables.
*Note Optional Mode Line::, for features that add other handy
information to the mode line, such as the current column number of
point, the current time, and whether new mail for you has arrived.
The Menu Bar
============
Each Emacs frame normally has a "menu bar" at the top which you can
use to perform certain common operations. There's no need to list them
here, as you can more easily see for yourself.
When you are using a window system, you can use the mouse to choose a
command from the menu bar. An arrow pointing right, after the menu
item, indicates that the item leads to a subsidiary menu; `...' at the
end means that the command will read arguments from the keyboard before
it actually does anything.
To view the full command name and documentation for a menu item, type
`C-h k', and then select the menu bar with the mouse in the usual way
(*note Key Help::.).
On text-only terminals with no mouse, you can use the menu bar by
typing `M-`' or <F10> (these run the command `tmm-menubar'). This
command enters a mode in which you can select a menu item from the
keyboard. A provisional choice appears in the echo area. You can use
the left and right arrow keys to move through the menu to different
choices. When you have found the choice you want, type <RET> to select
it.
Each menu item also has an assigned letter or digit which designates
that item; it is usually the initial of some word in the item's name.
This letter or digit is separated from the item name by `=>'. You can
type the item's letter or digit to select the item.
Some of the commands in the menu bar have ordinary key bindings as
well; if so, the menu lists one equivalent key binding in parentheses
after the item itself.
Kinds of User Input
===================
GNU Emacs uses an extension of the ASCII character set for keyboard
input; it also accepts non-character input events including function
keys and mouse button actions.
ASCII consists of 128 character codes. Some of these codes are
assigned graphic symbols such as `a' and `='; the rest are control
characters, such as `Control-a' (usually written `C-a' for short).
`C-a' gets its name from the fact that you type it by holding down the
<CTRL> key while pressing `a'.
Some ASCII control characters have special names, and most terminals
have special keys you can type them with: for example, <RET>, <TAB>,
<DEL> and <ESC>. The space character is usually referred to below as
<SPC>, even though strictly speaking it is a graphic character whose
graphic happens to be blank. Some keyboards have a key labeled
"linefeed" which is an alias for `C-j'.
Emacs extends the ASCII character set with thousands more printing
characters (*note International::.), additional control characters, and
a few more modifiers that can be combined with any character.
On ASCII terminals, there are only 32 possible control characters.
These are the control variants of letters and `@[]\^_'. In addition,
the shift key is meaningless with control characters: `C-a' and `C-A'
are the same character, and Emacs cannot distinguish them.
But the Emacs character set has room for control variants of all
printing characters, and for distinguishing between `C-a' and `C-A'. X
Windows makes it possible to enter all these characters. For example,
`C--' (that's Control-Minus) and `C-5' are meaningful Emacs commands
under X.
Another Emacs character-set extension is additional modifier bits.
Only one modifier bit is commonly used; it is called Meta. Every
character has a Meta variant; examples include `Meta-a' (normally
written `M-a', for short), `M-A' (not the same character as `M-a', but
those two characters normally have the same meaning in Emacs),
`M-<RET>', and `M-C-a'. For reasons of tradition, we usually write
`C-M-a' rather than `M-C-a'; logically speaking, the order in which the
modifier keys <CTRL> and <META> are mentioned does not matter.
Some terminals have a <META> key, and allow you to type Meta
characters by holding this key down. Thus, `Meta-a' is typed by
holding down <META> and pressing `a'. The <META> key works much like
the <SHIFT> key. Such a key is not always labeled <META>, however, as
this function is often a special option for a key with some other
primary purpose.
If there is no <META> key, you can still type Meta characters using
two-character sequences starting with <ESC>. Thus, to enter `M-a', you
could type `<ESC> a'. To enter `C-M-a', you would type `<ESC> C-a'.
<ESC> is allowed on terminals with <META> keys, too, in case you have
formed a habit of using it.
X Windows provides several other modifier keys that can be applied to
any input character. These are called <SUPER>, <HYPER> and <ALT>. We
write `s-', `H-' and `A-' to say that a character uses these modifiers.
Thus, `s-H-C-x' is short for `Super-Hyper-Control-x'. Not all X
terminals actually provide keys for these modifier flags--in fact, many
terminals have a key labeled <ALT> which is really a <META> key. The
standard key bindings of Emacs do not include any characters with these
modifiers. But you can assign them meanings of your own by customizing
Emacs.
Keyboard input includes keyboard keys that are not characters at all:
for example function keys and arrow keys. Mouse buttons are also
outside the gamut of characters. You can modify these events with the
modifier keys <CTRL>, <META>, <SUPER>, <HYPER> and <ALT>, just like
keyboard characters.
Input characters and non-character inputs are collectively called
"input events". *Note Input Events: (elisp)Input Events, for more
information. If you are not doing Lisp programming, but simply want to
redefine the meaning of some characters or non-character events, see
*Note Customization::.
ASCII terminals cannot really send anything to the computer except
ASCII characters. These terminals use a sequence of characters to
represent each function key. But that is invisible to the Emacs user,
because the keyboard input routines recognize these special sequences
and convert them to function key events before any other part of Emacs
gets to see them.
Keys
====
A "key sequence" ("key", for short) is a sequence of input events
that are meaningful as a unit--as "a single command." Some Emacs
command sequences are just one character or one event; for example,
just `C-f' is enough to move forward one character. But Emacs also has
commands that take two or more events to invoke.
If a sequence of events is enough to invoke a command, it is a
"complete key". Examples of complete keys include `C-a', `X', <RET>,
<NEXT> (a function key), <DOWN> (an arrow key), `C-x C-f', and `C-x 4
C-f'. If it isn't long enough to be complete, we call it a "prefix
key". The above examples show that `C-x' and `C-x 4' are prefix keys.
Every key sequence is either a complete key or a prefix key.
Most single characters constitute complete keys in the standard Emacs
command bindings. A few of them are prefix keys. A prefix key combines
with the following input event to make a longer key sequence, which may
itself be complete or a prefix. For example, `C-x' is a prefix key, so
`C-x' and the next input event combine to make a two-character key
sequence. Most of these key sequences are complete keys, including
`C-x C-f' and `C-x b'. A few, such as `C-x 4' and `C-x r', are
themselves prefix keys that lead to three-character key sequences.
There's no limit to the length of a key sequence, but in practice
people rarely use sequences longer than four events.
By contrast, you can't add more events onto a complete key. For
example, the two-character sequence `C-f C-k' is not a key, because the
`C-f' is a complete key in itself. It's impossible to give `C-f C-k'
an independent meaning as a command. `C-f C-k' is two key sequences,
not one.
All told, the prefix keys in Emacs are `C-c', `C-h', `C-x', `C-x
<RET>', `C-x @', `C-x a', `C-x n', `C-x r', `C-x v', `C-x 4', `C-x 5',
`C-x 6', <ESC>, `M-g' and `M-j'. But this list is not cast in
concrete; it is just a matter of Emacs's standard key bindings. If you
customize Emacs, you can make new prefix keys, or eliminate these.
*Note Key Bindings::.
If you do make or eliminate prefix keys, that changes the set of
possible key sequences. For example, if you redefine `C-f' as a
prefix, `C-f C-k' automatically becomes a key (complete, unless you
define it too as a prefix). Conversely, if you remove the prefix
definition of `C-x 4', then `C-x 4 f' (or `C-x 4 ANYTHING') is no
longer a key.
Typing the help character (`C-h' or <F1>) after a prefix character
displays a list of the commands starting with that prefix. There are a
few prefix characters for which `C-h' does not work--for historical
reasons, they have other meanings for `C-h' which are not easy to
change. But <F1> should work for all prefix characters.
Keys and Commands
=================
This manual is full of passages that tell you what particular keys
do. But Emacs does not assign meanings to keys directly. Instead,
Emacs assigns meanings to named "commands", and then gives keys their
meanings by "binding" them to commands.
Every command has a name chosen by a programmer. The name is usually
made of a few English words separated by dashes; for example,
`next-line' or `forward-word'. A command also has a "function
definition" which is a Lisp program; this is what makes the command do
what it does. In Emacs Lisp, a command is actually a special kind of
Lisp function; one which specifies how to read arguments for it and
call it interactively. For more information on commands and functions,
see *Note What Is a Function: (elisp)What Is a Function. (The
definition we use in this manual is simplified slightly.)
The bindings between keys and commands are recorded in various tables
called "keymaps". *Note Keymaps::.
When we say that "`C-n' moves down vertically one line" we are
glossing over a distinction that is irrelevant in ordinary use but is
vital in understanding how to customize Emacs. It is the command
`next-line' that is programmed to move down vertically. `C-n' has this
effect *because* it is bound to that command. If you rebind `C-n' to
the command `forward-word' then `C-n' will move forward by words
instead. Rebinding keys is a common method of customization.
In the rest of this manual, we usually ignore this subtlety to keep
things simple. To give the information needed for customization, we
state the name of the command which really does the work in parentheses
after mentioning the key that runs it. For example, we will say that
"The command `C-n' (`next-line') moves point vertically down," meaning
that `next-line' is a command that moves vertically down and `C-n' is a
key that is standardly bound to it.
While we are on the subject of information for customization only,
it's a good time to tell you about "variables". Often the description
of a command will say, "To change this, set the variable `mumble-foo'."
A variable is a name used to remember a value. Most of the variables
documented in this manual exist just to facilitate customization: some
command or other part of Emacs examines the variable and behaves
differently according to the value that you set. Until you are
interested in customizing, you can ignore the information about
variables. When you are ready to be interested, read the basic
information on variables, and then the information on individual
variables will make sense. *Note Variables::.
Character Set for Text
======================
Text in Emacs buffers is a sequence of 8-bit bytes. Each byte can
hold a single ASCII character. Both ASCII control characters (octal
codes 000 through 037, and 0177) and ASCII printing characters (codes
040 through 0176) are allowed; however, non-ASCII control characters
cannot appear in a buffer. The other modifier flags used in keyboard
input, such as Meta, are not allowed in buffers either.
Some ASCII control characters serve special purposes in text, and
have special names. For example, the newline character (octal code
012) is used in the buffer to end a line, and the tab character (octal
code 011) is used for indenting to the next tab stop column (normally
every 8 columns). *Note Text Display::.
Non-ASCII printing characters can also appear in buffers. When
multibyte characters are enabled, you can use any of the non-ASCII
printing characters that Emacs supports. They have character codes
starting at 256, octal 0400, and each one is represented as a sequence
of two or more bytes. *Note International::.
If you disable multibyte characters, then you can use only one
alphabet of non-ASCII characters, but they all fit in one byte. They
use codes 0200 through 0377. *Note Single-Byte European Support::.
Entering and Exiting Emacs
**************************
The usual way to invoke Emacs is with the shell command `emacs'.
Emacs clears the screen and then displays an initial help message and
copyright notice. Some operating systems discard all type-ahead when
Emacs starts up; they give Emacs no way to prevent this. Therefore, it
is advisable to wait until Emacs clears the screen before typing your
first editing command.
If you run Emacs from a shell window under the X Window System, run
it in the background with `emacs&'. This way, Emacs does not tie up
the shell window, so you can use that to run other shell commands while
Emacs operates its own X windows. You can begin typing Emacs commands
as soon as you direct your keyboard input to the Emacs frame.
When Emacs starts up, it makes a buffer named `*scratch*'. That's
the buffer you start out in. The `*scratch*' buffer uses Lisp
Interaction mode; you can use it to type Lisp expressions and evaluate
them, or you can ignore that capability and simply doodle. (You can
specify a different major mode for this buffer by setting the variable
`initial-major-mode' in your init file. *Note Init File::.)
It is possible to specify files to be visited, Lisp files to be
loaded, and functions to be called, by giving Emacs arguments in the
shell command line. *Note Command Arguments::. But we don't recommend
doing this. The feature exists mainly for compatibility with other
editors.
Many other editors are designed to be started afresh each time you
want to edit. You edit one file and then exit the editor. The next
time you want to edit either another file or the same one, you must run
the editor again. With these editors, it makes sense to use a
command-line argument to say which file to edit.
But starting a new Emacs each time you want to edit a different file
does not make sense. For one thing, this would be annoyingly slow. For
another, this would fail to take advantage of Emacs's ability to visit
more than one file in a single editing session. And it would lose the
other accumulated context, such as registers, undo history, and the mark
ring.
The recommended way to use GNU Emacs is to start it only once, just
after you log in, and do all your editing in the same Emacs session.
Each time you want to edit a different file, you visit it with the
existing Emacs, which eventually comes to have many files in it ready
for editing. Usually you do not kill the Emacs until you are about to
log out. *Note Files::, for more information on visiting more than one
file.
Exiting Emacs
=============
There are two commands for exiting Emacs because there are two kinds
of exiting: "suspending" Emacs and "killing" Emacs.
"Suspending" means stopping Emacs temporarily and returning control
to its parent process (usually a shell), allowing you to resume editing
later in the same Emacs job, with the same buffers, same kill ring,
same undo history, and so on. This is the usual way to exit.
"Killing" Emacs means destroying the Emacs job. You can run Emacs
again later, but you will get a fresh Emacs; there is no way to resume
the same editing session after it has been killed.
`C-z'
Suspend Emacs (`suspend-emacs') or iconify a frame
(`iconify-or-deiconify-frame').
`C-x C-c'
Kill Emacs (`save-buffers-kill-emacs').
To suspend Emacs, type `C-z' (`suspend-emacs'). This takes you back
to the shell from which you invoked Emacs. You can resume Emacs with
the shell command `%emacs' in most common shells.
On systems that do not support suspending programs, `C-z' starts an
inferior shell that communicates directly with the terminal. Emacs
waits until you exit the subshell. (The way to do that is probably
with `C-d' or `exit', but it depends on which shell you use.) The only
way on these systems to get back to the shell from which Emacs was run
(to log out, for example) is to kill Emacs.
Suspending also fails if you run Emacs under a shell that doesn't
support suspending programs, even if the system itself does support it.
In such a case, you can set the variable `cannot-suspend' to a
non-`nil' value to force `C-z' to start an inferior shell. (One might
also describe Emacs's parent shell as "inferior" for failing to support
job control properly, but that is a matter of taste.)
When Emacs communicates directly with an X server and creates its own
dedicated X windows, `C-z' has a different meaning. Suspending an
applications that uses its own X windows is not meaningful or useful.
Instead, `C-z' runs the command `iconify-or-deiconify-frame', which
temporarily closes up the selected Emacs frame (*note Frames::.). The
way to get back to a shell window is with the window manager.
To kill Emacs, type `C-x C-c' (`save-buffers-kill-emacs'). A
two-character key is used for this to make it harder to type. This
command first offers to save any modified file-visiting buffers. If you
do not save them all, it asks for reconfirmation with `yes' before
killing Emacs, since any changes not saved will be lost forever. Also,
if any subprocesses are still running, `C-x C-c' asks for confirmation
about them, since killing Emacs will kill the subprocesses immediately.
There is no way to restart an Emacs session once you have killed it.
You can, however, arrange for Emacs to record certain session
information, such as which files are visited, when you kill it, so that
the next time you restart Emacs it will try to visit the same files and
so on. *Note Saving Emacs Sessions::.
The operating system usually listens for certain special characters
whose meaning is to kill or suspend the program you are running. This
operating system feature is turned off while you are in Emacs. The
meanings of `C-z' and `C-x C-c' as keys in Emacs were inspired by the
use of `C-z' and `C-c' on several operating systems as the characters
for stopping or killing a program, but that is their only relationship
with the operating system. You can customize these keys to run any
commands of your choice (*note Keymaps::.).
Basic Editing Commands
**********************
We now give the basics of how to enter text, make corrections, and
save the text in a file. If this material is new to you, you might
learn it more easily by running the Emacs learn-by-doing tutorial. To
use the tutorial, run Emacs and type `Control-h t'
(`help-with-tutorial').
To clear the screen and redisplay, type `C-l' (`recenter').
Inserting Text
==============
To insert printing characters into the text you are editing, just
type them. This inserts the characters you type into the buffer at the
cursor (that is, at "point"; *note Point::.). The cursor moves
forward, and any text after the cursor moves forward too. If the text
in the buffer is `FOOBAR', with the cursor before the `B', then if you
type `XX', you get `FOOXXBAR', with the cursor still before the `B'.
To "delete" text you have just inserted, use <DEL>. <DEL> deletes
the character *before* the cursor (not the one that the cursor is on
top of or under; that is the character AFTER the cursor). The cursor
and all characters after it move backwards. Therefore, if you type a
printing character and then type <DEL>, they cancel out.
To end a line and start typing a new one, type <RET>. This inserts
a newline character in the buffer. If point is in the middle of a
line, <RET> splits the line. Typing <DEL> when the cursor is at the
beginning of a line deletes the preceding newline, thus joining the
line with the preceding line.
Emacs can split lines automatically when they become too long, if you
turn on a special minor mode called "Auto Fill" mode. *Note Filling::,
for how to use Auto Fill mode.
If you prefer to have text characters replace (overwrite) existing
text rather than shove it to the right, you can enable Overwrite mode,
a minor mode. *Note Minor Modes::.
Direct insertion works for printing characters and <SPC>, but other
characters act as editing commands and do not insert themselves. If you
need to insert a control character or a character whose code is above
200 octal, you must "quote" it by typing the character `Control-q'
(`quoted-insert') first. (This character's name is normally written
`C-q' for short.) There are two ways to use `C-q':
* `C-q' followed by any non-graphic character (even `C-g') inserts
that character.
* `C-q' followed by a sequence of octal digits inserts the character
with the specified octal character code. You can use any number of
octal digits; any non-digit terminates the sequence. If the
terminating character is <RET>, it serves only to terminate the
sequence; any other non-digit is itself used as input after
terminating the sequence. (The use of octal sequences is disabled
in ordinary non-binary Overwrite mode, to give you a convenient
way to insert a digit instead of overwriting with it.)
When multibyte characters are enabled, octal codes 0200 through 0377 are
not valid as characters; if you specify a code in this range, `C-q'
assumes that you intend to use some ISO Latin-N character set, and
converts the specified code to the corresponding Emacs character code.
*Note Enabling Multibyte::. You select *which* ISO Latin character set
though your choice of language environment (*note Language
Environments::.).
To use decimal or hexadecimal instead of octal, set the variable
`read-quoted-char-radix' to 10 or 16. If the radix is greater than 10,
some letters starting with `a' serve as part of a character code, just
like digits.
A numeric argument to `C-q' specifies how many copies of the quoted
character should be inserted (*note Arguments::.).
Customization information: <DEL> in most modes runs the command
`delete-backward-char'; <RET> runs the command `newline', and
self-inserting printing characters run the command `self-insert', which
inserts whatever character was typed to invoke it. Some major modes
rebind <DEL> to other commands.
Changing the Location of Point
==============================
To do more than insert characters, you have to know how to move point
(*note Point::.). The simplest way to do this is with arrow keys, or by
clicking the left mouse button where you want to move to.
There are also control and meta characters for cursor motion. Some
are equivalent to the arrow keys (these date back to the days before
terminals had arrow keys, and are usable on terminals which don't have
them). Others do more sophisticated things.
`C-a'
Move to the beginning of the line (`beginning-of-line').
`C-e'
Move to the end of the line (`end-of-line').
`C-f'
Move forward one character (`forward-char').
`C-b'
Move backward one character (`backward-char').
`M-f'
Move forward one word (`forward-word').
`M-b'
Move backward one word (`backward-word').
`C-n'
Move down one line, vertically (`next-line'). This command
attempts to keep the horizontal position unchanged, so if you
start in the middle of one line, you end in the middle of the
next. When on the last line of text, `C-n' creates a new line and
moves onto it.
`C-p'
Move up one line, vertically (`previous-line').
`M-r'
Move point to left margin, vertically centered in the window
(`move-to-window-line'). Text does not move on the screen.
A numeric argument says which screen line to place point on. It
counts screen lines down from the top of the window (zero for the
top line). A negative argument counts lines from the bottom (-1
for the bottom line).
`M-<'
Move to the top of the buffer (`beginning-of-buffer'). With
numeric argument N, move to N/10 of the way from the top. *Note
Arguments::, for more information on numeric arguments.
`M->'
Move to the end of the buffer (`end-of-buffer').
`M-x goto-char'
Read a number N and move point to buffer position N. Position 1
is the beginning of the buffer.
`M-x goto-line'
Read a number N and move point to line number N. Line 1 is the
beginning of the buffer.
`C-x C-n'
Use the current column of point as the "semipermanent goal column"
for `C-n' and `C-p' (`set-goal-column'). Henceforth, those
commands always move to this column in each line moved into, or as
close as possible given the contents of the line. This goal
column remains in effect until canceled.
`C-u C-x C-n'
Cancel the goal column. Henceforth, `C-n' and `C-p' once again
try to stick to a fixed horizontal position, as usual.
If you set the variable `track-eol' to a non-`nil' value, then `C-n'
and `C-p' when at the end of the starting line move to the end of
another line. Normally, `track-eol' is `nil'. *Note Variables::, for
how to set variables such as `track-eol'.
Normally, `C-n' on the last line of a buffer appends a newline to
it. If the variable `next-line-add-newlines' is `nil', then `C-n' gets
an error instead (like `C-p' on the first line).
Erasing Text
============
`<DEL>'
Delete the character before point (`delete-backward-char').
`C-d'
Delete the character after point (`delete-char').
`C-k'
Kill to the end of the line (`kill-line').
`M-d'
Kill forward to the end of the next word (`kill-word').
`M-<DEL>'
Kill back to the beginning of the previous word
(`backward-kill-word').
You already know about the <DEL> key which deletes the character
before point (that is, before the cursor). Another key, `Control-d'
(`C-d' for short), deletes the character after point (that is, the
character that the cursor is on). This shifts the rest of the text on
the line to the left. If you type `C-d' at the end of a line, it joins
together that line and the next line.
To erase a larger amount of text, use the `C-k' key, which kills a
line at a time. If you type `C-k' at the beginning or middle of a
line, it kills all the text up to the end of the line. If you type
`C-k' at the end of a line, it joins that line and the next line.
*Note Killing::, for more flexible ways of killing text.
Undoing Changes
===============
You can undo all the recent changes in the buffer text, up to a
certain point. Each buffer records changes individually, and the undo
command always applies to the current buffer. Usually each editing
command makes a separate entry in the undo records, but some commands
such as `query-replace' make many entries, and very simple commands
such as self-inserting characters are often grouped to make undoing less
tedious.
`C-x u'
Undo one batch of changes--usually, one command worth (`undo').
`C-_'
The same.
`C-u C-x u'
Undo one batch of changes in the region.
The command `C-x u' or `C-_' is how you undo. The first time you
give this command, it undoes the last change. Point moves back to
where it was before the command that made the change.
Consecutive repetitions of `C-_' or `C-x u' undo earlier and earlier
changes, back to the limit of the undo information available. If all
recorded changes have already been undone, the undo command prints an
error message and does nothing.
Any command other than an undo command breaks the sequence of undo
commands. Starting from that moment, the previous undo commands become
ordinary changes that you can undo. Thus, to redo changes you have
undone, type `C-f' or any other command that will harmlessly break the
sequence of undoing, then type more undo commands.
Ordinary undo applies to all changes made in the current buffer. You
can also perform "selective undo", limited to the current region. To
do this, specify the region you want, then run the `undo' command with
a prefix argument (the value does not matter): `C-u C-x u' or `C-u
C-_'. This undoes the most recent change in the region. To undo
further changes in the same region, repeat the `undo' command (no
prefix argument is needed). In Transient Mark mode, any use of `undo'
when there is an active region performs selective undo; you do not need
a prefix argument.
If you notice that a buffer has been modified accidentally, the
easiest way to recover is to type `C-_' repeatedly until the stars
disappear from the front of the mode line. At this time, all the
modifications you made have been canceled. Whenever an undo command
makes the stars disappear from the mode line, it means that the buffer
contents are the same as they were when the file was last read in or
saved.
If you do not remember whether you changed the buffer deliberately,
type `C-_' once. When you see the last change you made undone, you
will see whether it was an intentional change. If it was an accident,
leave it undone. If it was deliberate, redo the change as described
above.
Not all buffers record undo information. Buffers whose names start
with spaces don't; these buffers are used internally by Emacs and its
extensions to hold text that users don't normally look at or edit.
You cannot undo mere cursor motion; only changes in the buffer
contents save undo information. However, some cursor motion commands
set the mark, so if you use these commands from time to time, you can
move back to the neighborhoods you have moved through by popping the
mark ring (*note Mark Ring::.).
When the undo information for a buffer becomes too large, Emacs
discards the oldest undo information from time to time (during garbage
collection). You can specify how much undo information to keep by
setting two variables: `undo-limit' and `undo-strong-limit'. Their
values are expressed in units of bytes of space.
The variable `undo-limit' sets a soft limit: Emacs keeps undo data
for enough commands to reach this size, and perhaps exceed it, but does
not keep data for any earlier commands beyond that. Its default value
is 20000. The variable `undo-strong-limit' sets a stricter limit: the
command which pushes the size past this amount is itself forgotten.
Its default value is 30000.
Regardless of the values of those variables, the most recent change
is never discarded, so there is no danger that garbage collection
occurring right after an unintentional large change might prevent you
from undoing it.
The reason the `undo' command has two keys, `C-x u' and `C-_', set
up to run it is that it is worthy of a single-character key, but on
some keyboards it is not obvious how to type `C-_'. `C-x u' is an
alternative you can type straightforwardly on any terminal.
Files
=====
The commands described above are sufficient for creating and altering
text in an Emacs buffer; the more advanced Emacs commands just make
things easier. But to keep any text permanently you must put it in a
"file". Files are named units of text which are stored by the
operating system for you to retrieve later by name. To look at or use
the contents of a file in any way, including editing the file with
Emacs, you must specify the file name.
Consider a file named `/usr/rms/foo.c'. In Emacs, to begin editing
this file, type
C-x C-f /usr/rms/foo.c <RET>
Here the file name is given as an "argument" to the command `C-x C-f'
(`find-file'). That command uses the "minibuffer" to read the
argument, and you type <RET> to terminate the argument (*note
Minibuffer::.).
Emacs obeys the command by "visiting" the file: creating a buffer,
copying the contents of the file into the buffer, and then displaying
the buffer for you to edit. If you alter the text, you can "save" the
new text in the file by typing `C-x C-s' (`save-buffer'). This makes
the changes permanent by copying the altered buffer contents back into
the file `/usr/rms/foo.c'. Until you save, the changes exist only
inside Emacs, and the file `foo.c' is unaltered.
To create a file, just visit the file with `C-x C-f' as if it
already existed. This creates an empty buffer in which you can insert
the text you want to put in the file. The file is actually created when
you save this buffer with `C-x C-s'.
Of course, there is a lot more to learn about using files. *Note
Files::.
Help
====
If you forget what a key does, you can find out with the Help
character, which is `C-h' (or <F1>, which is an alias for `C-h'). Type
`C-h k' followed by the key you want to know about; for example, `C-h k
C-n' tells you all about what `C-n' does. `C-h' is a prefix key; `C-h
k' is just one of its subcommands (the command `describe-key'). The
other subcommands of `C-h' provide different kinds of help. Type `C-h'
twice to get a description of all the help facilities. *Note Help::.
Blank Lines
===========
Here are special commands and techniques for putting in and taking
out blank lines.
`C-o'
Insert one or more blank lines after the cursor (`open-line').
`C-x C-o'
Delete all but one of many consecutive blank lines
(`delete-blank-lines').
When you want to insert a new line of text before an existing line,
you can do it by typing the new line of text, followed by <RET>.
However, it may be easier to see what you are doing if you first make a
blank line and then insert the desired text into it. This is easy to do
using the key `C-o' (`open-line'), which inserts a newline after point
but leaves point in front of the newline. After `C-o', type the text
for the new line. `C-o F O O' has the same effect as `F O O <RET>',
except for the final location of point.
You can make several blank lines by typing `C-o' several times, or
by giving it a numeric argument to tell it how many blank lines to make.
*Note Arguments::, for how. If you have a fill prefix, then `C-o'
command inserts the fill prefix on the new line, when you use it at the
beginning of a line. *Note Fill Prefix::.
The easy way to get rid of extra blank lines is with the command
`C-x C-o' (`delete-blank-lines'). `C-x C-o' in a run of several blank
lines deletes all but one of them. `C-x C-o' on a solitary blank line
deletes that blank line. When point is on a nonblank line, `C-x C-o'
deletes any blank lines following that nonblank line.
Continuation Lines
==================
If you add too many characters to one line without breaking it with
<RET>, the line will grow to occupy two (or more) lines on the screen,
with a `\' at the extreme right margin of all but the last of them.
The `\' says that the following screen line is not really a distinct
line in the text, but just the "continuation" of a line too long to fit
the screen. Continuation is also called "line wrapping".
Sometimes it is nice to have Emacs insert newlines automatically when
a line gets too long. Continuation on the screen does not do that. Use
Auto Fill mode (*note Filling::.) if that's what you want.
As an alternative to continuation, Emacs can display long lines by
"truncation". This means that all the characters that do not fit in
the width of the screen or window do not appear at all. They remain in
the buffer, temporarily invisible. `$' is used in the last column
instead of `\' to inform you that truncation is in effect.
Truncation instead of continuation happens whenever horizontal
scrolling is in use, and optionally in all side-by-side windows (*note
Windows::.). You can enable truncation for a particular buffer by
setting the variable `truncate-lines' to non-`nil' in that buffer.
(*Note Variables::.) Altering the value of `truncate-lines' makes it
local to the current buffer; until that time, the default value is in
effect. The default is initially `nil'. *Note Locals::.
*Note Display Vars::, for additional variables that affect how text
is displayed.
Cursor Position Information
===========================
Here are commands to get information about the size and position of
parts of the buffer, and to count lines.
`M-x what-page'
Print page number of point, and line number within page.
`M-x what-line'
Print line number of point in the buffer.
`M-x line-number-mode'
Toggle automatic display of current line number.
`M-='
Print number of lines in the current region (`count-lines-region').
*Note Mark::, for information about the region.
`C-x ='
Print character code of character after point, character position
of point, and column of point (`what-cursor-position').
There are two commands for working with line numbers. `M-x
what-line' computes the current line number and displays it in the echo
area. To go to a given line by number, use `M-x goto-line'; it prompts
you for the number. These line numbers count from one at the beginning
of the buffer.
You can also see the current line number in the mode line; *Note
Mode Line::. If you narrow the buffer, then the line number in the
mode line is relative to the accessible portion (*note Narrowing::.).
By contrast, `what-line' shows both the line number relative to the
narrowed region and the line number relative to the whole buffer.
By contrast, `M-x what-page' counts pages from the beginning of the
file, and counts lines within the page, printing both numbers. *Note
Pages::.
While on this subject, we might as well mention `M-='
(`count-lines-region'), which prints the number of lines in the region
(*note Mark::.). *Note Pages::, for the command `C-x l' which counts
the lines in the current page.
The command `C-x =' (`what-cursor-position') can be used to find out
the column that the cursor is in, and other miscellaneous information
about point. It prints a line in the echo area that looks like this:
Char: c (0143, 99, 0x63) point=21044 of 26883(78%) column 53
(In fact, this is the output produced when point is before the `column'
in the example.)
The four values after `Char:' describe the character that follows
point, first by showing it and then by giving its character code in
octal, decimal and hex. For a non-ASCII multibyte character, these are
followed by `ext' and the character's representation, in hex, in the
buffer's coding system, if that coding system encodes the character
safely and with a single byte (*note Coding Systems::.). If the
character's encoding is longer than one byte, Emacs shows `ext ...'.
`point=' is followed by the position of point expressed as a
character count. The front of the buffer counts as position 1, one
character later as 2, and so on. The next, larger, number is the total
number of characters in the buffer. Afterward in parentheses comes the
position expressed as a percentage of the total size.
`column' is followed by the horizontal position of point, in columns
from the left edge of the window.
If the buffer has been narrowed, making some of the text at the
beginning and the end temporarily inaccessible, `C-x =' prints
additional text describing the currently accessible range. For
example, it might display this:
Char: C (0103, 67, 0x43) point=252 of 889(28%) <231 - 599> column 0
where the two extra numbers give the smallest and largest character
position that point is allowed to assume. The characters between those
two positions are the accessible ones. *Note Narrowing::.
If point is at the end of the buffer (or the end of the accessible
part), the `C-x =' output does not describe a character after point.
The output might look like this:
point=26957 of 26956(100%) column 0
`C-u C-x =' displays additional information about a character, in
place of the buffer coordinates and column: the character set name and
the codes that identify the character within that character set; ASCII
characters are identified as belonging to the `ASCII' character set.
In addition, the full character encoding, even if it takes more than a
single byte, is shown after `ext'. Here's an example for a Latin-1
character A with a grave accent in a buffer whose coding system is
iso-2022-7bit(1):
Char: `A (04300, 2240, 0x8c0, ext ESC , A @) (latin-iso8859-1 64)
---------- Footnotes ----------
(1) On terminals that support Latin-1 characters, the character
shown after `Char:' is displayed as the actual glyph of A with grave
accent.
Numeric Arguments
=================
In mathematics and computer usage, the word "argument" means "data
provided to a function or operation." You can give any Emacs command a
"numeric argument" (also called a "prefix argument"). Some commands
interpret the argument as a repetition count. For example, `C-f' with
an argument of ten moves forward ten characters instead of one. With
these commands, no argument is equivalent to an argument of one.
Negative arguments tell most such commands to move or act in the
opposite direction.
If your terminal keyboard has a <META> key, the easiest way to
specify a numeric argument is to type digits and/or a minus sign while
holding down the <META> key. For example,
M-5 C-n
would move down five lines. The characters `Meta-1', `Meta-2', and so
on, as well as `Meta--', do this because they are keys bound to
commands (`digit-argument' and `negative-argument') that are defined to
contribute to an argument for the next command. Digits and `-'
modified with Control, or Control and Meta, also specify numeric
arguments.
Another way of specifying an argument is to use the `C-u'
(`universal-argument') command followed by the digits of the argument.
With `C-u', you can type the argument digits without holding down
modifier keys; `C-u' works on all terminals. To type a negative
argument, type a minus sign after `C-u'. Just a minus sign without
digits normally means -1.
`C-u' followed by a character which is neither a digit nor a minus
sign has the special meaning of "multiply by four." It multiplies the
argument for the next command by four. `C-u' twice multiplies it by
sixteen. Thus, `C-u C-u C-f' moves forward sixteen characters. This
is a good way to move forward "fast," since it moves about 1/5 of a line
in the usual size screen. Other useful combinations are `C-u C-n',
`C-u C-u C-n' (move down a good fraction of a screen), `C-u C-u C-o'
(make "a lot" of blank lines), and `C-u C-k' (kill four lines).
Some commands care only about whether there is an argument, and not
about its value. For example, the command `M-q' (`fill-paragraph') with
no argument fills text; with an argument, it justifies the text as well.
(*Note Filling::, for more information on `M-q'.) Plain `C-u' is a
handy way of providing an argument for such commands.
Some commands use the value of the argument as a repeat count, but do
something peculiar when there is no argument. For example, the command
`C-k' (`kill-line') with argument N kills N lines, including their
terminating newlines. But `C-k' with no argument is special: it kills
the text up to the next newline, or, if point is right at the end of
the line, it kills the newline itself. Thus, two `C-k' commands with
no arguments can kill a nonblank line, just like `C-k' with an argument
of one. (*Note Killing::, for more information on `C-k'.)
A few commands treat a plain `C-u' differently from an ordinary
argument. A few others may treat an argument of just a minus sign
differently from an argument of -1. These unusual cases are described
when they come up; they are always for reasons of convenience of use of
the individual command.
You can use a numeric argument to insert multiple copies of a
character. This is straightforward unless the character is a digit; for
example, `C-u 6 4 a' inserts 64 copies of the character `a'. But this
does not work for inserting digits; `C-u 6 4 1' specifies an argument
of 641, rather than inserting anything. To separate the digit to
insert from the argument, type another `C-u'; for example, `C-u 6 4 C-u
1' does insert 64 copies of the character `1'.
We use the term "prefix argument" as well as "numeric argument" to
emphasize that you type the argument before the command, and to
distinguish these arguments from minibuffer arguments that come after
the command.
Repeating a Command
===================
The command `C-x z' (`repeat') provides another way to repeat an
Emacs command many times. This command repeats the previous Emacs
command, whatever that was. Repeating a command uses the same arguments
that were used before; it does not read new arguments each time.
To repeat the command more than once, type additional `z''s: each
`z' repeats the command one more time. Repetition ends when you type a
character other than `z', or press a mouse button.
For example, suppose you type `C-u 2 0 C-d' to delete 20 characters.
You can repeat that command (including its argument) three additional
times, to delete a total of 80 characters, by typing `C-x z z z'. The
first `C-x z' repeats the command once, and each subsequent `z' repeats
it once again.
The Minibuffer
**************
The "minibuffer" is the facility used by Emacs commands to read
arguments more complicated than a single number. Minibuffer arguments
can be file names, buffer names, Lisp function names, Emacs command
names, Lisp expressions, and many other things, depending on the command
reading the argument. You can use the usual Emacs editing commands in
the minibuffer to edit the argument text.
When the minibuffer is in use, it appears in the echo area, and the
terminal's cursor moves there. The beginning of the minibuffer line
displays a "prompt" which says what kind of input you should supply and
how it will be used. Often this prompt is derived from the name of the
command that the argument is for. The prompt normally ends with a
colon.
Sometimes a "default argument" appears in parentheses after the
colon; it too is part of the prompt. The default will be used as the
argument value if you enter an empty argument (for example, just type
<RET>). For example, commands that read buffer names always show a
default, which is the name of the buffer that will be used if you type
just <RET>.
The simplest way to enter a minibuffer argument is to type the text
you want, terminated by <RET> which exits the minibuffer. You can
cancel the command that wants the argument, and get out of the
minibuffer, by typing `C-g'.
Since the minibuffer uses the screen space of the echo area, it can
conflict with other ways Emacs customarily uses the echo area. Here is
how Emacs handles such conflicts:
* If a command gets an error while you are in the minibuffer, this
does not cancel the minibuffer. However, the echo area is needed
for the error message and therefore the minibuffer itself is
hidden for a while. It comes back after a few seconds, or as soon
as you type anything.
* If in the minibuffer you use a command whose purpose is to print a
message in the echo area, such as `C-x =', the message is printed
normally, and the minibuffer is hidden for a while. It comes back
after a few seconds, or as soon as you type anything.
* Echoing of keystrokes does not take place while the minibuffer is
in use.
Minibuffers for File Names
==========================
Sometimes the minibuffer starts out with text in it. For example,
when you are supposed to give a file name, the minibuffer starts out
containing the "default directory", which ends with a slash. This is
to inform you which directory the file will be found in if you do not
specify a directory.
For example, the minibuffer might start out with these contents:
Find File: /u2/emacs/src/
where `Find File: ' is the prompt. Typing `buffer.c' specifies the
file `/u2/emacs/src/buffer.c'. To find files in nearby directories,
use `..'; thus, if you type `../lisp/simple.el', you will get the file
named `/u2/emacs/lisp/simple.el'. Alternatively, you can kill with
`M-<DEL>' the directory names you don't want (*note Words::.).
If you don't want any of the default, you can kill it with `C-a
C-k'. But you don't need to kill the default; you can simply ignore it.
Insert an absolute file name, one starting with a slash or a tilde,
after the default directory. For example, to specify the file
`/etc/termcap', just insert that name, giving these minibuffer contents:
Find File: /u2/emacs/src//etc/termcap
GNU Emacs gives a special meaning to a double slash (which is not
normally a useful thing to write): it means, "ignore everything before
the second slash in the pair." Thus, `/u2/emacs/src/' is ignored in
the example above, and you get the file `/etc/termcap'.
If you set `insert-default-directory' to `nil', the default
directory is not inserted in the minibuffer. This way, the minibuffer
starts out empty. But the name you type, if relative, is still
interpreted with respect to the same default directory.
Editing in the Minibuffer
=========================
The minibuffer is an Emacs buffer (albeit a peculiar one), and the
usual Emacs commands are available for editing the text of an argument
you are entering.
Since <RET> in the minibuffer is defined to exit the minibuffer, you
can't use it to insert a newline in the minibuffer. To do that, type
`C-o' or `C-q C-j'. (Recall that a newline is really the character
control-J.)
The minibuffer has its own window which always has space on the
screen but acts as if it were not there when the minibuffer is not in
use. When the minibuffer is in use, its window is just like the
others; you can switch to another window with `C-x o', edit text in
other windows and perhaps even visit more files, before returning to
the minibuffer to submit the argument. You can kill text in another
window, return to the minibuffer window, and then yank the text to use
it in the argument. *Note Windows::.
There are some restrictions on the use of the minibuffer window,
however. You cannot switch buffers in it--the minibuffer and its
window are permanently attached. Also, you cannot split or kill the
minibuffer window. But you can make it taller in the normal fashion
with `C-x ^'. If you enable Resize-Minibuffer mode, then the
minibuffer window expands vertically as necessary to hold the text that
you put in the minibuffer. Use `M-x resize-minibuffer-mode' to enable
or disable this minor mode (*note Minor Modes::.).
Scrolling works specially in the minibuffer window. When the
minibuffer is just one line high, and it contains a long line of text
that won't fit on the screen, scrolling automatically maintains an
overlap of a certain number of characters from one continuation line to
the next. The variable `minibuffer-scroll-overlap' specifies how many
characters of overlap; the default is 20.
If while in the minibuffer you issue a command that displays help
text of any sort in another window, you can use the `C-M-v' command
while in the minibuffer to scroll the help text. This lasts until you
exit the minibuffer. This feature is especially useful if a completing
minibuffer gives you a list of possible completions. *Note Other
Window::.
Emacs normally disallows most commands that use the minibuffer while
the minibuffer is active. This rule is to prevent recursive minibuffers
from confusing novice users. If you want to be able to use such
commands in the minibuffer, set the variable
`enable-recursive-minibuffers' to a non-`nil' value.
Completion
==========
For certain kinds of arguments, you can use "completion" to enter
the argument value. Completion means that you type part of the
argument, then Emacs visibly fills in the rest, or as much as can be
determined from the part you have typed.
When completion is available, certain keys--<TAB>, <RET>, and
<SPC>--are rebound to complete the text present in the minibuffer into
a longer string that it stands for, by matching it against a set of
"completion alternatives" provided by the command reading the argument.
`?' is defined to display a list of possible completions of what you
have inserted.
For example, when `M-x' uses the minibuffer to read the name of a
command, it provides a list of all available Emacs command names to
complete against. The completion keys match the text in the minibuffer
against all the command names, find any additional name characters
implied by the ones already present in the minibuffer, and add those
characters to the ones you have given. This is what makes it possible
to type `M-x ins <SPC> b <RET>' instead of `M-x insert-buffer <RET>'
(for example).
Case is normally significant in completion, because it is significant
in most of the names that you can complete (buffer names, file names and
command names). Thus, `fo' does not complete to `Foo'. Completion
does ignore case distinctions for certain arguments in which case does
not matter.
Completion Example
------------------
A concrete example may help here. If you type `M-x au <TAB>', the
<TAB> looks for alternatives (in this case, command names) that start
with `au'. There are several, including `auto-fill-mode' and
`auto-save-mode'--but they are all the same as far as `auto-', so the
`au' in the minibuffer changes to `auto-'.
If you type <TAB> again immediately, there are multiple
possibilities for the very next character--it could be any of
`cfilrs'--so no more characters are added; instead, <TAB> displays a
list of all possible completions in another window.
If you go on to type `f <TAB>', this <TAB> sees `auto-f'. The only
command name starting this way is `auto-fill-mode', so completion fills
in the rest of that. You now have `auto-fill-mode' in the minibuffer
after typing just `au <TAB> f <TAB>'. Note that <TAB> has this effect
because in the minibuffer it is bound to the command
`minibuffer-complete' when completion is available.
Completion Commands
-------------------
Here is a list of the completion commands defined in the minibuffer
when completion is available.
`<TAB>'
Complete the text in the minibuffer as much as possible
(`minibuffer-complete').
`<SPC>'
Complete the minibuffer text, but don't go beyond one word
(`minibuffer-complete-word').
`<RET>'
Submit the text in the minibuffer as the argument, possibly
completing first as described below
(`minibuffer-complete-and-exit').
`?'
Print a list of all possible completions of the text in the
minibuffer (`minibuffer-list-completions').
<SPC> completes much like <TAB>, but never goes beyond the next
hyphen or space. If you have `auto-f' in the minibuffer and type
<SPC>, it finds that the completion is `auto-fill-mode', but it stops
completing after `fill-'. This gives `auto-fill-'. Another <SPC> at
this point completes all the way to `auto-fill-mode'. <SPC> in the
minibuffer when completion is available runs the command
`minibuffer-complete-word'.
Here are some commands you can use to choose a completion from a
window that displays a list of completions:
`Mouse-2'
Clicking mouse button 2 on a completion in the list of possible
completions chooses that completion (`mouse-choose-completion').
You normally use this command while point is in the minibuffer;
but you must click in the list of completions, not in the
minibuffer itself.
`<PRIOR>'
`M-v'
Typing <PRIOR> or <PAGE-UP>, or `M-v', while in the minibuffer,
selects the window showing the completion list buffer
(`switch-to-completions'). This paves the way for using the
commands below. (Selecting that window in the usual ways has the
same effect, but this way is more convenient.)
`<RET>'
Typing <RET> *in the completion list buffer* chooses the
completion that point is in or next to (`choose-completion'). To
use this command, you must first switch windows to the window that
shows the list of completions.
`<RIGHT>'
Typing the right-arrow key <RIGHT> *in the completion list buffer*
moves point to the following completion (`next-completion').
`<LEFT>'
Typing the left-arrow key <LEFT> *in the completion list buffer*
moves point toward the beginning of the buffer, to the previous
completion (`previous-completion').
Strict Completion
-----------------
There are three different ways that <RET> can work in completing
minibuffers, depending on how the argument will be used.
* "Strict" completion is used when it is meaningless to give any
argument except one of the known alternatives. For example, when
`C-x k' reads the name of a buffer to kill, it is meaningless to
give anything but the name of an existing buffer. In strict
completion, <RET> refuses to exit if the text in the minibuffer
does not complete to an exact match.
* "Cautious" completion is similar to strict completion, except that
<RET> exits only if the text was an exact match already, not
needing completion. If the text is not an exact match, <RET> does
not exit, but it does complete the text. If it completes to an
exact match, a second <RET> will exit.
Cautious completion is used for reading file names for files that
must already exist.
* "Permissive" completion is used when any string whatever is
meaningful, and the list of completion alternatives is just a
guide. For example, when `C-x C-f' reads the name of a file to
visit, any file name is allowed, in case you want to create a
file. In permissive completion, <RET> takes the text in the
minibuffer exactly as given, without completing it.
The completion commands display a list of all possible completions in
a window whenever there is more than one possibility for the very next
character. Also, typing `?' explicitly requests such a list. If the
list of completions is long, you can scroll it with `C-M-v' (*note
Other Window::.).
Completion Options
------------------
When completion is done on file names, certain file names are usually
ignored. The variable `completion-ignored-extensions' contains a list
of strings; a file whose name ends in any of those strings is ignored
as a possible completion. The standard value of this variable has
several elements including `".o"', `".elc"', `".dvi"' and `"~"'. The
effect is that, for example, `foo' can complete to `foo.c' even though
`foo.o' exists as well. However, if *all* the possible completions end
in "ignored" strings, then they are not ignored. Ignored extensions do
not apply to lists of completions--those always mention all possible
completions.
Normally, a completion command that finds the next character is
undetermined automatically displays a list of all possible completions.
If the variable `completion-auto-help' is set to `nil', this does not
happen, and you must type `?' to display the possible completions.
The `complete' library implements a more powerful kind of completion
that can complete multiple words at a time. For example, it can
complete the command name abbreviation `p-b' into `print-buffer',
because no other command starts with two words whose initials are `p'
and `b'. To use this library, put `(load "complete")' in your
`~/.emacs' file (*note Init File::.).
Icomplete mode presents a constantly-updated display that tells you
what completions are available for the text you've entered so far. The
command to enable or disable this minor mode is `M-x icomplete-mode'.
Minibuffer History
==================
Every argument that you enter with the minibuffer is saved on a
"minibuffer history list" so that you can use it again later in another
argument. Special commands load the text of an earlier argument in the
minibuffer. They discard the old minibuffer contents, so you can think
of them as moving through the history of previous arguments.
`<UP>'
`M-p'
Move to the next earlier argument string saved in the minibuffer
history (`previous-history-element').
`<DOWN>'
`M-n'
Move to the next later argument string saved in the minibuffer
history (`next-history-element').
`M-r REGEXP <RET>'
Move to an earlier saved argument in the minibuffer history that
has a match for REGEXP (`previous-matching-history-element').
`M-s REGEXP <RET>'
Move to a later saved argument in the minibuffer history that has a
match for REGEXP (`next-matching-history-element').
The simplest way to reuse the saved arguments in the history list is
to move through the history list one element at a time. While in the
minibuffer, use `M-p' or up-arrow (`previous-history-element') to "move
to" the next earlier minibuffer input, and use `M-n' or down-arrow
(`next-history-element') to "move to" the next later input.
The previous input that you fetch from the history entirely replaces
the contents of the minibuffer. To use it as the argument, exit the
minibuffer as usual with <RET>. You can also edit the text before you
reuse it; this does not change the history element that you "moved" to,
but your new argument does go at the end of the history list in its own
right.
For many minibuffer arguments there is a "default" value. In some
cases, the minibuffer history commands know the default value. Then you
can insert the default value into the minibuffer as text by using `M-n'
to move "into the future" in the history. Eventually we hope to make
this feature available whenever the minibuffer has a default value.
There are also commands to search forward or backward through the
history; they search for history elements that match a regular
expression that you specify with the minibuffer. `M-r'
(`previous-matching-history-element') searches older elements in the
history, while `M-s' (`next-matching-history-element') searches newer
elements. By special dispensation, these commands can use the
minibuffer to read their arguments even though you are already in the
minibuffer when you issue them. As with incremental searching, an
uppercase letter in the regular expression makes the search
case-sensitive (*note Search Case::.).
All uses of the minibuffer record your input on a history list, but
there are separate history lists for different kinds of arguments. For
example, there is a list for file names, used by all the commands that
read file names. (As a special feature, this history list records the
absolute file name, no more and no less, even if that is not how you
entered the file name.)
There are several other very specific history lists, including one
for command names read by `M-x', one for buffer names, one for arguments
of commands like `query-replace', and one for compilation commands read
by `compile'. Finally, there is one "miscellaneous" history list that
most minibuffer arguments use.
The variable `history-length' specifies the maximum length of a
minibuffer history list; once a list gets that long, the oldest element
is deleted each time an element is added. If the value of
`history-length' is `t', though, there is no maximum length and
elements are never deleted.
Repeating Minibuffer Commands
=============================
Every command that uses the minibuffer at least once is recorded on a
special history list, together with the values of its arguments, so that
you can repeat the entire command. In particular, every use of `M-x'
is recorded there, since `M-x' uses the minibuffer to read the command
name.
`C-x <ESC> <ESC>'
Re-execute a recent minibuffer command (`repeat-complex-command').
`M-x list-command-history'
Display the entire command history, showing all the commands `C-x
<ESC> <ESC>' can repeat, most recent first.
`C-x <ESC> <ESC>' is used to re-execute a recent minibuffer-using
command. With no argument, it repeats the last such command. A
numeric argument specifies which command to repeat; one means the last
one, and larger numbers specify earlier ones.
`C-x <ESC> <ESC>' works by turning the previous command into a Lisp
expression and then entering a minibuffer initialized with the text for
that expression. If you type just <RET>, the command is repeated as
before. You can also change the command by editing the Lisp
expression. Whatever expression you finally submit is what will be
executed. The repeated command is added to the front of the command
history unless it is identical to the most recently executed command
already there.
Even if you don't understand Lisp syntax, it will probably be obvious
which command is displayed for repetition. If you do not change the
text, it will repeat exactly as before.
Once inside the minibuffer for `C-x <ESC> <ESC>', you can use the
minibuffer history commands (`M-p', `M-n', `M-r', `M-s'; *note
Minibuffer History::.) to move through the history list of saved entire
commands. After finding the desired previous command, you can edit its
expression as usual and then resubmit it by typing <RET> as usual.
The list of previous minibuffer-using commands is stored as a Lisp
list in the variable `command-history'. Each element is a Lisp
expression which describes one command and its arguments. Lisp programs
can re-execute a command by calling `eval' with the `command-history'
element.
Running Commands by Name
************************
The Emacs commands that are used often or that must be quick to type
are bound to keys--short sequences of characters--for convenient use.
Other Emacs commands that do not need to be brief are not bound to
keys; to run them, you must refer to them by name.
A command name is, by convention, made up of one or more words,
separated by hyphens; for example, `auto-fill-mode' or `manual-entry'.
The use of English words makes the command name easier to remember than
a key made up of obscure characters, even though it is more characters
to type.
The way to run a command by name is to start with `M-x', type the
command name, and finish it with <RET>. `M-x' uses the minibuffer to
read the command name. <RET> exits the minibuffer and runs the
command. The string `M-x' appears at the beginning of the minibuffer
as a "prompt" to remind you to enter the name of a command to be run.
*Note Minibuffer::, for full information on the features of the
minibuffer.
You can use completion to enter the command name. For example, the
command `forward-char' can be invoked by name by typing
M-x forward-char <RET>
or
M-x forw <TAB> c <RET>
Note that `forward-char' is the same command that you invoke with the
key `C-f'. You can run any Emacs command by name using `M-x', whether
or not any keys are bound to it.
If you type `C-g' while the command name is being read, you cancel
the `M-x' command and get out of the minibuffer, ending up at top level.
To pass a numeric argument to the command you are invoking with
`M-x', specify the numeric argument before the `M-x'. `M-x' passes the
argument along to the command it runs. The argument value appears in
the prompt while the command name is being read.
If the command you type has a key binding of its own, Emacs mentions
this in the echo area, two seconds after the command finishes (if you
don't type anything else first). For example, if you type `M-x
forward-word', the message says that you can run the same command more
easily by typing `M-f'. You can turn off these messages by setting
`suggest-key-bindings' to `nil'.
Normally, when describing in this manual a command that is run by
name, we omit the <RET> that is needed to terminate the name. Thus we
might speak of `M-x auto-fill-mode' rather than `M-x auto-fill-mode
<RET>'. We mention the <RET> only when there is a need to emphasize
its presence, such as when we show the command together with following
arguments.
`M-x' works by running the command `execute-extended-command', which
is responsible for reading the name of another command and invoking it.
Help
****
Emacs provides extensive help features accessible through a single
character, `C-h'. `C-h' is a prefix key that is used only for
documentation-printing commands. The characters that you can type after
`C-h' are called "help options". One help option is `C-h'; that is how
you ask for help about using `C-h'. To cancel, type `C-g'. The
function key <F1> is equivalent to `C-h'.
`C-h C-h' (`help-for-help') displays a list of the possible help
options, each with a brief description. Before you type a help option,
you can use <SPC> or <DEL> to scroll through the list.
`C-h' or <F1> means "help" in various other contexts as well. For
example, in the middle of `query-replace', it describes the options
available for how to operate on the current match. After a prefix key,
it displays a list of the alternatives that can follow the prefix key.
(A few prefix keys don't support `C-h', because they define other
meanings for it, but they all support <F1>.)
Most help buffers use a special major mode, Help mode, which lets you
scroll conveniently with <SPC> and <DEL>.
Help Summary
============
Here is a summary of the defined help commands.
`C-h a REGEXP <RET>'
Display a list of commands whose names match REGEXP
(`apropos-command').
`C-h b'
Display a table of all key bindings in effect now, in this order:
minor mode bindings, major mode bindings, and global bindings
(`describe-bindings').
`C-h c KEY'
Print the name of the command that KEY runs
(`describe-key-briefly'). Here `c' stands for `character'. For
more extensive information on KEY, use `C-h k'.
`C-h f FUNCTION <RET>'
Display documentation on the Lisp function named FUNCTION
(`describe-function'). Since commands are Lisp functions, a
command name may be used.
`C-h h'
Display the `hello' file, which shows examples of various character
sets.
`C-h i'
Run Info, the program for browsing documentation files (`info').
The complete Emacs manual is available on-line in Info.
`C-h k KEY'
Display the name and documentation of the command that KEY runs
(`describe-key').
`C-h l'
Display a description of the last 100 characters you typed
(`view-lossage').
`C-h m'
Display documentation of the current major mode (`describe-mode').
`C-h n'
Display documentation of Emacs changes, most recent first
(`view-emacs-news').
`C-h p'
Find packages by topic keyword (`finder-by-keyword').
`C-h s'
Display current contents of the syntax table, plus an explanation
of what they mean (`describe-syntax'). *Note Syntax::.
`C-h t'
Enter the Emacs interactive tutorial (`help-with-tutorial').
`C-h v VAR <RET>'
Display the documentation of the Lisp variable VAR
(`describe-variable').
`C-h w COMMAND <RET>'
Print which keys run the command named COMMAND (`where-is').
`C-h C CODING <RET>'
Describe coding system CODING (`describe-coding-system').
`C-h C <RET>'
Describe the coding systems currently in use.
`C-h I METHOD <RET>'
Describe an input method (`describe-input-method').
`C-h L LANGUAGE-ENV <RET>'
Describe information on the character sets, coding systems and
input methods used for language environment LANGUAGE-ENV
(`describe-language-environment').
`C-h C-c'
Display the copying conditions for GNU Emacs.
`C-h C-d'
Display information about getting new versions of GNU Emacs.
`C-h C-f FUNCTION <RET>'
Enter Info and go to the node documenting the Emacs function
FUNCTION (`Info-goto-emacs-command-node').
`C-h C-k KEY'
Enter Info and go to the node where the key sequence KEY is
documented (`Info-goto-emacs-key-command-node').
`C-h C-p'
Display information about the GNU Project.
`C-h <TAB> SYMBOL <RET>'
Display the Info documentation on symbol SYMBOL according to the
programming language you are editing (`info-lookup-symbol').
Documentation for a Key
=======================
The most basic `C-h' options are `C-h c' (`describe-key-briefly')
and `C-h k' (`describe-key'). `C-h c KEY' prints in the echo area the
name of the command that KEY is bound to. For example, `C-h c C-f'
prints `forward-char'. Since command names are chosen to describe what
the commands do, this is a good way to get a very brief description of
what KEY does.
`C-h k KEY' is similar but gives more information: it displays the
documentation string of the command as well as its name. This is too
big for the echo area, so a window is used for the display.
`C-h c' and `C-h k' work for any sort of key sequences, including
function keys and mouse events.
Help by Command or Variable Name
================================
`C-h f' (`describe-function') reads the name of a Lisp function
using the minibuffer, then displays that function's documentation string
in a window. Since commands are Lisp functions, you can use this to get
the documentation of a command that you know by name. For example,
C-h f auto-fill-mode <RET>
displays the documentation of `auto-fill-mode'. This is the only way
to get the documentation of a command that is not bound to any key (one
which you would normally run using `M-x').
`C-h f' is also useful for Lisp functions that you are planning to
use in a Lisp program. For example, if you have just written the
expression `(make-vector len)' and want to check that you are using
`make-vector' properly, type `C-h f make-vector <RET>'. Because `C-h
f' allows all function names, not just command names, you may find that
some of your favorite abbreviations that work in `M-x' don't work in
`C-h f'. An abbreviation may be unique among command names yet fail to
be unique when other function names are allowed.
The function name for `C-h f' to describe has a default which is
used if you type <RET> leaving the minibuffer empty. The default is
the function called by the innermost Lisp expression in the buffer
around point, *provided* that is a valid, defined Lisp function name.
For example, if point is located following the text `(make-vector (car
x)', the innermost list containing point is the one that starts with
`(make-vector', so the default is to describe the function
`make-vector'.
`C-h f' is often useful just to verify that you have the right
spelling for the function name. If `C-h f' mentions a name from the
buffer as the default, that name must be defined as a Lisp function. If
that is all you want to know, just type `C-g' to cancel the `C-h f'
command, then go on editing.
`C-h w COMMAND <RET>' tells you what keys are bound to COMMAND. It
prints a list of the keys in the echo area. If it says the command is
not on any key, you must use `M-x' to run it. `C-h w' runs the command
`where-is'.
`C-h v' (`describe-variable') is like `C-h f' but describes Lisp
variables instead of Lisp functions. Its default is the Lisp symbol
around or before point, but only if that is the name of a known Lisp
variable. *Note Variables::.
Apropos
=======
A more sophisticated sort of question to ask is, "What are the
commands for working with files?" To ask this question, type `C-h a
file <RET>', which displays a list of all command names that contain
`file', including `copy-file', `find-file', and so on. With each
command name appears a brief description of how to use the command, and
what keys you can currently invoke it with. For example, it would say
that you can invoke `find-file' by typing `C-x C-f'. The `a' in `C-h
a' stands for `Apropos'; `C-h a' runs the command `apropos-command'.
This command normally checks only commands (interactive functions); if
you specify a prefix argument, it checks noninteractive functions as
well.
Because `C-h a' looks only for functions whose names contain the
string you specify, you must use ingenuity in choosing the string. If
you are looking for commands for killing backwards and `C-h a
kill-backwards <RET>' doesn't reveal any, don't give up. Try just
`kill', or just `backwards', or just `back'. Be persistent. Also note
that you can use a regular expression as the argument, for more
flexibility (*note Regexps::.).
Here is a set of arguments to give to `C-h a' that covers many
classes of Emacs commands, since there are strong conventions for naming
the standard Emacs commands. By giving you a feel for the naming
conventions, this set should also serve to aid you in developing a
technique for picking `apropos' strings.
char, line, word, sentence, paragraph, region, page, sexp, list,
defun, rect, buffer, frame, window, face, file, dir, register,
mode, beginning, end, forward, backward, next, previous, up, down,
search, goto, kill, delete, mark, insert, yank, fill, indent,
case, change, set, what, list, find, view, describe, default.
To list all user variables that match a regexp, use the command `M-x
apropos-variable'. This command shows only user variables and
customization options by default; if you specify a prefix argument, it
checks all variables.
To list all Lisp symbols that contain a match for a regexp, not just
the ones that are defined as commands, use the command `M-x apropos'
instead of `C-h a'. This command does not check key bindings by
default; specify a numeric argument if you want it to check them.
The `apropos-documentation' command is like `apropos' except that it
searches documentation strings as well as symbol names for matches for
the specified regular expression.
The `apropos-value' command is like `apropos' except that it
searches symbols' values for matches for the specified regular
expression. This command does not check function definitions or
property lists by default; specify a numeric argument if you want it to
check them.
If the variable `apropos-do-all' is non-`nil', the commands above
all behave as if they had been given a prefix argument.
If you want more information about a function definition, variable or
symbol property listed in the Apropos buffer, you can click on it with
`Mouse-2' or move there and type <RET>.
Keyword Search for Lisp Libraries
=================================
The `C-h p' command lets you search the standard Emacs Lisp
libraries by topic keywords. Here is a partial list of keywords you can
use:
abbrev --- abbreviation handling, typing shortcuts, macros.
bib --- support for the bibliography processor `bib'.
c --- C and C++ language support.
calendar --- calendar and time management support.
comm --- communications, networking, remote access to files.
data --- support for editing files of data.
docs --- support for Emacs documentation.
emulations --- emulations of other editors.
extensions --- Emacs Lisp language extensions.
faces --- support for using faces (fonts and colors; *note Faces::.).
frames --- support for Emacs frames and window systems.
games --- games, jokes and amusements.
hardware --- support for interfacing with exotic hardware.
help --- support for on-line help systems.
hypermedia --- support for links within text, or other media types.
i18n --- internationalization and alternate character-set support.
internal --- code for Emacs internals, build process, defaults.
languages --- specialized modes for editing programming languages.
lisp --- support for using Lisp (including Emacs Lisp).
local --- libraries local to your site.
maint --- maintenance aids for the Emacs development group.
mail --- modes for electronic-mail handling.
matching --- searching and matching.
news --- support for netnews reading and posting.
non-text --- support for editing files that are not ordinary text.
oop --- support for object-oriented programming.
outlines --- hierarchical outlining.
processes --- process, subshell, compilation, and job control support.
terminals --- support for terminal types.
tex --- support for the TeX formatter.
tools --- programming tools.
unix --- front-ends/assistants for, or emulators of, Unix features.
vms --- support code for VMS.
wp --- word processing.
Help for International Language Support
=======================================
You can use the command `C-h L' (`describe-language-environment') to
find out the support for a specific language environment. *Note
Language Environments::. This tells you which languages this language
environment is useful for, and lists the character sets, coding
systems, and input methods that go with it. It also shows some sample
text to illustrate scripts.
The command `C-h h' (`view-hello-file') displays the file
`etc/HELLO', which shows how to say "hello" in many languages.
The command `C-h I' (`describe-input-method') describes information
about input methods--either a specified input method, or by default the
input method in use. *Note Input Methods::.
The command `C-h C' (`describe-coding-system') describes information
about coding systems--either a specified coding system, or the ones
currently in use. *Note Coding Systems::.
Help Mode Commands
==================
Help buffers provide the commands of View mode (*note Misc File
Ops::.), plus a few special commands of their own.
`<SPC>'
Scroll forward.
`<DEL>'
Scroll backward.
`<RET>'
Follow a cross reference at point.
`<TAB>'
Move point forward to the next cross reference.
`S-<TAB>'
Move point back to the previous cross reference.
`Mouse-2'
Follow a cross reference that you click on.
When a command name (*note Running Commands by Name: M-x.) or
variable name (*note Variables::.) appears in the documentation, it
normally appears inside paired single-quotes. You can click on the name
with `Mouse-2', or move point there and type <RET>, to view the
documentation of that command or variable. Use `C-c C-b' to retrace
your steps.
There are convenient commands for moving point to cross references in
the help text. <TAB> (`help-next-ref') moves point down to the next
cross reference. Use `S-<TAB>' to move point up to the previous cross
reference (`help-previous-ref').
Other Help Commands
===================
`C-h i' (`info') runs the Info program, which is used for browsing
through structured documentation files. The entire Emacs manual is
available within Info. Eventually all the documentation of the GNU
system will be available. Type `h' after entering Info to run a
tutorial on using Info.
If you specify a numeric argument, `C-h i' prompts for the name of a
documentation file. This way, you can browse a file which doesn't have
an entry in the top-level Info menu. It is also handy when you need to
get to the documentation quickly, and you know the exact name of the
file.
There are two special help commands for accessing Emacs documentation
through Info. `C-h C-f FUNCTION <RET>' enters Info and goes straight
to the documentation of the Emacs function FUNCTION. `C-h C-k KEY'
enters Info and goes straight to the documentation of the key KEY.
These two keys run the commands `Info-goto-emacs-command-node' and
`Info-goto-emacs-key-command-node'.
When editing a program, if you have an Info version of the manual for
the programming language, you can use the command `C-h C-i' to refer to
the manual documentation for a symbol (keyword, function or variable).
The details of how this command works depend on the major mode.
If something surprising happens, and you are not sure what commands
you typed, use `C-h l' (`view-lossage'). `C-h l' prints the last 100
command characters you typed in. If you see commands that you don't
know, you can use `C-h c' to find out what they do.
Emacs has numerous major modes, each of which redefines a few keys
and makes a few other changes in how editing works. `C-h m'
(`describe-mode') prints documentation on the current major mode, which
normally describes all the commands that are changed in this mode.
`C-h b' (`describe-bindings') and `C-h s' (`describe-syntax')
present other information about the current Emacs mode. `C-h b'
displays a list of all the key bindings now in effect; the local
bindings defined by the current minor modes first, then the local
bindings defined by the current major mode, and finally the global
bindings (*note Key Bindings::.). `C-h s' displays the contents of the
syntax table, with explanations of each character's syntax (*note
Syntax::.).
You can get a similar list for a particular prefix key by typing
`C-h' after the prefix key. (There are a few prefix keys for which
this does not work--those that provide their own bindings for `C-h'.
One of these is <ESC>, because `<ESC> C-h' is actually `C-M-h', which
marks a defun.)
The other `C-h' options display various files of useful information.
`C-h C-w' displays the full details on the complete absence of
warranty for GNU Emacs. `C-h n' (`view-emacs-news') displays the file
`emacs/etc/NEWS', which contains documentation on Emacs changes
arranged chronologically. `C-h F' (`view-emacs-FAQ') displays the
Emacs frequently-answered-questions list. `C-h t'
(`help-with-tutorial') displays the learn-by-doing Emacs tutorial.
`C-h C-c' (`describe-copying') displays the file `emacs/etc/COPYING',
which tells you the conditions you must obey in distributing copies of
Emacs. `C-h C-d' (`describe-distribution') displays the file
`emacs/etc/DISTRIB', which tells you how you can order a copy of the
latest version of Emacs. `C-h C-p' (`describe-project') displays
general information about the GNU Project.
The Mark and the Region
***********************
Many Emacs commands operate on an arbitrary contiguous part of the
current buffer. To specify the text for such a command to operate on,
you set "the mark" at one end of it, and move point to the other end.
The text between point and the mark is called "the region". Emacs
highlights the region whenever there is one, if you enable Transient
Mark mode (*note Transient Mark::.).
You can move point or the mark to adjust the boundaries of the
region. It doesn't matter which one is set first chronologically, or
which one comes earlier in the text. Once the mark has been set, it
remains where you put it until you set it again at another place. Each
Emacs buffer has its own mark, so that when you return to a buffer that
had been selected previously, it has the same mark it had before.
Many commands that insert text, such as `C-y' (`yank') and `M-x
insert-buffer', position point and the mark at opposite ends of the
inserted text, so that the region contains the text just inserted.
Aside from delimiting the region, the mark is also useful for
remembering a spot that you may want to go back to. To make this
feature more useful, each buffer remembers 16 previous locations of the
mark in the "mark ring".
Setting the Mark
================
Here are some commands for setting the mark:
`C-<SPC>'
Set the mark where point is (`set-mark-command').
`C-@'
The same.
`C-x C-x'
Interchange mark and point (`exchange-point-and-mark').
`Drag-Mouse-1'
Set point and the mark around the text you drag across.
`Mouse-3'
Set the mark where point is, then move point to where you click
(`mouse-save-then-kill').
For example, suppose you wish to convert part of the buffer to upper
case, using the `C-x C-u' (`upcase-region') command, which operates on
the text in the region. You can first go to the beginning of the text
to be capitalized, type `C-<SPC>' to put the mark there, move to the
end, and then type `C-x C-u'. Or, you can set the mark at the end of
the text, move to the beginning, and then type `C-x C-u'.
The most common way to set the mark is with the `C-<SPC>' command
(`set-mark-command'). This sets the mark where point is. Then you can
move point away, leaving the mark behind.
There are two ways to set the mark with the mouse. You can drag
mouse button one across a range of text; that puts point where you
release the mouse button, and sets the mark at the other end of that
range. Or you can click mouse button three, which sets the mark at
point (like `C-<SPC>') and then moves point (like `Mouse-1'). Both of
these methods copy the region into the kill ring in addition to setting
the mark; that gives behavior consistent with other window-driven
applications, but if you don't want to modify the kill ring, you must
use keyboard commands to set the mark. *Note Mouse Commands::.
Ordinary terminals have only one cursor, so there is no way for Emacs
to show you where the mark is located. You have to remember. The usual
solution to this problem is to set the mark and then use it soon, before
you forget where it is. Alternatively, you can see where the mark is
with the command `C-x C-x' (`exchange-point-and-mark') which puts the
mark where point was and point where the mark was. The extent of the
region is unchanged, but the cursor and point are now at the previous
position of the mark. In Transient Mark mode, this command reactivates
the mark.
`C-x C-x' is also useful when you are satisfied with the position of
point but want to move the other end of the region (where the mark is);
do `C-x C-x' to put point at that end of the region, and then move it.
A second use of `C-x C-x', if necessary, puts the mark at the new
position with point back at its original position.
There is no such character as `C-<SPC>' in ASCII; when you type
<SPC> while holding down <CTRL>, what you get on most ordinary
terminals is the character `C-@'. This key is actually bound to
`set-mark-command'. But unless you are unlucky enough to have a
terminal where typing `C-<SPC>' does not produce `C-@', you might as
well think of this character as `C-<SPC>'. Under X, `C-<SPC>' is
actually a distinct character, but its binding is still
`set-mark-command'.
Transient Mark Mode
===================
Emacs can highlight the current region, using X Windows. But
normally it does not. Why not?
Highlighting the region doesn't work well ordinarily in Emacs,
because once you have set a mark, there is *always* a region (in that
buffer). And highlighting the region all the time would be a nuisance.
You can turn on region highlighting by enabling Transient Mark mode.
This is a more rigid mode of operation in which the region "lasts" only
temporarily, so you must set up a region for each command that uses
one. In Transient Mark mode, most of the time there is no region;
therefore, highlighting the region when it exists is convenient.
To enable Transient Mark mode, type `M-x transient-mark-mode'. This
command toggles the mode, so you can repeat the command to turn off the
mode.
Here are the details of Transient Mark mode:
* To set the mark, type `C-<SPC>' (`set-mark-command'). This makes
the mark active; as you move point, you will see the region
highlighting grow and shrink.
* The mouse commands for specifying the mark also make it active.
So do keyboard commands whose purpose is to specify a region,
including `M-@', `C-M-@', `M-h', `C-M-h', `C-x C-p', and `C-x h'.
* When the mark is active, you can execute commands that operate on
the region, such as killing, indenting, or writing to a file.
* Any change to the buffer, such as inserting or deleting a
character, deactivates the mark. This means any subsequent
command that operates on a region will get an error and refuse to
operate. You can make the region active again by typing `C-x C-x'.
* Commands like `M->' and `C-s' that "leave the mark behind" in
addition to some other primary purpose do not activate the new
mark. You can activate the new region by executing `C-x C-x'
(`exchange-point-and-mark').
* `C-s' when the mark is active does not alter the mark.
* Quitting with `C-g' deactivates the mark.
Highlighting of the region uses the `region' face; you can customize
how the region is highlighted by changing this face. *Note Face
Customization::.
When multiple windows show the same buffer, they can have different
regions, because they can have different values of point (though they
all share one common mark position). Ordinarily, only the selected
window highlights its region (*note Windows::.). However, if the
variable `highlight-nonselected-windows' is non-`nil', then each window
highlights its own region (provided that Transient Mark mode is enabled
and the window's buffer's mark is active).
When Transient Mark mode is not enabled, every command that sets the
mark also activates it, and nothing ever deactivates it.
If the variable `mark-even-if-inactive' is non-`nil' in Transient
Mark mode, then commands can use the mark and the region even when it
is inactive. Region highlighting appears and disappears just as it
normally does in Transient Mark mode, but the mark doesn't really go
away when the highlighting disappears.
Transient Mark mode is also sometimes known as "Zmacs mode" because
the Zmacs editor on the MIT Lisp Machine handled the mark in a similar
way.
Operating on the Region
=======================
Once you have a region and the mark is active, here are some of the
ways you can operate on the region:
* Kill it with `C-w' (*note Killing::.).
* Save it in a register with `C-x r s' (*note Registers::.).
* Save it in a buffer or a file (*note Accumulating Text::.).
* Convert case with `C-x C-l' or `C-x C-u' (*note Case::.).
* Indent it with `C-x <TAB>' or `C-M-\' (*note Indentation::.).
* Fill it as text with `M-x fill-region' (*note Filling::.).
* Print hardcopy with `M-x print-region' (*note Hardcopy::.).
* Evaluate it as Lisp code with `M-x eval-region' (*note Lisp
Eval::.).
Most commands that operate on the text in the region have the word
`region' in their names.
Commands to Mark Textual Objects
================================
Here are the commands for placing point and the mark around a textual
object such as a word, list, paragraph or page.
`M-@'
Set mark after end of next word (`mark-word'). This command and
the following one do not move point.
`C-M-@'
Set mark after end of next Lisp expression (`mark-sexp').
`M-h'
Put region around current paragraph (`mark-paragraph').
`C-M-h'
Put region around current Lisp defun (`mark-defun').
`C-x h'
Put region around entire buffer (`mark-whole-buffer').
`C-x C-p'
Put region around current page (`mark-page').
`M-@' (`mark-word') puts the mark at the end of the next word, while
`C-M-@' (`mark-sexp') puts it at the end of the next Lisp expression.
These commands handle arguments just like `M-f' and `C-M-f'.
Other commands set both point and mark, to delimit an object in the
buffer. For example, `M-h' (`mark-paragraph') moves point to the
beginning of the paragraph that surrounds or follows point, and puts
the mark at the end of that paragraph (*note Paragraphs::.). It
prepares the region so you can indent, case-convert, or kill a whole
paragraph.
`C-M-h' (`mark-defun') similarly puts point before and the mark
after the current or following defun (*note Defuns::.). `C-x C-p'
(`mark-page') puts point before the current page, and mark at the end
(*note Pages::.). The mark goes after the terminating page delimiter
(to include it), while point goes after the preceding page delimiter
(to exclude it). A numeric argument specifies a later page (if
positive) or an earlier page (if negative) instead of the current page.
Finally, `C-x h' (`mark-whole-buffer') sets up the entire buffer as
the region, by putting point at the beginning and the mark at the end.
In Transient Mark mode, all of these commands activate the mark.
The Mark Ring
=============
Aside from delimiting the region, the mark is also useful for
remembering a spot that you may want to go back to. To make this
feature more useful, each buffer remembers 16 previous locations of the
mark, in the "mark ring". Commands that set the mark also push the old
mark onto this ring. To return to a marked location, use `C-u C-<SPC>'
(or `C-u C-@'); this is the command `set-mark-command' given a numeric
argument. It moves point to where the mark was, and restores the mark
from the ring of former marks. Thus, repeated use of this command
moves point to all of the old marks on the ring, one by one. The mark
positions you move through in this way are not lost; they go to the end
of the ring.
Each buffer has its own mark ring. All editing commands use the
current buffer's mark ring. In particular, `C-u C-<SPC>' always stays
in the same buffer.
Many commands that can move long distances, such as `M-<'
(`beginning-of-buffer'), start by setting the mark and saving the old
mark on the mark ring. This is to make it easier for you to move back
later. Searches set the mark if they move point. You can tell when a
command sets the mark because it displays `Mark Set' in the echo area.
If you want to move back to the same place over and over, the mark
ring may not be convenient enough. If so, you can record the position
in a register for later retrieval (*note RegPos::.).
The variable `mark-ring-max' specifies the maximum number of entries
to keep in the mark ring. If that many entries exist and another one
is pushed, the last one in the list is discarded. Repeating `C-u
C-<SPC>' cycles through the positions currently in the ring.
The variable `mark-ring' holds the mark ring itself, as a list of
marker objects, with the most recent first. This variable is local in
every buffer.
The Global Mark Ring
====================
In addition to the ordinary mark ring that belongs to each buffer,
Emacs has a single "global mark ring". It records a sequence of
buffers in which you have recently set the mark, so you can go back to
those buffers.
Setting the mark always makes an entry on the current buffer's mark
ring. If you have switched buffers since the previous mark setting, the
new mark position makes an entry on the global mark ring also. The
result is that the global mark ring records a sequence of buffers that
you have been in, and, for each buffer, a place where you set the mark.
The command `C-x C-<SPC>' (`pop-global-mark') jumps to the buffer
and position of the latest entry in the global ring. It also rotates
the ring, so that successive uses of `C-x C-<SPC>' take you to earlier
and earlier buffers.
Deletion and Killing
====================
Most commands which erase text from the buffer save it in the kill
ring so that you can move or copy it to other parts of the buffer.
These commands are known as "kill" commands. The rest of the commands
that erase text do not save it in the kill ring; they are known as
"delete" commands. (This distinction is made only for erasure of text
in the buffer.) If you do a kill or delete command by mistake, you can
use the `C-x u' (`undo') command to undo it (*note Undo::.).
The delete commands include `C-d' (`delete-char') and <DEL>
(`delete-backward-char'), which delete only one character at a time,
and those commands that delete only spaces or newlines. Commands that
can destroy significant amounts of nontrivial data generally kill. The
commands' names and individual descriptions use the words `kill' and
`delete' to say which they do.
Deletion
--------
`C-d'
Delete next character (`delete-char').
`<DEL>'
Delete previous character (`delete-backward-char').
`M-\'
Delete spaces and tabs around point (`delete-horizontal-space').
`M-<SPC>'
Delete spaces and tabs around point, leaving one space
(`just-one-space').
`C-x C-o'
Delete blank lines around the current line (`delete-blank-lines').
`M-^'
Join two lines by deleting the intervening newline, along with any
indentation following it (`delete-indentation').
The most basic delete commands are `C-d' (`delete-char') and <DEL>
(`delete-backward-char'). `C-d' deletes the character after point, the
one the cursor is "on top of." This doesn't move point. <DEL> deletes
the character before the cursor, and moves point back. You can delete
newlines like any other characters in the buffer; deleting a newline
joins two lines. Actually, `C-d' and <DEL> aren't always delete
commands; when given arguments, they kill instead, since they can erase
more than one character this way.
The other delete commands are those which delete only whitespace
characters: spaces, tabs and newlines. `M-\'
(`delete-horizontal-space') deletes all the spaces and tab characters
before and after point. `M-<SPC>' (`just-one-space') does likewise but
leaves a single space after point, regardless of the number of spaces
that existed previously (even zero).
`C-x C-o' (`delete-blank-lines') deletes all blank lines after the
current line. If the current line is blank, it deletes all blank lines
preceding the current line as well (leaving one blank line, the current
line).
`M-^' (`delete-indentation') joins the current line and the previous
line, by deleting a newline and all surrounding spaces, usually leaving
a single space. *Note M-^: Indentation.
Killing by Lines
----------------
`C-k'
Kill rest of line or one or more lines (`kill-line').
The simplest kill command is `C-k'. If given at the beginning of a
line, it kills all the text on the line, leaving it blank. When used
on a blank line, it kills the whole line including its newline. To kill
an entire non-blank line, go to the beginning and type `C-k' twice.
More generally, `C-k' kills from point up to the end of the line,
unless it is at the end of a line. In that case it kills the newline
following point, thus merging the next line into the current one.
Spaces and tabs that you can't see at the end of the line are ignored
when deciding which case applies, so if point appears to be at the end
of the line, you can be sure `C-k' will kill the newline.
When `C-k' is given a positive argument, it kills that many lines
and the newlines that follow them (however, text on the current line
before point is spared). With a negative argument -N, it kills N lines
preceding the current line (together with the text on the current line
before point). Thus, `C-u - 2 C-k' at the front of a line kills the
two previous lines.
`C-k' with an argument of zero kills the text before point on the
current line.
If the variable `kill-whole-line' is non-`nil', `C-k' at the very
beginning of a line kills the entire line including the following
newline. This variable is normally `nil'.
Other Kill Commands
-------------------
`C-w'
Kill region (from point to the mark) (`kill-region').
`M-d'
Kill word (`kill-word'). *Note Words::.
`M-<DEL>'
Kill word backwards (`backward-kill-word').
`C-x <DEL>'
Kill back to beginning of sentence (`backward-kill-sentence').
*Note Sentences::.
`M-k'
Kill to end of sentence (`kill-sentence').
`C-M-k'
Kill sexp (`kill-sexp'). *Note Lists::.
`M-z CHAR'
Kill through the next occurrence of CHAR (`zap-to-char').
A kill command which is very general is `C-w' (`kill-region'), which
kills everything between point and the mark. With this command, you
can kill any contiguous sequence of characters, if you first set the
region around them.
A convenient way of killing is combined with searching: `M-z'
(`zap-to-char') reads a character and kills from point up to (and
including) the next occurrence of that character in the buffer. A
numeric argument acts as a repeat count. A negative argument means to
search backward and kill text before point.
Other syntactic units can be killed: words, with `M-<DEL>' and `M-d'
(*note Words::.); sexps, with `C-M-k' (*note Lists::.); and sentences,
with `C-x <DEL>' and `M-k' (*note Sentences::.).
You can use kill commands in read-only buffers. They don't actually
change the buffer, and they beep to warn you of that, but they do copy
the text you tried to kill into the kill ring, so you can yank it into
other buffers. Most of the kill commands move point across the text
they copy in this way, so that successive kill commands build up a
single kill ring entry as usual.
Yanking
=======
"Yanking" means reinserting text previously killed. This is what
some systems call "pasting." The usual way to move or copy text is to
kill it and then yank it elsewhere one or more times.
`C-y'
Yank last killed text (`yank').
`M-y'
Replace text just yanked with an earlier batch of killed text
(`yank-pop').
`M-w'
Save region as last killed text without actually killing it
(`kill-ring-save').
`C-M-w'
Append next kill to last batch of killed text (`append-next-kill').
The Kill Ring
-------------
All killed text is recorded in the "kill ring", a list of blocks of
text that have been killed. There is only one kill ring, shared by all
buffers, so you can kill text in one buffer and yank it in another
buffer. This is the usual way to move text from one file to another.
(*Note Accumulating Text::, for some other ways.)
The command `C-y' (`yank') reinserts the text of the most recent
kill. It leaves the cursor at the end of the text. It sets the mark at
the beginning of the text. *Note Mark::.
`C-u C-y' leaves the cursor in front of the text, and sets the mark
after it. This happens only if the argument is specified with just a
`C-u', precisely. Any other sort of argument, including `C-u' and
digits, specifies an earlier kill to yank (*note Earlier Kills::.).
To copy a block of text, you can use `M-w' (`kill-ring-save'), which
copies the region into the kill ring without removing it from the
buffer. This is approximately equivalent to `C-w' followed by `C-x u',
except that `M-w' does not alter the undo history and does not
temporarily change the screen.
Appending Kills
---------------
Normally, each kill command pushes a new entry onto the kill ring.
However, two or more kill commands in a row combine their text into a
single entry, so that a single `C-y' yanks all the text as a unit, just
as it was before it was killed.
Thus, if you want to yank text as a unit, you need not kill all of it
with one command; you can keep killing line after line, or word after
word, until you have killed it all, and you can still get it all back at
once.
Commands that kill forward from point add onto the end of the
previous killed text. Commands that kill backward from point add text
onto the beginning. This way, any sequence of mixed forward and
backward kill commands puts all the killed text into one entry without
rearrangement. Numeric arguments do not break the sequence of
appending kills. For example, suppose the buffer contains this text:
This is a line -!-of sample text.
with point shown by -!-. If you type `M-d M-<DEL> M-d M-<DEL>',
killing alternately forward and backward, you end up with `a line of
sample' as one entry in the kill ring, and `This is text.' in the
buffer. (Note the double space, which you can clean up with `M-<SPC>'
or `M-q'.)
Another way to kill the same text is to move back two words with
`M-b M-b', then kill all four words forward with `C-u M-d'. This
produces exactly the same results in the buffer and in the kill ring.
`M-f M-f C-u M-<DEL>' kills the same text, all going backward; once
again, the result is the same. The text in the kill ring entry always
has the same order that it had in the buffer before you killed it.
If a kill command is separated from the last kill command by other
commands (not just numeric arguments), it starts a new entry on the kill
ring. But you can force it to append by first typing the command
`C-M-w' (`append-next-kill') right before it. The `C-M-w' tells the
following command, if it is a kill command, to append the text it kills
to the last killed text, instead of starting a new entry. With
`C-M-w', you can kill several separated pieces of text and accumulate
them to be yanked back in one place.
A kill command following `M-w' does not append to the text that
`M-w' copied into the kill ring.
Yanking Earlier Kills
---------------------
To recover killed text that is no longer the most recent kill, use
the `M-y' command (`yank-pop'). It takes the text previously yanked
and replaces it with the text from an earlier kill. So, to recover the
text of the next-to-the-last kill, first use `C-y' to yank the last
kill, and then use `M-y' to replace it with the previous kill. `M-y'
is allowed only after a `C-y' or another `M-y'.
You can understand `M-y' in terms of a "last yank" pointer which
points at an entry in the kill ring. Each time you kill, the "last
yank" pointer moves to the newly made entry at the front of the ring.
`C-y' yanks the entry which the "last yank" pointer points to. `M-y'
moves the "last yank" pointer to a different entry, and the text in the
buffer changes to match. Enough `M-y' commands can move the pointer to
any entry in the ring, so you can get any entry into the buffer.
Eventually the pointer reaches the end of the ring; the next `M-y'
moves it to the first entry again.
`M-y' moves the "last yank" pointer around the ring, but it does not
change the order of the entries in the ring, which always runs from the
most recent kill at the front to the oldest one still remembered.
`M-y' can take a numeric argument, which tells it how many entries
to advance the "last yank" pointer by. A negative argument moves the
pointer toward the front of the ring; from the front of the ring, it
moves "around" to the last entry and continues forward from there.
Once the text you are looking for is brought into the buffer, you can
stop doing `M-y' commands and it will stay there. It's just a copy of
the kill ring entry, so editing it in the buffer does not change what's
in the ring. As long as no new killing is done, the "last yank"
pointer remains at the same place in the kill ring, so repeating `C-y'
will yank another copy of the same previous kill.
If you know how many `M-y' commands it would take to find the text
you want, you can yank that text in one step using `C-y' with a numeric
argument. `C-y' with an argument restores the text the specified
number of entries back in the kill ring. Thus, `C-u 2 C-y' gets the
next-to-the-last block of killed text. It is equivalent to `C-y M-y'.
`C-y' with a numeric argument starts counting from the "last yank"
pointer, and sets the "last yank" pointer to the entry that it yanks.
The length of the kill ring is controlled by the variable
`kill-ring-max'; no more than that many blocks of killed text are saved.
The actual contents of the kill ring are stored in a variable named
`kill-ring'; you can view the entire contents of the kill ring with the
command `C-h v kill-ring'.
Accumulating Text
=================
Usually we copy or move text by killing it and yanking it, but there
are other methods convenient for copying one block of text in many
places, or for copying many scattered blocks of text into one place. To
copy one block to many places, store it in a register (*note
Registers::.). Here we describe the commands to accumulate scattered
pieces of text into a buffer or into a file.
`M-x append-to-buffer'
Append region to contents of specified buffer.
`M-x prepend-to-buffer'
Prepend region to contents of specified buffer.
`M-x copy-to-buffer'
Copy region into specified buffer, deleting that buffer's old
contents.
`M-x insert-buffer'
Insert contents of specified buffer into current buffer at point.
`M-x append-to-file'
Append region to contents of specified file, at the end.
To accumulate text into a buffer, use `M-x append-to-buffer'. This
reads a buffer name, then inserts a copy of the region into the buffer
specified. If you specify a nonexistent buffer, `append-to-buffer'
creates the buffer. The text is inserted wherever point is in that
buffer. If you have been using the buffer for editing, the copied text
goes into the middle of the text of the buffer, wherever point happens
to be in it.
Point in that buffer is left at the end of the copied text, so
successive uses of `append-to-buffer' accumulate the text in the
specified buffer in the same order as they were copied. Strictly
speaking, `append-to-buffer' does not always append to the text already
in the buffer--it appends only if point in that buffer is at the end.
However, if `append-to-buffer' is the only command you use to alter a
buffer, then point is always at the end.
`M-x prepend-to-buffer' is just like `append-to-buffer' except that
point in the other buffer is left before the copied text, so successive
prependings add text in reverse order. `M-x copy-to-buffer' is similar
except that any existing text in the other buffer is deleted, so the
buffer is left containing just the text newly copied into it.
To retrieve the accumulated text from another buffer, use the command
`M-x insert-buffer'; this too takes BUFFERNAME as an argument. It
inserts a copy of the text in buffer BUFFERNAME into the selected
buffer. You can alternatively select the other buffer for editing,
then optionally move text from it by killing. *Note Buffers::, for
background information on buffers.
Instead of accumulating text within Emacs, in a buffer, you can
append text directly into a file with `M-x append-to-file', which takes
FILENAME as an argument. It adds the text of the region to the end of
the specified file. The file is changed immediately on disk.
You should use `append-to-file' only with files that are *not* being
visited in Emacs. Using it on a file that you are editing in Emacs
would change the file behind Emacs's back, which can lead to losing
some of your editing.
Rectangles
==========
The rectangle commands operate on rectangular areas of the text: all
the characters between a certain pair of columns, in a certain range of
lines. Commands are provided to kill rectangles, yank killed
rectangles, clear them out, fill them with blanks or text, or delete
them. Rectangle commands are useful with text in multicolumn formats,
and for changing text into or out of such formats.
When you must specify a rectangle for a command to work on, you do it
by putting the mark at one corner and point at the opposite corner. The
rectangle thus specified is called the "region-rectangle" because you
control it in about the same way the region is controlled. But
remember that a given combination of point and mark values can be
interpreted either as a region or as a rectangle, depending on the
command that uses them.
If point and the mark are in the same column, the rectangle they
delimit is empty. If they are in the same line, the rectangle is one
line high. This asymmetry between lines and columns comes about
because point (and likewise the mark) is between two columns, but within
a line.
`C-x r k'
Kill the text of the region-rectangle, saving its contents as the
"last killed rectangle" (`kill-rectangle').
`C-x r d'
Delete the text of the region-rectangle (`delete-rectangle').
`C-x r y'
Yank the last killed rectangle with its upper left corner at point
(`yank-rectangle').
`C-x r o'
Insert blank space to fill the space of the region-rectangle
(`open-rectangle'). This pushes the previous contents of the
region-rectangle rightward.
`M-x clear-rectangle'
Clear the region-rectangle by replacing its contents with spaces.
`M-x delete-whitespace-rectangle'
Delete whitespace in each of the lines on the specified rectangle,
starting from the left edge column of the rectangle.
`C-x r t STRING <RET>'
Insert STRING on each line of the region-rectangle
(`string-rectangle').
The rectangle operations fall into two classes: commands deleting and
inserting rectangles, and commands for blank rectangles.
There are two ways to get rid of the text in a rectangle: you can
discard the text (delete it) or save it as the "last killed" rectangle.
The commands for these two ways are `C-x r d' (`delete-rectangle') and
`C-x r k' (`kill-rectangle'). In either case, the portion of each line
that falls inside the rectangle's boundaries is deleted, causing
following text (if any) on the line to move left into the gap.
Note that "killing" a rectangle is not killing in the usual sense;
the rectangle is not stored in the kill ring, but in a special place
that can only record the most recent rectangle killed. This is because
yanking a rectangle is so different from yanking linear text that
different yank commands have to be used and yank-popping is hard to
make sense of.
To yank the last killed rectangle, type `C-x r y'
(`yank-rectangle'). Yanking a rectangle is the opposite of killing
one. Point specifies where to put the rectangle's upper left corner.
The rectangle's first line is inserted there, the rectangle's second
line is inserted at a position one line vertically down, and so on. The
number of lines affected is determined by the height of the saved
rectangle.
You can convert single-column lists into double-column lists using
rectangle killing and yanking; kill the second half of the list as a
rectangle and then yank it beside the first line of the list. *Note
Two-Column::, for another way to edit multi-column text.
You can also copy rectangles into and out of registers with `C-x r r
R' and `C-x r i R'. *Note Rectangle Registers: RegRect.
There are two commands you can use for making blank rectangles: `M-x
clear-rectangle' which blanks out existing text, and `C-x r o'
(`open-rectangle') which inserts a blank rectangle. Clearing a
rectangle is equivalent to deleting it and then inserting a blank
rectangle of the same size.
The command `M-x delete-whitespace-rectangle' deletes horizontal
whitespace starting from a particular column. This applies to each of
the lines in the rectangle, and the column is specified by the left
edge of the rectangle. The right edge of the rectangle does not make
any difference to this command.
The command `C-x r t' (`M-x string-rectangle') replaces the
rectangle with a specified string (inserted once on each line). The
string's width need not be the same as the width of the rectangle. If
the string's width is less, the text after the rectangle shifts left; if
the string is wider than the rectangle, the text after the rectangle
shifts right.
Registers
*********
Emacs "registers" are places you can save text or positions for
later use. Once you save text or a rectangle in a register, you can
copy it into the buffer once or many times; you can move point to a
position saved in a register once or many times.
Each register has a name which is a single character. A register can
store a piece of text, a rectangle, a position, a window configuration,
or a file name, but only one thing at any given time. Whatever you
store in a register remains there until you store something else in that
register. To see what a register R contains, use `M-x view-register'.
`M-x view-register <RET> R'
Display a description of what register R contains.
Saving Positions in Registers
=============================
Saving a position records a place in a buffer so that you can move
back there later. Moving to a saved position switches to that buffer
and moves point to that place in it.
`C-x r <SPC> R'
Save position of point in register R (`point-to-register').
`C-x r j R'
Jump to the position saved in register R (`jump-to-register').
To save the current position of point in a register, choose a name R
and type `C-x r <SPC> R'. The register R retains the position thus
saved until you store something else in that register.
The command `C-x r j R' moves point to the position recorded in
register R. The register is not affected; it continues to record the
same position. You can jump to the saved position any number of times.
If you use `C-x r j' to go to a saved position, but the buffer it
was saved from has been killed, `C-x r j' tries to create the buffer
again by visiting the same file. Of course, this works only for buffers
that were visiting files.
Saving Text in Registers
========================
When you want to insert a copy of the same piece of text several
times, it may be inconvenient to yank it from the kill ring, since each
subsequent kill moves that entry further down the ring. An alternative
is to store the text in a register and later retrieve it.
`C-x r s R'
Copy region into register R (`copy-to-register').
`C-x r i R'
Insert text from register R (`insert-register').
`C-x r s R' stores a copy of the text of the region into the
register named R. Given a numeric argument, `C-x r s R' deletes the
text from the buffer as well.
`C-x r i R' inserts in the buffer the text from register R.
Normally it leaves point before the text and places the mark after, but
with a numeric argument (`C-u') it puts point after the text and the
mark before.
Saving Rectangles in Registers
==============================
A register can contain a rectangle instead of linear text. The
rectangle is represented as a list of strings. *Note Rectangles::, for
basic information on how to specify a rectangle in the buffer.
`C-x r r R'
Copy the region-rectangle into register R
(`copy-rectangle-to-register'). With numeric argument, delete it
as well.
`C-x r i R'
Insert the rectangle stored in register R (if it contains a
rectangle) (`insert-register').
The `C-x r i R' command inserts a text string if the register
contains one, and inserts a rectangle if the register contains one.
See also the command `sort-columns', which you can think of as
sorting a rectangle. *Note Sorting::.
Saving Window Configurations in Registers
=========================================
You can save the window configuration of the selected frame in a
register, or even the configuration of all windows in all frames, and
restore the configuration later.
`C-x r w R'
Save the state of the selected frame's windows in register R
(`window-configuration-to-register').
`C-x r f R'
Save the state of all frames, including all their windows, in
register R (`frame-configuration-to-register').
Use `C-x r j R' to restore a window or frame configuration. This is
the same command used to restore a cursor position. When you restore a
frame configuration, any existing frames not included in the
configuration become invisible. If you wish to delete these frames
instead, use `C-u C-x r j R'.
Keeping Numbers in Registers
============================
There are commands to store a number in a register, to insert the
number in the buffer in decimal, and to increment it. These commands
can be useful in keyboard macros (*note Keyboard Macros::.).
`C-u NUMBER C-x r n REG'
Store NUMBER into register REG (`number-to-register').
`C-u NUMBER C-x r + REG'
Increment the number in register REG by NUMBER
(`increment-register').
`C-x r g REG'
Insert the number from register REG into the buffer.
`C-x r g' is the same command used to insert any other sort of
register contents into the buffer.
Keeping File Names in Registers
===============================
If you visit certain file names frequently, you can visit them more
conveniently if you put their names in registers. Here's the Lisp code
used to put a file name in a register:
(set-register ?R '(file . NAME))
For example,
(set-register ?z '(file . "/gd/gnu/emacs/19.0/src/ChangeLog"))
puts the file name shown in register `z'.
To visit the file whose name is in register R, type `C-x r j R'.
(This is the same command used to jump to a position or restore a frame
configuration.)
Bookmarks
=========
"Bookmarks" are somewhat like registers in that they record
positions you can jump to. Unlike registers, they have long names, and
they persist automatically from one Emacs session to the next. The
prototypical use of bookmarks is to record "where you were reading" in
various files.
`C-x r m <RET>'
Set the bookmark for the visited file, at point.
`C-x r m BOOKMARK <RET>'
Set the bookmark named BOOKMARK at point (`bookmark-set').
`C-x r b BOOKMARK <RET>'
Jump to the bookmark named BOOKMARK (`bookmark-jump').
`C-x r l'
List all bookmarks (`list-bookmarks').
`M-x bookmark-save'
Save all the current bookmark values in the default bookmark file.
The prototypical use for bookmarks is to record one current position
in each of several files. So the command `C-x r m', which sets a
bookmark, uses the visited file name as the default for the bookmark
name. If you name each bookmark after the file it points to, then you
can conveniently revisit any of those files with `C-x r b', and move to
the position of the bookmark at the same time.
To display a list of all your bookmarks in a separate buffer, type
`C-x r l' (`list-bookmarks'). If you switch to that buffer, you can
use it to edit your bookmark definitions or annotate the bookmarks.
Type `C-h m' in that buffer for more information about its special
editing commands.
When you kill Emacs, Emacs offers to save your bookmark values in
your default bookmark file, `~/.emacs.bmk', if you have changed any
bookmark values. You can also save the bookmarks at any time with the
`M-x bookmark-save' command. The bookmark commands load your default
bookmark file automatically. This saving and loading is how bookmarks
persist from one Emacs session to the next.
If you set the variable `bookmark-save-flag' to 1, then each command
that sets a bookmark will also save your bookmarks; this way, you don't
lose any bookmark values even if Emacs crashes. (The value, if a
number, says how many bookmark modifications should go by between
saving.)
Bookmark position values are saved with surrounding context, so that
`bookmark-jump' can find the proper position even if the file is
modified slightly. The variable `bookmark-search-size' says how many
characters of context to record, on each side of the bookmark's
position.
Here are some additional commands for working with bookmarks:
`M-x bookmark-load <RET> FILENAME <RET>'
Load a file named FILENAME that contains a list of bookmark
values. You can use this command, as well as `bookmark-write', to
work with other files of bookmark values in addition to your
default bookmark file.
`M-x bookmark-write <RET> FILENAME <RET>'
Save all the current bookmark values in the file FILENAME.
`M-x bookmark-delete <RET> BOOKMARK <RET>'
Delete the bookmark named BOOKMARK.
`M-x bookmark-insert-location <RET> BOOKMARK <RET>'
Insert in the buffer the name of the file that bookmark BOOKMARK
points to.
`M-x bookmark-insert <RET> BOOKMARK <RET>'
Insert in the buffer the *contents* of the file that bookmark
BOOKMARK points to.
Controlling the Display
***********************
Since only part of a large buffer fits in the window, Emacs tries to
show a part that is likely to be interesting. Display-control commands
allow you to specify which part of the text you want to see, and how to
display it.
Scrolling
=========
If a buffer contains text that is too large to fit entirely within a
window that is displaying the buffer, Emacs shows a contiguous portion
of the text. The portion shown always contains point.
"Scrolling" means moving text up or down in the window so that
different parts of the text are visible. Scrolling forward means that
text moves up, and new text appears at the bottom. Scrolling backward
moves text down and new text appears at the top.
Scrolling happens automatically if you move point past the bottom or
top of the window. You can also explicitly request scrolling with the
commands in this section.
`C-l'
Clear screen and redisplay, scrolling the selected window to center
point vertically within it (`recenter').
`C-v'
Scroll forward (a windowful or a specified number of lines)
(`scroll-up').
`<NEXT>'
Likewise, scroll forward.
`M-v'
Scroll backward (`scroll-down').
`<PRIOR>'
Likewise, scroll backward.
`ARG C-l'
Scroll so point is on line ARG (`recenter').
`C-M-l'
Scroll heuristically to bring useful information onto the screen
(`reposition-window').
The most basic scrolling command is `C-l' (`recenter') with no
argument. It clears the entire screen and redisplays all windows. In
addition, it scrolls the selected window so that point is halfway down
from the top of the window.
The scrolling commands `C-v' and `M-v' let you move all the text in
the window up or down a few lines. `C-v' (`scroll-up') with an
argument shows you that many more lines at the bottom of the window,
moving the text and point up together as `C-l' might. `C-v' with a
negative argument shows you more lines at the top of the window. `M-v'
(`scroll-down') is like `C-v', but moves in the opposite direction.
The function keys <NEXT> and <PRIOR> are equivalent to `C-v' and `M-v'.
The names of scroll commands are based on the direction that the text
moves in the window. Thus, the command to scroll forward is called
`scroll-up' because it moves the text upward on the screen.
To read the buffer a windowful at a time, use `C-v' with no argument.
It takes the last two lines at the bottom of the window and puts them at
the top, followed by nearly a whole windowful of lines not previously
visible. If point was in the text scrolled off the top, it moves to the
new top of the window. `M-v' with no argument moves backward with
overlap similarly. The number of lines of overlap across a `C-v' or
`M-v' is controlled by the variable `next-screen-context-lines'; by
default, it is 2.
Some users like the full-screen scroll commands to keep point at the
same screen line. To enable this behavior, set the variable
`scroll-preserve-screen-position' to a non-`nil' value. This mode is
convenient for browsing through a file by scrolling by screenfuls; if
you come back to the screen where you started, point goes back to the
line where it started. However, this mode is inconvenient when you
move to the next screen in order to move point to the text there.
Another way to do scrolling is with `C-l' with a numeric argument.
`C-l' does not clear the screen when given an argument; it only scrolls
the selected window. With a positive argument N, it repositions text
to put point N lines down from the top. An argument of zero puts point
on the very top line. Point does not move with respect to the text;
rather, the text and point move rigidly on the screen. `C-l' with a
negative argument puts point that many lines from the bottom of the
window. For example, `C-u - 1 C-l' puts point on the bottom line, and
`C-u - 5 C-l' puts it five lines from the bottom. Just `C-u' as
argument, as in `C-u C-l', scrolls point to the center of the selected
window.
The `C-M-l' command (`reposition-window') scrolls the current window
heuristically in a way designed to get useful information onto the
screen. For example, in a Lisp file, this command tries to get the
entire current defun onto the screen if possible.
Scrolling happens automatically if point has moved out of the visible
portion of the text when it is time to display. Normally, automatic
scrolling centers point vertically within the window. However, if you
set `scroll-conservatively' to a small number N, then if you move point
just a little off the screen--less than N lines--then Emacs scrolls the
text just far enough to bring point back on screen. By default,
`scroll-conservatively' is 0.
The variable `scroll-margin' restricts how close point can come to
the top or bottom of a window. Its value is a number of screen lines;
if point comes within that many lines of the top or bottom of the
window, Emacs recenters the window. By default, `scroll-margin' is 0.
Horizontal Scrolling
====================
"Horizontal scrolling" means shifting all the lines sideways within
a window--so that some of the text near the left margin is not
displayed at all.
`C-x <'
Scroll text in current window to the left (`scroll-left').
`C-x >'
Scroll to the right (`scroll-right').
When a window has been scrolled horizontally, text lines are
truncated rather than continued (*note Continuation Lines::.), with a
`$' appearing in the first column when there is text truncated to the
left, and in the last column when there is text truncated to the right.
The command `C-x <' (`scroll-left') scrolls the selected window to
the left by N columns with argument N. This moves part of the
beginning of each line off the left edge of the window. With no
argument, it scrolls by almost the full width of the window (two
columns less, to be precise).
`C-x >' (`scroll-right') scrolls similarly to the right. The window
cannot be scrolled any farther to the right once it is displayed
normally (with each line starting at the window's left margin);
attempting to do so has no effect. This means that you don't have to
calculate the argument precisely for `C-x >'; any sufficiently large
argument will restore the normal display.
You can request automatic horizontal scrolling by enabling Hscroll
mode. When this mode is enabled, Emacs scrolls a window horizontally
whenever that is necessary to keep point visible and not too far from
the left or right edge. The command to enable or disable this mode is
`M-x hscroll-mode'.
Follow Mode
===========
"Follow mode" is a minor mode that makes two windows showing the
same buffer scroll as one tall "virtual window." To use Follow mode,
go to a frame with just one window, split it into two side-by-side
windows using `C-x 3', and then type `M-x follow-mode'. From then on,
you can edit the buffer in either of the two windows, or scroll either
one; the other window follows it.
To turn off Follow mode, type `M-x follow-mode' a second time.
Selective Display
=================
Emacs has the ability to hide lines indented more than a certain
number of columns (you specify how many columns). You can use this to
get an overview of a part of a program.
To hide lines, type `C-x $' (`set-selective-display') with a numeric
argument N. Then lines with at least N columns of indentation
disappear from the screen. The only indication of their presence is
that three dots (`...') appear at the end of each visible line that is
followed by one or more hidden ones.
The commands `C-n' and `C-p' move across the hidden lines as if they
were not there.
The hidden lines are still present in the buffer, and most editing
commands see them as usual, so you may find point in the middle of the
hidden text. When this happens, the cursor appears at the end of the
previous line, after the three dots. If point is at the end of the
visible line, before the newline that ends it, the cursor appears before
the three dots.
To make all lines visible again, type `C-x $' with no argument.
If you set the variable `selective-display-ellipses' to `nil', the
three dots do not appear at the end of a line that precedes hidden
lines. Then there is no visible indication of the hidden lines. This
variable becomes local automatically when set.
Optional Mode Line Features
===========================
The current line number of point appears in the mode line when Line
Number mode is enabled. Use the command `M-x line-number-mode' to turn
this mode on and off; normally it is on. The line number appears
before the buffer percentage POS, with the letter `L' to indicate what
it is. *Note Minor Modes::, for more information about minor modes and
about how to use this command.
If the buffer is very large (larger than the value of
`line-number-display-limit'), then the line number doesn't appear.
Emacs doesn't compute the line number when the buffer is large, because
that would be too slow. If you have narrowed the buffer (*note
Narrowing::.), the displayed line number is relative to the accessible
portion of the buffer.
You can also display the current column number by turning on Column
Number mode. It displays the current column number preceded by the
letter `C'. Type `M-x column-number-mode' to toggle this mode.
Emacs can optionally display the time and system load in all mode
lines. To enable this feature, type `M-x display-time'. The
information added to the mode line usually appears after the buffer
name, before the mode names and their parentheses. It looks like this:
HH:MMpm L.LL
Here HH and MM are the hour and minute, followed always by `am' or
`pm'. L.LL is the average number of running processes in the whole
system recently. (Some fields may be missing if your operating system
cannot support them.) If you prefer time display in 24-hour format,
set the variable `display-time-24hr-format' to `t'.
The word `Mail' appears after the load level if there is mail for
you that you have not read yet.
How Text Is Displayed
=====================
ASCII printing characters (octal codes 040 through 0176) in Emacs
buffers are displayed with their graphics. So are non-ASCII multibyte
printing characters (octal codes above 0400).
Some ASCII control characters are displayed in special ways. The
newline character (octal code 012) is displayed by starting a new line.
The tab character (octal code 011) is displayed by moving to the next
tab stop column (normally every 8 columns).
Other ASCII control characters are normally displayed as a caret
(`^') followed by the non-control version of the character; thus,
control-A is displayed as `^A'.
Non-ASCII characters 0200 through 0377 are displayed with octal
escape sequences; thus, character code 0243 (octal) is displayed as
`\243'. However, if you enable European display, most of these
characters become non-ASCII printing characters, and are displayed using
their graphics (assuming your terminal supports them). *Note
Single-Byte European Support::.
Variables Controlling Display
=============================
This section contains information for customization only. Beginning
users should skip it.
The variable `mode-line-inverse-video' controls whether the mode
line is displayed in inverse video (assuming the terminal supports it);
`nil' means don't do so. *Note Mode Line::. If you specify the
foreground color for the `modeline' face, and `mode-line-inverse-video'
is non-`nil', then the default background color for that face is the
usual foreground color. *Note Faces::.
If the variable `inverse-video' is non-`nil', Emacs attempts to
invert all the lines of the display from what they normally are.
If the variable `visible-bell' is non-`nil', Emacs attempts to make
the whole screen blink when it would normally make an audible bell
sound. This variable has no effect if your terminal does not have a way
to make the screen blink.
When you reenter Emacs after suspending, Emacs normally clears the
screen and redraws the entire display. On some terminals with more than
one page of memory, it is possible to arrange the termcap entry so that
the `ti' and `te' strings (output to the terminal when Emacs is entered
and exited, respectively) switch between pages of memory so as to use
one page for Emacs and another page for other output. Then you might
want to set the variable `no-redraw-on-reenter' non-`nil'; this tells
Emacs to assume, when resumed, that the screen page it is using still
contains what Emacs last wrote there.
The variable `echo-keystrokes' controls the echoing of
multi-character keys; its value is the number of seconds of pause
required to cause echoing to start, or zero meaning don't echo at all.
*Note Echo Area::.
If the variable `ctl-arrow' is `nil', control characters in the
buffer are displayed with octal escape sequences, except for newline
and tab. Altering the value of `ctl-arrow' makes it local to the
current buffer; until that time, the default value is in effect. The
default is initially `t'. *Note Display Tables: (elisp)Display Tables.
Normally, a tab character in the buffer is displayed as whitespace
which extends to the next display tab stop position, and display tab
stops come at intervals equal to eight spaces. The number of spaces
per tab is controlled by the variable `tab-width', which is made local
by changing it, just like `ctl-arrow'. Note that how the tab character
in the buffer is displayed has nothing to do with the definition of
<TAB> as a command. The variable `tab-width' must have an integer
value between 1 and 1000, inclusive.
If the variable `truncate-lines' is non-`nil', then each line of
text gets just one screen line for display; if the text line is too
long, display shows only the part that fits. If `truncate-lines' is
`nil', then long text lines display as more than one screen line,
enough to show the whole text of the line. *Note Continuation Lines::.
Altering the value of `truncate-lines' makes it local to the current
buffer; until that time, the default value is in effect. The default
is initially `nil'.
If the variable `truncate-partial-width-windows' is non-`nil', it
forces truncation rather than continuation in any window less than the
full width of the screen or frame, regardless of the value of
`truncate-lines'. For information about side-by-side windows, see
*Note Split Window::. See also *Note Display: (elisp)Display.
The variable `baud-rate' holds the output speed of the terminal, as
far as Emacs knows. Setting this variable does not change the speed of
actual data transmission, but the value is used for calculations such
as padding. It also affects decisions about whether to scroll part of
the screen or redraw it instead--even when using a window system. (We
designed it this way, despite the fact that a window system has no true
"output speed," to give you a way to tune these decisions.)
You can customize the way any particular character code is displayed
by means of a display table. *Note Display Tables: (elisp)Display
Tables.
Searching and Replacement
*************************
Like other editors, Emacs has commands for searching for occurrences
of a string. The principal search command is unusual in that it is
"incremental"; it begins to search before you have finished typing the
search string. There are also nonincremental search commands more like
those of other editors.
Besides the usual `replace-string' command that finds all
occurrences of one string and replaces them with another, Emacs has a
fancy replacement command called `query-replace' which asks
interactively which occurrences to replace.
Incremental Search
==================
An incremental search begins searching as soon as you type the first
character of the search string. As you type in the search string, Emacs
shows you where the string (as you have typed it so far) would be
found. When you have typed enough characters to identify the place you
want, you can stop. Depending on what you plan to do next, you may or
may not need to terminate the search explicitly with <RET>.
`C-s'
Incremental search forward (`isearch-forward').
`C-r'
Incremental search backward (`isearch-backward').
`C-s' starts an incremental search. `C-s' reads characters from the
keyboard and positions the cursor at the first occurrence of the
characters that you have typed. If you type `C-s' and then `F', the
cursor moves right after the first `F'. Type an `O', and see the
cursor move to after the first `FO'. After another `O', the cursor is
after the first `FOO' after the place where you started the search. At
each step, the buffer text that matches the search string is
highlighted, if the terminal can do that; at each step, the current
search string is updated in the echo area.
If you make a mistake in typing the search string, you can cancel
characters with <DEL>. Each <DEL> cancels the last character of search
string. This does not happen until Emacs is ready to read another
input character; first it must either find, or fail to find, the
character you want to erase. If you do not want to wait for this to
happen, use `C-g' as described below.
When you are satisfied with the place you have reached, you can type
<RET>, which stops searching, leaving the cursor where the search
brought it. Also, any command not specially meaningful in searches
stops the searching and is then executed. Thus, typing `C-a' would
exit the search and then move to the beginning of the line. <RET> is
necessary only if the next command you want to type is a printing
character, <DEL>, <RET>, or another control character that is special
within searches (`C-q', `C-w', `C-r', `C-s', `C-y', `M-y', `M-r', or
`M-s').
Sometimes you search for `FOO' and find it, but not the one you
expected to find. There was a second `FOO' that you forgot about,
before the one you were aiming for. In this event, type another `C-s'
to move to the next occurrence of the search string. This can be done
any number of times. If you overshoot, you can cancel some `C-s'
characters with <DEL>.
After you exit a search, you can search for the same string again by
typing just `C-s C-s': the first `C-s' is the key that invokes
incremental search, and the second `C-s' means "search again."
To reuse earlier search strings, use the "search ring". The
commands `M-p' and `M-n' move through the ring to pick a search string
to reuse. These commands leave the selected search ring element in the
minibuffer, where you can edit it. Type `C-s' or `C-r' to terminate
editing the string and search for it.
If your string is not found at all, the echo area says `Failing
I-Search'. The cursor is after the place where Emacs found as much of
your string as it could. Thus, if you search for `FOOT', and there is
no `FOOT', you might see the cursor after the `FOO' in `FOOL'. At this
point there are several things you can do. If your string was
mistyped, you can rub some of it out and correct it. If you like the
place you have found, you can type <RET> or some other Emacs command to
"accept what the search offered." Or you can type `C-g', which removes
from the search string the characters that could not be found (the `T'
in `FOOT'), leaving those that were found (the `FOO' in `FOOT'). A
second `C-g' at that point cancels the search entirely, returning point
to where it was when the search started.
An upper-case letter in the search string makes the search
case-sensitive. If you delete the upper-case character from the search
string, it ceases to have this effect. *Note Search Case::.
If a search is failing and you ask to repeat it by typing another
`C-s', it starts again from the beginning of the buffer. Repeating a
failing reverse search with `C-r' starts again from the end. This is
called "wrapping around". `Wrapped' appears in the search prompt once
this has happened. If you keep on going past the original starting
point of the search, it changes to `Overwrapped', which means that you
are revisiting matches that you have already seen.
The `C-g' "quit" character does special things during searches; just
what it does depends on the status of the search. If the search has
found what you specified and is waiting for input, `C-g' cancels the
entire search. The cursor moves back to where you started the search.
If `C-g' is typed when there are characters in the search string that
have not been found--because Emacs is still searching for them, or
because it has failed to find them--then the search string characters
which have not been found are discarded from the search string. With
them gone, the search is now successful and waiting for more input, so
a second `C-g' will cancel the entire search.
To search for a newline, type `C-j'. To search for another control
character, such as control-S or carriage return, you must quote it by
typing `C-q' first. This function of `C-q' is analogous to its use for
insertion (*note Inserting Text::.): it causes the following character
to be treated the way any "ordinary" character is treated in the same
context. You can also specify a character by its octal code: enter
`C-q' followed by a sequence of octal digits.
You can change to searching backwards with `C-r'. If a search fails
because the place you started was too late in the file, you should do
this. Repeated `C-r' keeps looking for more occurrences backwards. A
`C-s' starts going forwards again. `C-r' in a search can be canceled
with <DEL>.
If you know initially that you want to search backwards, you can use
`C-r' instead of `C-s' to start the search, because `C-r' as a key runs
a command (`isearch-backward') to search backward. A backward search
finds matches that are entirely before the starting point, just as a
forward search finds matches that begin after it.
The characters `C-y' and `C-w' can be used in incremental search to
grab text from the buffer into the search string. This makes it
convenient to search for another occurrence of text at point. `C-w'
copies the word after point as part of the search string, advancing
point over that word. Another `C-s' to repeat the search will then
search for a string including that word. `C-y' is similar to `C-w' but
copies all the rest of the current line into the search string. Both
`C-y' and `C-w' convert the text they copy to lower case if the search
is currently not case-sensitive; this is so the search remains
case-insensitive.
The character `M-y' copies text from the kill ring into the search
string. It uses the same text that `C-y' as a command would yank.
*Note Yanking::.
When you exit the incremental search, it sets the mark to where point
*was*, before the search. That is convenient for moving back there.
In Transient Mark mode, incremental search sets the mark without
activating it, and does so only if the mark is not already active.
To customize the special characters that incremental search
understands, alter their bindings in the keymap `isearch-mode-map'.
For a list of bindings, look at the documentation of `isearch-mode' with
`C-h f isearch-mode <RET>'.
Slow Terminal Incremental Search
--------------------------------
Incremental search on a slow terminal uses a modified style of
display that is designed to take less time. Instead of redisplaying
the buffer at each place the search gets to, it creates a new
single-line window and uses that to display the line that the search
has found. The single-line window comes into play as soon as point
gets outside of the text that is already on the screen.
When you terminate the search, the single-line window is removed.
Then Emacs redisplays the window in which the search was done, to show
its new position of point.
The slow terminal style of display is used when the terminal baud
rate is less than or equal to the value of the variable
`search-slow-speed', initially 1200.
The number of lines to use in slow terminal search display is
controlled by the variable `search-slow-window-lines'. Its normal
value is 1.
Nonincremental Search
=====================
Emacs also has conventional nonincremental search commands, which
require you to type the entire search string before searching begins.
`C-s <RET> STRING <RET>'
Search for STRING.
`C-r <RET> STRING <RET>'
Search backward for STRING.
To do a nonincremental search, first type `C-s <RET>'. This enters
the minibuffer to read the search string; terminate the string with
<RET>, and then the search takes place. If the string is not found,
the search command gets an error.
The way `C-s <RET>' works is that the `C-s' invokes incremental
search, which is specially programmed to invoke nonincremental search
if the argument you give it is empty. (Such an empty argument would
otherwise be useless.) `C-r <RET>' also works this way.
However, nonincremental searches performed using `C-s <RET>' do not
call `search-forward' right away. The first thing done is to see if
the next character is `C-w', which requests a word search. *Note Word
Search::.
Forward and backward nonincremental searches are implemented by the
commands `search-forward' and `search-backward'. These commands may be
bound to keys in the usual manner. The feature that you can get to
them via the incremental search commands exists for historical reasons,
and to avoid the need to find suitable key sequences for them.
Word Search
===========
Word search searches for a sequence of words without regard to how
the words are separated. More precisely, you type a string of many
words, using single spaces to separate them, and the string can be
found even if there are multiple spaces, newlines or other punctuation
between the words.
Word search is useful for editing a printed document made with a text
formatter. If you edit while looking at the printed, formatted version,
you can't tell where the line breaks are in the source file. With word
search, you can search without having to know them.
`C-s <RET> C-w WORDS <RET>'
Search for WORDS, ignoring details of punctuation.
`C-r <RET> C-w WORDS <RET>'
Search backward for WORDS, ignoring details of punctuation.
Word search is a special case of nonincremental search and is invoked
with `C-s <RET> C-w'. This is followed by the search string, which
must always be terminated with <RET>. Being nonincremental, this
search does not start until the argument is terminated. It works by
constructing a regular expression and searching for that; see *Note
Regexp Search::.
Use `C-r <RET> C-w' to do backward word search.
Forward and backward word searches are implemented by the commands
`word-search-forward' and `word-search-backward'. These commands may
be bound to keys in the usual manner. The feature that you can get to
them via the incremental search commands exists for historical reasons,
and to avoid the need to find suitable key sequences for them.
Regular Expression Search
=========================
A "regular expression" ("regexp", for short) is a pattern that
denotes a class of alternative strings to match, possibly infinitely
many. In GNU Emacs, you can search for the next match for a regexp
either incrementally or not.
Incremental search for a regexp is done by typing `C-M-s'
(`isearch-forward-regexp'). This command reads a search string
incrementally just like `C-s', but it treats the search string as a
regexp rather than looking for an exact match against the text in the
buffer. Each time you add text to the search string, you make the
regexp longer, and the new regexp is searched for. Invoking `C-s' with
a prefix argument (its value does not matter) is another way to do a
forward incremental regexp search. To search backward for a regexp,
use `C-M-r' (`isearch-backward-regexp'), or `C-r' with a prefix
argument.
All of the control characters that do special things within an
ordinary incremental search have the same function in incremental regexp
search. Typing `C-s' or `C-r' immediately after starting the search
retrieves the last incremental search regexp used; that is to say,
incremental regexp and non-regexp searches have independent defaults.
They also have separate search rings that you can access with `M-p' and
`M-n'.
If you type <SPC> in incremental regexp search, it matches any
sequence of whitespace characters, including newlines. If you want to
match just a space, type `C-q <SPC>'.
Note that adding characters to the regexp in an incremental regexp
search can make the cursor move back and start again. For example, if
you have searched for `foo' and you add `\|bar', the cursor backs up in
case the first `bar' precedes the first `foo'.
Nonincremental search for a regexp is done by the functions
`re-search-forward' and `re-search-backward'. You can invoke these
with `M-x', or bind them to keys, or invoke them by way of incremental
regexp search with `C-M-s <RET>' and `C-M-r <RET>'.
If you use the incremental regexp search commands with a prefix
argument, they perform ordinary string search, like `isearch-forward'
and `isearch-backward'. *Note Incremental Search::.
Syntax of Regular Expressions
=============================
Regular expressions have a syntax in which a few characters are
special constructs and the rest are "ordinary". An ordinary character
is a simple regular expression which matches that same character and
nothing else. The special characters are `$', `^', `.', `*', `+', `?',
`[', `]' and `\'. Any other character appearing in a regular
expression is ordinary, unless a `\' precedes it.
For example, `f' is not a special character, so it is ordinary, and
therefore `f' is a regular expression that matches the string `f' and
no other string. (It does *not* match the string `ff'.) Likewise, `o'
is a regular expression that matches only `o'. (When case distinctions
are being ignored, these regexps also match `F' and `O', but we
consider this a generalization of "the same string," rather than an
exception.)
Any two regular expressions A and B can be concatenated. The result
is a regular expression which matches a string if A matches some amount
of the beginning of that string and B matches the rest of the string.
As a simple example, we can concatenate the regular expressions `f'
and `o' to get the regular expression `fo', which matches only the
string `fo'. Still trivial. To do something nontrivial, you need to
use one of the special characters. Here is a list of them.
`. (Period)'
is a special character that matches any single character except a
newline. Using concatenation, we can make regular expressions
like `a.b', which matches any three-character string that begins
with `a' and ends with `b'.
`*'
is not a construct by itself; it is a postfix operator that means
to match the preceding regular expression repetitively as many
times as possible. Thus, `o*' matches any number of `o's
(including no `o's).
`*' always applies to the *smallest* possible preceding
expression. Thus, `fo*' has a repeating `o', not a repeating
`fo'. It matches `f', `fo', `foo', and so on.
The matcher processes a `*' construct by matching, immediately, as
many repetitions as can be found. Then it continues with the rest
of the pattern. If that fails, backtracking occurs, discarding
some of the matches of the `*'-modified construct in case that
makes it possible to match the rest of the pattern. For example,
in matching `ca*ar' against the string `caaar', the `a*' first
tries to match all three `a's; but the rest of the pattern is `ar'
and there is only `r' left to match, so this try fails. The next
alternative is for `a*' to match only two `a's. With this choice,
the rest of the regexp matches successfully.
`+'
is a postfix operator, similar to `*' except that it must match
the preceding expression at least once. So, for example, `ca+r'
matches the strings `car' and `caaaar' but not the string `cr',
whereas `ca*r' matches all three strings.
`?'
is a postfix operator, similar to `*' except that it can match the
preceding expression either once or not at all. For example,
`ca?r' matches `car' or `cr'; nothing else.
`[ ... ]'
is a "character set", which begins with `[' and is terminated by
`]'. In the simplest case, the characters between the two
brackets are what this set can match.
Thus, `[ad]' matches either one `a' or one `d', and `[ad]*'
matches any string composed of just `a's and `d's (including the
empty string), from which it follows that `c[ad]*r' matches `cr',
`car', `cdr', `caddaar', etc.
You can also include character ranges in a character set, by
writing the starting and ending characters with a `-' between
them. Thus, `[a-z]' matches any lower-case ASCII letter. Ranges
may be intermixed freely with individual characters, as in
`[a-z$%.]', which matches any lower-case ASCII letter or `$', `%'
or period.
Note that the usual regexp special characters are not special
inside a character set. A completely different set of special
characters exists inside character sets: `]', `-' and `^'.
To include a `]' in a character set, you must make it the first
character. For example, `[]a]' matches `]' or `a'. To include a
`-', write `-' as the first or last character of the set, or put
it after a range. Thus, `[]-]' matches both `]' and `-'.
To include `^' in a set, put it anywhere but at the beginning of
the set.
When you use a range in case-insensitive search, you should write
both ends of the range in upper case, or both in lower case, or
both should be non-letters. The behavior of a mixed-case range
such as `A-z' is somewhat ill-defined, and it may change in future
Emacs versions.
`[^ ... ]'
`[^' begins a "complemented character set", which matches any
character except the ones specified. Thus, `[^a-z0-9A-Z]' matches
all characters *except* letters and digits.
`^' is not special in a character set unless it is the first
character. The character following the `^' is treated as if it
were first (in other words, `-' and `]' are not special there).
A complemented character set can match a newline, unless newline is
mentioned as one of the characters not to match. This is in
contrast to the handling of regexps in programs such as `grep'.
`^'
is a special character that matches the empty string, but only at
the beginning of a line in the text being matched. Otherwise it
fails to match anything. Thus, `^foo' matches a `foo' that occurs
at the beginning of a line.
`$'
is similar to `^' but matches only at the end of a line. Thus,
`x+$' matches a string of one `x' or more at the end of a line.
`\'
has two functions: it quotes the special characters (including
`\'), and it introduces additional special constructs.
Because `\' quotes special characters, `\$' is a regular
expression that matches only `$', and `\[' is a regular expression
that matches only `[', and so on.
Note: for historical compatibility, special characters are treated as
ordinary ones if they are in contexts where their special meanings make
no sense. For example, `*foo' treats `*' as ordinary since there is no
preceding expression on which the `*' can act. It is poor practice to
depend on this behavior; it is better to quote the special character
anyway, regardless of where it appears.
For the most part, `\' followed by any character matches only that
character. However, there are several exceptions: two-character
sequences starting with `\' that have special meanings. The second
character in the sequence is always an ordinary character when used on
its own. Here is a table of `\' constructs.
`\|'
specifies an alternative. Two regular expressions A and B with
`\|' in between form an expression that matches some text if
either A matches it or B matches it. It works by trying to match
A, and if that fails, by trying to match B.
Thus, `foo\|bar' matches either `foo' or `bar' but no other string.
`\|' applies to the largest possible surrounding expressions.
Only a surrounding `\( ... \)' grouping can limit the grouping
power of `\|'.
Full backtracking capability exists to handle multiple uses of
`\|'.
`\( ... \)'
is a grouping construct that serves three purposes:
1. To enclose a set of `\|' alternatives for other operations.
Thus, `\(foo\|bar\)x' matches either `foox' or `barx'.
2. To enclose a complicated expression for the postfix operators
`*', `+' and `?' to operate on. Thus, `ba\(na\)*' matches
`bananana', etc., with any (zero or more) number of `na'
strings.
3. To record a matched substring for future reference.
This last application is not a consequence of the idea of a
parenthetical grouping; it is a separate feature that is assigned
as a second meaning to the same `\( ... \)' construct. In practice
there is no conflict between the two meanings.
`\D'
matches the same text that matched the Dth occurrence of a `\( ...
\)' construct.
After the end of a `\( ... \)' construct, the matcher remembers
the beginning and end of the text matched by that construct. Then,
later on in the regular expression, you can use `\' followed by the
digit D to mean "match the same text matched the Dth time by the
`\( ... \)' construct."
The strings matching the first nine `\( ... \)' constructs
appearing in a regular expression are assigned numbers 1 through 9
in the order that the open-parentheses appear in the regular
expression. So you can use `\1' through `\9' to refer to the text
matched by the corresponding `\( ... \)' constructs.
For example, `\(.*\)\1' matches any newline-free string that is
composed of two identical halves. The `\(.*\)' matches the first
half, which may be anything, but the `\1' that follows must match
the same exact text.
If a particular `\( ... \)' construct matches more than once
(which can easily happen if it is followed by `*'), only the last
match is recorded.
`\`'
matches the empty string, but only at the beginning of the buffer
or string being matched against.
`\''
matches the empty string, but only at the end of the buffer or
string being matched against.
`\='
matches the empty string, but only at point.
`\b'
matches the empty string, but only at the beginning or end of a
word. Thus, `\bfoo\b' matches any occurrence of `foo' as a
separate word. `\bballs?\b' matches `ball' or `balls' as a
separate word.
`\b' matches at the beginning or end of the buffer regardless of
what text appears next to it.
`\B'
matches the empty string, but *not* at the beginning or end of a
word.
`\<'
matches the empty string, but only at the beginning of a word.
`\<' matches at the beginning of the buffer only if a
word-constituent character follows.
`\>'
matches the empty string, but only at the end of a word. `\>'
matches at the end of the buffer only if the contents end with a
word-constituent character.
`\w'
matches any word-constituent character. The syntax table
determines which characters these are. *Note Syntax::.
`\W'
matches any character that is not a word-constituent.
`\sC'
matches any character whose syntax is C. Here C is a character
that represents a syntax code: thus, `w' for word constituent, `-'
for whitespace, `(' for open parenthesis, etc. Represent a
character of whitespace (which can be a newline) by either `-' or
a space character.
`\SC'
matches any character whose syntax is not C.
The constructs that pertain to words and syntax are controlled by the
setting of the syntax table (*note Syntax::.).
Here is a complicated regexp, used by Emacs to recognize the end of a
sentence together with any whitespace that follows. It is given in Lisp
syntax to enable you to distinguish the spaces from the tab characters.
In Lisp syntax, the string constant begins and ends with a
double-quote. `\"' stands for a double-quote as part of the regexp,
`\\' for a backslash as part of the regexp, `\t' for a tab and `\n' for
a newline.
"[.?!][]\"')]*\\($\\|\t\\| \\)[ \t\n]*"
This contains four parts in succession: a character set matching period,
`?', or `!'; a character set matching close-brackets, quotes, or
parentheses, repeated any number of times; an alternative in
backslash-parentheses that matches end-of-line, a tab, or two spaces;
and a character set matching whitespace characters, repeated any number
of times.
To enter the same regexp interactively, you would type <TAB> to
enter a tab, and `C-j' to enter a newline. You would also type single
backslashes as themselves, instead of doubling them for Lisp syntax.
Searching and Case
==================
Incremental searches in Emacs normally ignore the case of the text
they are searching through, if you specify the text in lower case.
Thus, if you specify searching for `foo', then `Foo' and `foo' are also
considered a match. Regexps, and in particular character sets, are
included: `[ab]' would match `a' or `A' or `b' or `B'.
An upper-case letter anywhere in the incremental search string makes
the search case-sensitive. Thus, searching for `Foo' does not find
`foo' or `FOO'. This applies to regular expression search as well as
to string search. The effect ceases if you delete the upper-case
letter from the search string.
If you set the variable `case-fold-search' to `nil', then all
letters must match exactly, including case. This is a per-buffer
variable; altering the variable affects only the current buffer, but
there is a default value which you can change as well. *Note Locals::.
This variable applies to nonincremental searches also, including those
performed by the replace commands (*note Replace::.) and the minibuffer
history matching commands (*note Minibuffer History::.).
Replacement Commands
====================
Global search-and-replace operations are not needed as often in Emacs
as they are in other editors(1), but they are available. In addition
to the simple `M-x replace-string' command which is like that found in
most editors, there is a `M-x query-replace' command which asks you, for
each occurrence of the pattern, whether to replace it.
The replace commands normally operate on the text from point to the
end of the buffer; however, in Transient Mark mode, when the mark is
active, they operate on the region. The replace commands all replace
one string (or regexp) with one replacement string. It is possible to
perform several replacements in parallel using the command
`expand-region-abbrevs' (*note Expanding Abbrevs::.).
---------- Footnotes ----------
(1) In some editors, search-and-replace operations are the only
convenient way to make a single change in the text.
Unconditional Replacement
-------------------------
`M-x replace-string <RET> STRING <RET> NEWSTRING <RET>'
Replace every occurrence of STRING with NEWSTRING.
`M-x replace-regexp <RET> REGEXP <RET> NEWSTRING <RET>'
Replace every match for REGEXP with NEWSTRING.
To replace every instance of `foo' after point with `bar', use the
command `M-x replace-string' with the two arguments `foo' and `bar'.
Replacement happens only in the text after point, so if you want to
cover the whole buffer you must go to the beginning first. All
occurrences up to the end of the buffer are replaced; to limit
replacement to part of the buffer, narrow to that part of the buffer
before doing the replacement (*note Narrowing::.). In Transient Mark
mode, when the region is active, replacement is limited to the region
(*note Transient Mark::.).
When `replace-string' exits, it leaves point at the last occurrence
replaced. It sets the mark to the prior position of point (where the
`replace-string' command was issued); use `C-u C-<SPC>' to move back
there.
A numeric argument restricts replacement to matches that are
surrounded by word boundaries. The argument's value doesn't matter.
Regexp Replacement
------------------
The `M-x replace-string' command replaces exact matches for a single
string. The similar command `M-x replace-regexp' replaces any match
for a specified pattern.
In `replace-regexp', the NEWSTRING need not be constant: it can
refer to all or part of what is matched by the REGEXP. `\&' in
NEWSTRING stands for the entire match being replaced. `\D' in
NEWSTRING, where D is a digit, stands for whatever matched the Dth
parenthesized grouping in REGEXP. To include a `\' in the text to
replace with, you must enter `\\'. For example,
M-x replace-regexp <RET> c[ad]+r <RET> \&-safe <RET>
replaces (for example) `cadr' with `cadr-safe' and `cddr' with
`cddr-safe'.
M-x replace-regexp <RET> \(c[ad]+r\)-safe <RET> \1 <RET>
performs the inverse transformation.
Replace Commands and Case
-------------------------
If the first argument of a replace command is all lower case, the
commands ignores case while searching for occurrences to
replace--provided `case-fold-search' is non-`nil'. If
`case-fold-search' is set to `nil', case is always significant in all
searches.
In addition, when the NEWSTRING argument is all or partly lower
case, replacement commands try to preserve the case pattern of each
occurrence. Thus, the command
M-x replace-string <RET> foo <RET> bar <RET>
replaces a lower case `foo' with a lower case `bar', an all-caps `FOO'
with `BAR', and a capitalized `Foo' with `Bar'. (These three
alternatives--lower case, all caps, and capitalized, are the only ones
that `replace-string' can distinguish.)
If upper-case letters are used in the replacement string, they remain
upper case every time that text is inserted. If upper-case letters are
used in the first argument, the second argument is always substituted
exactly as given, with no case conversion. Likewise, if either
`case-replace' or `case-fold-search' is set to `nil', replacement is
done without case conversion.
Query Replace
-------------
`M-% STRING <RET> NEWSTRING <RET>'
`M-x query-replace <RET> STRING <RET> NEWSTRING <RET>'
Replace some occurrences of STRING with NEWSTRING.
`C-M-% REGEXP <RET> NEWSTRING <RET>'
`M-x query-replace-regexp <RET> REGEXP <RET> NEWSTRING <RET>'
Replace some matches for REGEXP with NEWSTRING.
If you want to change only some of the occurrences of `foo' to
`bar', not all of them, then you cannot use an ordinary
`replace-string'. Instead, use `M-%' (`query-replace'). This command
finds occurrences of `foo' one by one, displays each occurrence and
asks you whether to replace it. A numeric argument to `query-replace'
tells it to consider only occurrences that are bounded by
word-delimiter characters. This preserves case, just like
`replace-string', provided `case-replace' is non-`nil', as it normally
is.
Aside from querying, `query-replace' works just like
`replace-string', and `query-replace-regexp' works just like
`replace-regexp'. This command is run by `C-M-%'.
The things you can type when you are shown an occurrence of STRING
or a match for REGEXP are:
`<SPC>'
to replace the occurrence with NEWSTRING.
`<DEL>'
to skip to the next occurrence without replacing this one.
`, (Comma)'
to replace this occurrence and display the result. You are then
asked for another input character to say what to do next. Since
the replacement has already been made, <DEL> and <SPC> are
equivalent in this situation; both move to the next occurrence.
You can type `C-r' at this point (see below) to alter the replaced
text. You can also type `C-x u' to undo the replacement; this
exits the `query-replace', so if you want to do further
replacement you must use `C-x <ESC> <ESC> <RET>' to restart (*note
Repetition::.).
`<RET>'
to exit without doing any more replacements.
`. (Period)'
to replace this occurrence and then exit without searching for more
occurrences.
`!'
to replace all remaining occurrences without asking again.
`^'
to go back to the position of the previous occurrence (or what
used to be an occurrence), in case you changed it by mistake.
This works by popping the mark ring. Only one `^' in a row is
meaningful, because only one previous replacement position is kept
during `query-replace'.
`C-r'
to enter a recursive editing level, in case the occurrence needs
to be edited rather than just replaced with NEWSTRING. When you
are done, exit the recursive editing level with `C-M-c' to proceed
to the next occurrence. *Note Recursive Edit::.
`C-w'
to delete the occurrence, and then enter a recursive editing level
as in `C-r'. Use the recursive edit to insert text to replace the
deleted occurrence of STRING. When done, exit the recursive
editing level with `C-M-c' to proceed to the next occurrence.
`C-l'
to redisplay the screen. Then you must type another character to
specify what to do with this occurrence.
`C-h'
to display a message summarizing these options. Then you must type
another character to specify what to do with this occurrence.
Some other characters are aliases for the ones listed above: `y',
`n' and `q' are equivalent to <SPC>, <DEL> and <RET>.
Aside from this, any other character exits the `query-replace', and
is then reread as part of a key sequence. Thus, if you type `C-k', it
exits the `query-replace' and then kills to end of line.
To restart a `query-replace' once it is exited, use `C-x <ESC>
<ESC>', which repeats the `query-replace' because it used the
minibuffer to read its arguments. *Note C-x ESC ESC: Repetition.
See also *Note Transforming File Names::, for Dired commands to
rename, copy, or link files by replacing regexp matches in file names.
Other Search-and-Loop Commands
==============================
Here are some other commands that find matches for a regular
expression. They all operate from point to the end of the buffer, and
all ignore case in matching, if the pattern contains no upper-case
letters and `case-fold-search' is non-`nil'.
`M-x occur <RET> REGEXP <RET>'
Display a list showing each line in the buffer that contains a
match for REGEXP. A numeric argument specifies the number of
context lines to print before and after each matching line; the
default is none. To limit the search to part of the buffer,
narrow to that part (*note Narrowing::.).
The buffer `*Occur*' containing the output serves as a menu for
finding the occurrences in their original context. Click `Mouse-2'
on an occurrence listed in `*Occur*', or position point there and
type <RET>; this switches to the buffer that was searched and
moves point to the original of the chosen occurrence.
`M-x list-matching-lines'
Synonym for `M-x occur'.
`M-x count-matches <RET> REGEXP <RET>'
Print the number of matches for REGEXP after point.
`M-x flush-lines <RET> REGEXP <RET>'
Delete each line that follows point and contains a match for
REGEXP.
`M-x keep-lines <RET> REGEXP <RET>'
Delete each line that follows point and *does not* contain a match
for REGEXP.
In addition, you can use `grep' from Emacs to search a collection of
files for matches for a regular expression, then visit the matches
either sequentially or in arbitrary order. *Note Grep Searching::.
Commands for Fixing Typos
*************************
In this chapter we describe the commands that are especially useful
for the times when you catch a mistake in your text just after you have
made it, or change your mind while composing text on the fly.
The most fundamental command for correcting erroneous editing is the
undo command, `C-x u' or `C-_'. This command undoes a single command
(usually), a part of a command (in the case of `query-replace'), or
several consecutive self-inserting characters. Consecutive repetitions
of `C-_' or `C-x u' undo earlier and earlier changes, back to the limit
of the undo information available. *Note Undo::, for for more
information.
Killing Your Mistakes
=====================
`<DEL>'
Delete last character (`delete-backward-char').
`M-<DEL>'
Kill last word (`backward-kill-word').
`C-x <DEL>'
Kill to beginning of sentence (`backward-kill-sentence').
The <DEL> character (`delete-backward-char') is the most important
correction command. It deletes the character before point. When <DEL>
follows a self-inserting character command, you can think of it as
canceling that command. However, avoid the mistake of thinking of
<DEL> as a general way to cancel a command!
When your mistake is longer than a couple of characters, it might be
more convenient to use `M-<DEL>' or `C-x <DEL>'. `M-<DEL>' kills back
to the start of the last word, and `C-x <DEL>' kills back to the start
of the last sentence. `C-x <DEL>' is particularly useful when you
change your mind about the phrasing of the text you are writing.
`M-<DEL>' and `C-x <DEL>' save the killed text for `C-y' and `M-y' to
retrieve. *Note Yanking::.
`M-<DEL>' is often useful even when you have typed only a few
characters wrong, if you know you are confused in your typing and aren't
sure exactly what you typed. At such a time, you cannot correct with
<DEL> except by looking at the screen to see what you did. Often it
requires less thought to kill the whole word and start again.
Transposing Text
================
`C-t'
Transpose two characters (`transpose-chars').
`M-t'
Transpose two words (`transpose-words').
`C-M-t'
Transpose two balanced expressions (`transpose-sexps').
`C-x C-t'
Transpose two lines (`transpose-lines').
The common error of transposing two characters can be fixed, when
they are adjacent, with the `C-t' command (`transpose-chars').
Normally, `C-t' transposes the two characters on either side of point.
When given at the end of a line, rather than transposing the last
character of the line with the newline, which would be useless, `C-t'
transposes the last two characters on the line. So, if you catch your
transposition error right away, you can fix it with just a `C-t'. If
you don't catch it so fast, you must move the cursor back to between
the two transposed characters. If you transposed a space with the last
character of the word before it, the word motion commands are a good
way of getting there. Otherwise, a reverse search (`C-r') is often the
best way. *Note Search::.
`M-t' (`transpose-words') transposes the word before point with the
word after point. It moves point forward over a word, dragging the
word preceding or containing point forward as well. The punctuation
characters between the words do not move. For example, `FOO, BAR'
transposes into `BAR, FOO' rather than `BAR FOO,'.
`C-M-t' (`transpose-sexps') is a similar command for transposing two
expressions (*note Lists::.), and `C-x C-t' (`transpose-lines')
exchanges lines. They work like `M-t' except in determining the
division of the text into syntactic units.
A numeric argument to a transpose command serves as a repeat count:
it tells the transpose command to move the character (word, sexp, line)
before or containing point across several other characters (words,
sexps, lines). For example, `C-u 3 C-t' moves the character before
point forward across three other characters. It would change
`f-!-oobar' into `oobf-!-ar'. This is equivalent to repeating `C-t'
three times. `C-u - 4 M-t' moves the word before point backward across
four words. `C-u - C-M-t' would cancel the effect of plain `C-M-t'.
A numeric argument of zero is assigned a special meaning (because
otherwise a command with a repeat count of zero would do nothing): to
transpose the character (word, sexp, line) ending after point with the
one ending after the mark.
Case Conversion
===============
`M-- M-l'
Convert last word to lower case. Note `Meta--' is Meta-minus.
`M-- M-u'
Convert last word to all upper case.
`M-- M-c'
Convert last word to lower case with capital initial.
A very common error is to type words in the wrong case. Because of
this, the word case-conversion commands `M-l', `M-u' and `M-c' have a
special feature when used with a negative argument: they do not move the
cursor. As soon as you see you have mistyped the last word, you can
simply case-convert it and go on typing. *Note Case::.
Checking and Correcting Spelling
================================
This section describes the commands to check the spelling of a single
word or of a portion of a buffer. These commands work with the spelling
checker program Ispell, which is not part of Emacs. *Note Ispell:
(ispell.info)Top.
`M-x flyspell-mode'
Enable Flyspell mode, which highlights all misspelled words.
`M-$'
Check and correct spelling of the word at point (`ispell-word').
`M-<TAB>'
Complete the word before point based on the spelling dictionary
(`ispell-complete-word').
`M-x ispell-buffer'
Check and correct spelling of each word in the buffer.
`M-x ispell-region'
Check and correct spelling of each word in the region.
`M-x ispell-message'
Check and correct spelling of each word in a draft mail message,
excluding cited material.
`M-x ispell-change-dictionary <RET> DICT <RET>'
Restart the Ispell process, using DICT as the dictionary.
`M-x ispell-kill-ispell'
Kill the Ispell subprocess.
Flyspell mode is a fully-automatic way to check spelling as you edit
in Emacs. It operates by checking words as you change or insert them.
When it finds a word that it does not recognize, it highlights that
word. This does not interfere with your editing, but when you see the
highlighted word, you can move to it and fix it. Type `M-x
flyspell-mode' to enable or disable this mode in the current buffer.
When Flyspell mode highlights a word as misspelled, you can click on
it with `Mouse-2' to display a menu of possible corrections and
actions. You can also correct the word by editing it manually in any
way you like.
The other Emacs spell-checking features check or look up words when
you give an explicit command to do so. Checking all or part of the
buffer is useful when you have text that was written outside of this
Emacs session and might contain any number of misspellings.
To check the spelling of the word around or next to point, and
optionally correct it as well, use the command `M-$' (`ispell-word').
If the word is not correct, the command offers you various alternatives
for what to do about it.
To check the entire current buffer, use `M-x ispell-buffer'. Use
`M-x ispell-region' to check just the current region. To check
spelling in an email message you are writing, use `M-x ispell-message';
that checks the whole buffer, but does not check material that is
indented or appears to be cited from other messages.
Each time these commands encounter an incorrect word, they ask you
what to do. They display a list of alternatives, usually including
several "near-misses"--words that are close to the word being checked.
Then you must type a character. Here are the valid responses:
`<SPC>'
Skip this word--continue to consider it incorrect, but don't
change it here.
`r NEW <RET>'
Replace the word (just this time) with NEW.
`R NEW <RET>'
Replace the word with NEW, and do a `query-replace' so you can
replace it elsewhere in the buffer if you wish.
`DIGIT'
Replace the word (just this time) with one of the displayed
near-misses. Each near-miss is listed with a digit; type that
digit to select it.
`a'
Accept the incorrect word--treat it as correct, but only in this
editing session.
`A'
Accept the incorrect word--treat it as correct, but only in this
editing session and for this buffer.
`i'
Insert this word in your private dictionary file so that Ispell
will consider it correct it from now on, even in future sessions.
`u'
Insert the lower-case version of this word in your private
dictionary file.
`m'
Like `i', but you can also specify dictionary completion
information.
`l WORD <RET>'
Look in the dictionary for words that match WORD. These words
become the new list of "near-misses"; you can select one of them to
replace with by typing a digit. You can use `*' in WORD as a
wildcard.
`C-g'
Quit interactive spell checking. You can restart it again
afterward with `C-u M-$'.
`X'
Same as `C-g'.
`x'
Quit interactive spell checking and move point back to where it was
when you started spell checking.
`q'
Quit interactive spell checking and kill the Ispell subprocess.
`C-l'
Refresh the screen.
`C-z'
This key has its normal command meaning (suspend Emacs or iconify
this frame).
The command `ispell-complete-word', which is bound to the key
`M-<TAB>' in Text mode and related modes, shows a list of completions
based on spelling correction. Insert the beginning of a word, and then
type `M-<TAB>'; the command displays a completion list window. To
choose one of the completions listed, click `Mouse-2' on it, or move
the cursor there in the completions window and type <RET>. *Note Text
Mode::.
Once started, the Ispell subprocess continues to run (waiting for
something to do), so that subsequent spell checking commands complete
more quickly. If you want to get rid of the Ispell process, use `M-x
ispell-kill-ispell'. This is not usually necessary, since the process
uses no time except when you do spelling correction.
Ispell uses two dictionaries: the standard dictionary and your
private dictionary. The variable `ispell-dictionary' specifies the file
name of the standard dictionary to use. A value of `nil' says to use
the default dictionary. The command `M-x ispell-change-dictionary'
sets this variable and then restarts the Ispell subprocess, so that it
will use a different dictionary.
File Handling
*************
The operating system stores data permanently in named "files". So
most of the text you edit with Emacs comes from a file and is ultimately
stored in a file.
To edit a file, you must tell Emacs to read the file and prepare a
buffer containing a copy of the file's text. This is called "visiting"
the file. Editing commands apply directly to text in the buffer; that
is, to the copy inside Emacs. Your changes appear in the file itself
only when you "save" the buffer back into the file.
In addition to visiting and saving files, Emacs can delete, copy,
rename, and append to files, keep multiple versions of them, and operate
on file directories.
File Names
==========
Most Emacs commands that operate on a file require you to specify the
file name. (Saving and reverting are exceptions; the buffer knows which
file name to use for them.) You enter the file name using the
minibuffer (*note Minibuffer::.). "Completion" is available, to make
it easier to specify long file names. *Note Completion::.
For most operations, there is a "default file name" which is used if
you type just <RET> to enter an empty argument. Normally the default
file name is the name of the file visited in the current buffer; this
makes it easy to operate on that file with any of the Emacs file
commands.
Each buffer has a default directory, normally the same as the
directory of the file visited in that buffer. When you enter a file
name without a directory, the default directory is used. If you specify
a directory in a relative fashion, with a name that does not start with
a slash, it is interpreted with respect to the default directory. The
default directory is kept in the variable `default-directory', which
has a separate value in every buffer.
For example, if the default file name is `/u/rms/gnu/gnu.tasks' then
the default directory is `/u/rms/gnu/'. If you type just `foo', which
does not specify a directory, it is short for `/u/rms/gnu/foo'.
`../.login' would stand for `/u/rms/.login'. `new/foo' would stand for
the file name `/u/rms/gnu/new/foo'.
The command `M-x pwd' prints the current buffer's default directory,
and the command `M-x cd' sets it (to a value read using the
minibuffer). A buffer's default directory changes only when the `cd'
command is used. A file-visiting buffer's default directory is
initialized to the directory of the file that is visited there. If you
create a buffer with `C-x b', its default directory is copied from that
of the buffer that was current at the time.
The default directory actually appears in the minibuffer when the
minibuffer becomes active to read a file name. This serves two
purposes: it *shows* you what the default is, so that you can type a
relative file name and know with certainty what it will mean, and it
allows you to *edit* the default to specify a different directory.
This insertion of the default directory is inhibited if the variable
`insert-default-directory' is set to `nil'.
Note that it is legitimate to type an absolute file name after you
enter the minibuffer, ignoring the presence of the default directory
name as part of the text. The final minibuffer contents may look
invalid, but that is not so. For example, if the minibuffer starts out
with `/usr/tmp/' and you add `/x1/rms/foo', you get
`/usr/tmp//x1/rms/foo'; but Emacs ignores everything through the first
slash in the double slash; the result is `/x1/rms/foo'. *Note
Minibuffer File::.
`$' in a file name is used to substitute environment variables. For
example, if you have used the shell command `export FOO=rms/hacks' to
set up an environment variable named `FOO', then you can use
`/u/$FOO/test.c' or `/u/${FOO}/test.c' as an abbreviation for
`/u/rms/hacks/test.c'. The environment variable name consists of all
the alphanumeric characters after the `$'; alternatively, it may be
enclosed in braces after the `$'. Note that shell commands to set
environment variables affect Emacs only if done before Emacs is started.
To access a file with `$' in its name, type `$$'. This pair is
converted to a single `$' at the same time as variable substitution is
performed for single `$'. Alternatively, quote the whole file name
with `/:' (*note Quoted File Names::.).
The Lisp function that performs the substitution is called
`substitute-in-file-name'. The substitution is performed only on file
names read as such using the minibuffer.
You can include non-ASCII characters in file names if you set the
variable `file-name-coding-system' to a non-`nil' value. *Note Specify
Coding::.
Visiting Files
==============
`C-x C-f'
Visit a file (`find-file').
`C-x C-r'
Visit a file for viewing, without allowing changes to it
(`find-file-read-only').
`C-x C-v'
Visit a different file instead of the one visited last
(`find-alternate-file').
`C-x 4 f'
Visit a file, in another window (`find-file-other-window'). Don't
alter what is displayed in the selected window.
`C-x 5 f'
Visit a file, in a new frame (`find-file-other-frame'). Don't
alter what is displayed in the selected frame.
`M-x find-file-literally'
Visit a file with no conversion of the contents.
"Visiting" a file means copying its contents into an Emacs buffer so
you can edit them. Emacs makes a new buffer for each file that you
visit. We say that this buffer is visiting the file that it was created
to hold. Emacs constructs the buffer name from the file name by
throwing away the directory, keeping just the name proper. For example,
a file named `/usr/rms/emacs.tex' would get a buffer named `emacs.tex'.
If there is already a buffer with that name, a unique name is
constructed by appending `<2>', `<3>', or so on, using the lowest
number that makes a name that is not already in use.
Each window's mode line shows the name of the buffer that is being
displayed in that window, so you can always tell what buffer you are
editing.
The changes you make with editing commands are made in the Emacs
buffer. They do not take effect in the file that you visited, or any
place permanent, until you "save" the buffer. Saving the buffer means
that Emacs writes the current contents of the buffer into its visited
file. *Note Saving::.
If a buffer contains changes that have not been saved, we say the
buffer is "modified". This is important because it implies that some
changes will be lost if the buffer is not saved. The mode line
displays two stars near the left margin to indicate that the buffer is
modified.
To visit a file, use the command `C-x C-f' (`find-file'). Follow
the command with the name of the file you wish to visit, terminated by a
<RET>.
The file name is read using the minibuffer (*note Minibuffer::.),
with defaulting and completion in the standard manner (*note File
Names::.). While in the minibuffer, you can abort `C-x C-f' by typing
`C-g'.
Your confirmation that `C-x C-f' has completed successfully is the
appearance of new text on the screen and a new buffer name in the mode
line. If the specified file does not exist and could not be created, or
cannot be read, then you get an error, with an error message displayed
in the echo area.
If you visit a file that is already in Emacs, `C-x C-f' does not make
another copy. It selects the existing buffer containing that file.
However, before doing so, it checks that the file itself has not changed
since you visited or saved it last. If the file has changed, a warning
message is printed. *Note Simultaneous Editing: Interlocking.
What if you want to create a new file? Just visit it. Emacs prints
`(New File)' in the echo area, but in other respects behaves as if you
had visited an existing empty file. If you make any changes and save
them, the file is created.
Emacs recognizes from the contents of a file which convention it uses
to separate lines--newline (used on GNU/Linux and on Unix),
carriage-return linefeed (used on Microsoft systems), or just
carriage-return (used on the Macintosh)--and automatically converts the
contents to the normal Emacs convention, which is that the newline
character separates lines. This is a part of the general feature of
coding system conversion (*note Coding Systems::.), and makes it
possible to edit files imported from various different operating
systems with equal convenience. If you change the text and save the
file, Emacs performs the inverse conversion, changing newlines back into
carriage-return linefeed or just carriage-return if appropriate.
If the file you specify is actually a directory, `C-x C-f' invokes
Dired, the Emacs directory browser, so that you can "edit" the contents
of the directory (*note Dired::.). Dired is a convenient way to delete,
look at, or operate on the files in the directory. However, if the
variable `find-file-run-dired' is `nil', then it is an error to try to
visit a directory.
If the file name you specify contains wildcard characters, Emacs
visits all the files that match it. *Note Quoted File Names::, if you
want to visit a file whose name actually contains wildcard characters.
If you visit a file that the operating system won't let you modify,
Emacs makes the buffer read-only, so that you won't go ahead and make
changes that you'll have trouble saving afterward. You can make the
buffer writable with `C-x C-q' (`vc-toggle-read-only'). *Note Misc
Buffer::.
Occasionally you might want to visit a file as read-only in order to
protect yourself from entering changes accidentally; do so by visiting
the file with the command `C-x C-r' (`find-file-read-only').
If you visit a nonexistent file unintentionally (because you typed
the wrong file name), use the `C-x C-v' command (`find-alternate-file')
to visit the file you really wanted. `C-x C-v' is similar to `C-x
C-f', but it kills the current buffer (after first offering to save it
if it is modified). When it reads the file name to visit, it inserts
the entire default file name in the buffer, with point just after the
directory part; this is convenient if you made a slight error in typing
the name.
If you find a file which exists but cannot be read, `C-x C-f'
signals an error.
`C-x 4 f' (`find-file-other-window') is like `C-x C-f' except that
the buffer containing the specified file is selected in another window.
The window that was selected before `C-x 4 f' continues to show the
same buffer it was already showing. If this command is used when only
one window is being displayed, that window is split in two, with one
window showing the same buffer as before, and the other one showing the
newly requested file. *Note Windows::.
`C-x 5 f' (`find-file-other-frame') is similar, but opens a new
frame, or makes visible any existing frame showing the file you seek.
This feature is available only when you are using a window system.
*Note Frames::.
If you wish to edit a file as a sequence of characters with no
special encoding or conversion, use the `M-x find-file-literally'
command. It visits a file, like `C-x C-f', but does not do format
conversion (*note Formatted Text::.), character code conversion (*note
Coding Systems::.), or automatic uncompression (*note Compressed
Files::.). If you already have visited the same file in the usual
(non-literal) manner, this command asks you whether to visit it
literally instead.
Two special hook variables allow extensions to modify the operation
of visiting files. Visiting a file that does not exist runs the
functions in the list `find-file-not-found-hooks'; this variable holds
a list of functions, and the functions are called one by one until one
of them returns non-`nil'. Any visiting of a file, whether extant or
not, expects `find-file-hooks' to contain a list of functions and calls
them all, one by one. In both cases the functions receive no
arguments. Of these two variables, `find-file-not-found-hooks' takes
effect first. These variables are *not* normal hooks, and their names
end in `-hooks' rather than `-hook' to indicate that fact. *Note
Hooks::.
There are several ways to specify automatically the major mode for
editing the file (*note Choosing Modes::.), and to specify local
variables defined for that file (*note File Variables::.).
Saving Files
============
"Saving" a buffer in Emacs means writing its contents back into the
file that was visited in the buffer.
`C-x C-s'
Save the current buffer in its visited file (`save-buffer').
`C-x s'
Save any or all buffers in their visited files
(`save-some-buffers').
`M-~'
Forget that the current buffer has been changed (`not-modified').
`C-x C-w'
Save the current buffer in a specified file (`write-file').
`M-x set-visited-file-name'
Change file the name under which the current buffer will be saved.
When you wish to save the file and make your changes permanent, type
`C-x C-s' (`save-buffer'). After saving is finished, `C-x C-s'
displays a message like this:
Wrote /u/rms/gnu/gnu.tasks
If the selected buffer is not modified (no changes have been made in it
since the buffer was created or last saved), saving is not really done,
because it would have no effect. Instead, `C-x C-s' displays a message
like this in the echo area:
(No changes need to be saved)
The command `C-x s' (`save-some-buffers') offers to save any or all
modified buffers. It asks you what to do with each buffer. The
possible responses are analogous to those of `query-replace':
`y'
Save this buffer and ask about the rest of the buffers.
`n'
Don't save this buffer, but ask about the rest of the buffers.
`!'
Save this buffer and all the rest with no more questions.
`<RET>'
Terminate `save-some-buffers' without any more saving.
`.'
Save this buffer, then exit `save-some-buffers' without even asking
about other buffers.
`C-r'
View the buffer that you are currently being asked about. When
you exit View mode, you get back to `save-some-buffers', which
asks the question again.
`C-h'
Display a help message about these options.
`C-x C-c', the key sequence to exit Emacs, invokes
`save-some-buffers' and therefore asks the same questions.
If you have changed a buffer but you do not want to save the changes,
you should take some action to prevent it. Otherwise, each time you use
`C-x s' or `C-x C-c', you are liable to save this buffer by mistake.
One thing you can do is type `M-~' (`not-modified'), which clears out
the indication that the buffer is modified. If you do this, none of
the save commands will believe that the buffer needs to be saved. (`~'
is often used as a mathematical symbol for `not'; thus `M-~' is `not',
metafied.) You could also use `set-visited-file-name' (see below) to
mark the buffer as visiting a different file name, one which is not in
use for anything important. Alternatively, you can cancel all the
changes made since the file was visited or saved, by reading the text
from the file again. This is called "reverting". *Note Reverting::.
You could also undo all the changes by repeating the undo command `C-x
u' until you have undone all the changes; but reverting is easier.
`M-x set-visited-file-name' alters the name of the file that the
current buffer is visiting. It reads the new file name using the
minibuffer. Then it specifies the visited file name and changes the
buffer name correspondingly (as long as the new name is not in use).
`set-visited-file-name' does not save the buffer in the newly visited
file; it just alters the records inside Emacs in case you do save
later. It also marks the buffer as "modified" so that `C-x C-s' in
that buffer *will* save.
If you wish to mark the buffer as visiting a different file and save
it right away, use `C-x C-w' (`write-file'). It is precisely
equivalent to `set-visited-file-name' followed by `C-x C-s'. `C-x C-s'
used on a buffer that is not visiting a file has the same effect as
`C-x C-w'; that is, it reads a file name, marks the buffer as visiting
that file, and saves it there. The default file name in a buffer that
is not visiting a file is made by combining the buffer name with the
buffer's default directory.
If the new file name implies a major mode, then `C-x C-w' switches
to that major mode, in most cases. The command `set-visited-file-name'
also does this. *Note Choosing Modes::.
If Emacs is about to save a file and sees that the date of the latest
version on disk does not match what Emacs last read or wrote, Emacs
notifies you of this fact, because it probably indicates a problem
caused by simultaneous editing and requires your immediate attention.
*Note Simultaneous Editing: Interlocking.
If the variable `require-final-newline' is non-`nil', Emacs puts a
newline at the end of any file that doesn't already end in one, every
time a file is saved or written. The default is `nil'.
Backup Files
------------
On most operating systems, rewriting a file automatically destroys
all record of what the file used to contain. Thus, saving a file from
Emacs throws away the old contents of the file--or it would, except that
Emacs carefully copies the old contents to another file, called the
"backup" file, before actually saving.
For most files, the variable `make-backup-files' determines whether
to make backup files. On most operating systems, its default value is
`t', so that Emacs does write backup files.
For files managed by a version control system (*note Version
Control::.), the variable `vc-make-backup-files' determines whether to
make backup files. By default, it is `nil', since backup files are
redundant when you store all the previous versions in a version control
system. *Note VC Workfile Handling::.
The default value of the `backup-enable-predicate' variable prevents
backup files being written for files in `/tmp'.
At your option, Emacs can keep either a single backup file or a
series of numbered backup files for each file that you edit.
Emacs makes a backup for a file only the first time the file is saved
from one buffer. No matter how many times you save a file, its backup
file continues to contain the contents from before the file was visited.
Normally this means that the backup file contains the contents from
before the current editing session; however, if you kill the buffer and
then visit the file again, a new backup file will be made by the next
save.
You can also explicitly request making another backup file from a
buffer even though it has already been saved at least once. If you save
the buffer with `C-u C-x C-s', the version thus saved will be made into
a backup file if you save the buffer again. `C-u C-u C-x C-s' saves
the buffer, but first makes the previous file contents into a new
backup file. `C-u C-u C-u C-x C-s' does both things: it makes a backup
from the previous contents, and arranges to make another from the newly
saved contents, if you save again.
Single or Numbered Backups
..........................
If you choose to have a single backup file (this is the default),
the backup file's name is constructed by appending `~' to the file name
being edited; thus, the backup file for `eval.c' would be `eval.c~'.
If you choose to have a series of numbered backup files, backup file
names are made by appending `.~', the number, and another `~' to the
original file name. Thus, the backup files of `eval.c' would be called
`eval.c.~1~', `eval.c.~2~', and so on, through names like
`eval.c.~259~' and beyond.
If protection stops you from writing backup files under the usual
names, the backup file is written as `%backup%~' in your home directory.
Only one such file can exist, so only the most recently made such
backup is available.
The choice of single backup or numbered backups is controlled by the
variable `version-control'. Its possible values are
`t'
Make numbered backups.
`nil'
Make numbered backups for files that have numbered backups already.
Otherwise, make single backups.
`never'
Do not in any case make numbered backups; always make single
backups.
You can set `version-control' locally in an individual buffer to
control the making of backups for that buffer's file. For example,
Rmail mode locally sets `version-control' to `never' to make sure that
there is only one backup for an Rmail file. *Note Locals::.
If you set the environment variable `VERSION_CONTROL', to tell
various GNU utilities what to do with backup files, Emacs also obeys the
environment variable by setting the Lisp variable `version-control'
accordingly at startup. If the environment variable's value is `t' or
`numbered', then `version-control' becomes `t'; if the value is `nil'
or `existing', then `version-control' becomes `nil'; if it is `never'
or `simple', then `version-control' becomes `never'.
Automatic Deletion of Backups
.............................
To prevent unlimited consumption of disk space, Emacs can delete
numbered backup versions automatically. Generally Emacs keeps the
first few backups and the latest few backups, deleting any in between.
This happens every time a new backup is made.
The two variables `kept-old-versions' and `kept-new-versions'
control this deletion. Their values are, respectively the number of
oldest (lowest-numbered) backups to keep and the number of newest
(highest-numbered) ones to keep, each time a new backup is made.
Recall that these values are used just after a new backup version is
made; that newly made backup is included in the count in
`kept-new-versions'. By default, both variables are 2.
If `delete-old-versions' is non-`nil', the excess middle versions
are deleted without a murmur. If it is `nil', the default, then you
are asked whether the excess middle versions should really be deleted.
Dired's `.' (Period) command can also be used to delete old versions.
*Note Dired Deletion::.
Copying vs. Renaming
....................
Backup files can be made by copying the old file or by renaming it.
This makes a difference when the old file has multiple names. If the
old file is renamed into the backup file, then the alternate names
become names for the backup file. If the old file is copied instead,
then the alternate names remain names for the file that you are
editing, and the contents accessed by those names will be the new
contents.
The method of making a backup file may also affect the file's owner
and group. If copying is used, these do not change. If renaming is
used, you become the file's owner, and the file's group becomes the
default (different operating systems have different defaults for the
group).
Having the owner change is usually a good idea, because then the
owner always shows who last edited the file. Also, the owners of the
backups show who produced those versions. Occasionally there is a file
whose owner should not change; it is a good idea for such files to
contain local variable lists to set `backup-by-copying-when-mismatch'
locally (*note File Variables::.).
The choice of renaming or copying is controlled by three variables.
Renaming is the default choice. If the variable `backup-by-copying' is
non-`nil', copying is used. Otherwise, if the variable
`backup-by-copying-when-linked' is non-`nil', then copying is used for
files that have multiple names, but renaming may still be used when the
file being edited has only one name. If the variable
`backup-by-copying-when-mismatch' is non-`nil', then copying is used if
renaming would cause the file's owner or group to change.
`backup-by-copying-when-mismatch' is `t' by default if you start Emacs
as the superuser.
When a file is managed with a version control system (*note Version
Control::.), Emacs does not normally make backups in the usual way for
that file. But check-in and check-out are similar in some ways to
making backups. One unfortunate similarity is that these operations
typically break hard links, disconnecting the file name you visited from
any alternate names for the same file. This has nothing to do with
Emacs--the version control system does it.
Protection against Simultaneous Editing
---------------------------------------
Simultaneous editing occurs when two users visit the same file, both
make changes, and then both save them. If nobody were informed that
this was happening, whichever user saved first would later find that his
changes were lost.
On some systems, Emacs notices immediately when the second user
starts to change the file, and issues an immediate warning. On all
systems, Emacs checks when you save the file, and warns if you are
about to overwrite another user's changes. You can prevent loss of the
other user's work by taking the proper corrective action instead of
saving the file.
When you make the first modification in an Emacs buffer that is
visiting a file, Emacs records that the file is "locked" by you. (It
does this by creating a symbolic link in the same directory with a
different name.) Emacs removes the lock when you save the changes. The
idea is that the file is locked whenever an Emacs buffer visiting it has
unsaved changes.
If you begin to modify the buffer while the visited file is locked by
someone else, this constitutes a "collision". When Emacs detects a
collision, it asks you what to do, by calling the Lisp function
`ask-user-about-lock'. You can redefine this function for the sake of
customization. The standard definition of this function asks you a
question and accepts three possible answers:
`s'
Steal the lock. Whoever was already changing the file loses the
lock, and you gain the lock.
`p'
Proceed. Go ahead and edit the file despite its being locked by
someone else.
`q'
Quit. This causes an error (`file-locked') and the modification
you were trying to make in the buffer does not actually take place.
Note that locking works on the basis of a file name; if a file has
multiple names, Emacs does not realize that the two names are the same
file and cannot prevent two users from editing it simultaneously under
different names. However, basing locking on names means that Emacs can
interlock the editing of new files that will not really exist until
they are saved.
Some systems are not configured to allow Emacs to make locks, and
there are cases where lock files cannot be written. In these cases,
Emacs cannot detect trouble in advance, but it still can detect the
collision when you try to save a file and overwrite someone else's
changes.
If Emacs or the operating system crashes, this may leave behind lock
files which are stale. So you may occasionally get warnings about
spurious collisions. When you determine that the collision is spurious,
just use `p' to tell Emacs to go ahead anyway.
Every time Emacs saves a buffer, it first checks the
last-modification date of the existing file on disk to verify that it
has not changed since the file was last visited or saved. If the date
does not match, it implies that changes were made in the file in some
other way, and these changes are about to be lost if Emacs actually
does save. To prevent this, Emacs prints a warning message and asks
for confirmation before saving. Occasionally you will know why the
file was changed and know that it does not matter; then you can answer
`yes' and proceed. Otherwise, you should cancel the save with `C-g'
and investigate the situation.
The first thing you should do when notified that simultaneous editing
has already taken place is to list the directory with `C-u C-x C-d'
(*note Directories::.). This shows the file's current author. You
should attempt to contact him to warn him not to continue editing.
Often the next step is to save the contents of your Emacs buffer under a
different name, and use `diff' to compare the two files.
Reverting a Buffer
==================
If you have made extensive changes to a file and then change your
mind about them, you can get rid of them by reading in the previous
version of the file. To do this, use `M-x revert-buffer', which
operates on the current buffer. Since reverting a buffer
unintentionally could lose a lot of work, you must confirm this command
with `yes'.
`revert-buffer' keeps point at the same distance (measured in
characters) from the beginning of the file. If the file was edited only
slightly, you will be at approximately the same piece of text after
reverting as before. If you have made drastic changes, the same value
of point in the old file may address a totally different piece of text.
Reverting marks the buffer as "not modified" until another change is
made.
Some kinds of buffers whose contents reflect data bases other than
files, such as Dired buffers, can also be reverted. For them,
reverting means recalculating their contents from the appropriate data
base. Buffers created explicitly with `C-x b' cannot be reverted;
`revert-buffer' reports an error when asked to do so.
When you edit a file that changes automatically and frequently--for
example, a log of output from a process that continues to run--it may be
useful for Emacs to revert the file without querying you, whenever you
visit the file again with `C-x C-f'.
To request this behavior, set the variable `revert-without-query' to
a list of regular expressions. When a file name matches one of these
regular expressions, `find-file' and `revert-buffer' will revert it
automatically if it has changed--provided the buffer itself is not
modified. (If you have edited the text, it would be wrong to discard
your changes.)
Auto-Saving: Protection Against Disasters
=========================================
Emacs saves all the visited files from time to time (based on
counting your keystrokes) without being asked. This is called
"auto-saving". It prevents you from losing more than a limited amount
of work if the system crashes.
When Emacs determines that it is time for auto-saving, each buffer is
considered, and is auto-saved if auto-saving is turned on for it and it
has been changed since the last time it was auto-saved. The message
`Auto-saving...' is displayed in the echo area during auto-saving, if
any files are actually auto-saved. Errors occurring during auto-saving
are caught so that they do not interfere with the execution of commands
you have been typing.
Auto-Save Files
---------------
Auto-saving does not normally save in the files that you visited,
because it can be very undesirable to save a program that is in an
inconsistent state when you have made half of a planned change.
Instead, auto-saving is done in a different file called the "auto-save
file", and the visited file is changed only when you request saving
explicitly (such as with `C-x C-s').
Normally, the auto-save file name is made by appending `#' to the
front and rear of the visited file name. Thus, a buffer visiting file
`foo.c' is auto-saved in a file `#foo.c#'. Most buffers that are not
visiting files are auto-saved only if you request it explicitly; when
they are auto-saved, the auto-save file name is made by appending `#%'
to the front and `#' to the rear of buffer name. For example, the
`*mail*' buffer in which you compose messages to be sent is auto-saved
in a file named `#%*mail*#'. Auto-save file names are made this way
unless you reprogram parts of Emacs to do something different (the
functions `make-auto-save-file-name' and `auto-save-file-name-p'). The
file name to be used for auto-saving in a buffer is calculated when
auto-saving is turned on in that buffer.
When you delete a substantial part of the text in a large buffer,
auto save turns off temporarily in that buffer. This is because if you
deleted the text unintentionally, you might find the auto-save file more
useful if it contains the deleted text. To reenable auto-saving after
this happens, save the buffer with `C-x C-s', or use `C-u 1 M-x
auto-save'.
If you want auto-saving to be done in the visited file, set the
variable `auto-save-visited-file-name' to be non-`nil'. In this mode,
there is really no difference between auto-saving and explicit saving.
A buffer's auto-save file is deleted when you save the buffer in its
visited file. To inhibit this, set the variable
`delete-auto-save-files' to `nil'. Changing the visited file name with
`C-x C-w' or `set-visited-file-name' renames any auto-save file to go
with the new visited name.
Controlling Auto-Saving
-----------------------
Each time you visit a file, auto-saving is turned on for that file's
buffer if the variable `auto-save-default' is non-`nil' (but not in
batch mode; *note Entering Emacs::.). The default for this variable is
`t', so auto-saving is the usual practice for file-visiting buffers.
Auto-saving can be turned on or off for any existing buffer with the
command `M-x auto-save-mode'. Like other minor mode commands, `M-x
auto-save-mode' turns auto-saving on with a positive argument, off with
a zero or negative argument; with no argument, it toggles.
Emacs does auto-saving periodically based on counting how many
characters you have typed since the last time auto-saving was done.
The variable `auto-save-interval' specifies how many characters there
are between auto-saves. By default, it is 300.
Auto-saving also takes place when you stop typing for a while. The
variable `auto-save-timeout' says how many seconds Emacs should wait
before it does an auto save (and perhaps also a garbage collection).
(The actual time period is longer if the current buffer is long; this
is a heuristic which aims to keep out of your way when you are editing
long buffers, in which auto-save takes an appreciable amount of time.)
Auto-saving during idle periods accomplishes two things: first, it
makes sure all your work is saved if you go away from the terminal for
a while; second, it may avoid some auto-saving while you are actually
typing.
Emacs also does auto-saving whenever it gets a fatal error. This
includes killing the Emacs job with a shell command such as `kill
%emacs', or disconnecting a phone line or network connection.
You can request an auto-save explicitly with the command `M-x
do-auto-save'.
Recovering Data from Auto-Saves
-------------------------------
You can use the contents of an auto-save file to recover from a loss
of data with the command `M-x recover-file <RET> FILE <RET>'. This
visits FILE and then (after your confirmation) restores the contents
from its auto-save file `#FILE#'. You can then save with `C-x C-s' to
put the recovered text into FILE itself. For example, to recover file
`foo.c' from its auto-save file `#foo.c#', do:
M-x recover-file <RET> foo.c <RET>
yes <RET>
C-x C-s
Before asking for confirmation, `M-x recover-file' displays a
directory listing describing the specified file and the auto-save file,
so you can compare their sizes and dates. If the auto-save file is
older, `M-x recover-file' does not offer to read it.
If Emacs or the computer crashes, you can recover all the files you
were editing from their auto save files with the command `M-x
recover-session'. This first shows you a list of recorded interrupted
sessions. Move point to the one you choose, and type `C-c C-c'.
Then `recover-session' asks about each of the files that were being
edited during that session, asking whether to recover that file. If
you answer `y', it calls `recover-file', which works in its normal
fashion. It shows the dates of the original file and its auto-save
file, and asks once again whether to recover that file.
When `recover-session' is done, the files you've chosen to recover
are present in Emacs buffers. You should then save them. Only
this--saving them--updates the files themselves.
Interrupted sessions are recorded for later recovery in files named
`~/.saves-PID-HOSTNAME'. The `~/.saves' portion of these names comes
from the value of `auto-save-list-file-prefix'. You can arrange to
record sessions in a different place by setting that variable in your
`.emacs' file, but you'll have to redefine `recover-session' as well to
make it look in the new place. If you set `auto-save-list-file-prefix'
to `nil' in your `.emacs' file, sessions are not recorded for recovery.
File Name Aliases
=================
Symbolic links and hard links both make it possible for several file
names to refer to the same file. Hard links are alternate names that
refer directly to the file; all the names are equally valid, and no one
of them is preferred. By contrast, a symbolic link is a kind of defined
alias: when `foo' is a symbolic link to `bar', you can use either name
to refer to the file, but `bar' is the real name, while `foo' is just
an alias. More complex cases occur when symbolic links point to
directories.
If you visit two names for the same file, normally Emacs makes two
different buffers, but it warns you about the situation.
If you wish to avoid visiting the same file in two buffers under
different names, set the variable `find-file-existing-other-name' to a
non-`nil' value. Then `find-file' uses the existing buffer visiting
the file, no matter which of the file's names you specify.
If the variable `find-file-visit-truename' is non-`nil', then the
file name recorded for a buffer is the file's "truename" (made by
replacing all symbolic links with their target names), rather than the
name you specify. Setting `find-file-visit-truename' also implies the
effect of `find-file-existing-other-name'.
Version Control
===============
"Version control systems" are packages that can record multiple
versions of a source file, usually storing the unchanged parts of the
file just once. Version control systems also record history information
such as the creation time of each version, who created it, and a
description of what was changed in that version.
The Emacs version control interface is called VC. Its commands work
with three version control systems--RCS, CVS and SCCS. The GNU project
recommends RCS and CVS, which are free software and available from the
Free Software Foundation.
Introduction to Version Control
-------------------------------
VC allows you to use a version control system from within Emacs,
integrating the version control operations smoothly with editing. VC
provides a uniform interface to version control, so that regardless of
which version control system is in use, you can use it the same way.
This section provides a general overview of version control, and
describes the version control systems that VC supports. You can skip
this section if you are already familiar with the version control system
you want to use.
Supported Version Control Systems
.................................
VC currently works with three different version control systems or
"back ends": RCS, CVS, and SCCS.
RCS is a free version control system that is available from the Free
Software Foundation. It is perhaps the most mature of the supported
back ends, and the VC commands are conceptually closest to RCS. Almost
everything you can do with RCS can be done through VC.
CVS is built on top of RCS, and extends the features of RCS, allowing
for more sophisticated release management, and concurrent multi-user
development. VC supports basic editing operations under CVS, but for
some less common tasks you still need to call CVS from the command line.
Note also that before using CVS you must set up a repository, which is a
subject too complex to treat here.
SCCS is a proprietary but widely used version control system. In
terms of capabilities, it is the weakest of the three that VC supports.
VC compensates for certain features missing in SCCS (snapshots, for
example) by implementing them itself, but some other VC features, such
as multiple branches, are not available with SCCS. You should use SCCS
only if for some reason you cannot use RCS.
Concepts of Version Control
...........................
When a file is under version control, we also say that it is
"registered" in the version control system. Each registered file has a
corresponding "master file" which represents the file's present state
plus its change history--enough to reconstruct the current version or
any earlier version. Usually the master file also records a "log
entry" for each version, describing in words what was changed in that
version.
The file that is maintained under version control is sometimes called
the "work file" corresponding to its master file. You edit the work
file and make changes in it, as you would with an ordinary file. (With
SCCS and RCS, you must "lock" the file before you start to edit it.)
After you are done with a set of changes, you "check the file in",
which records the changes in the master file, along with a log entry for
them.
With CVS, there are usually multiple work files corresponding to a
single master file--often each user has his own copy. It is also
possible to use RCS in this way, but this is not the usual way to use
RCS.
A version control system typically has some mechanism to coordinate
between users who want to change the same file. One method is
"locking" (analogous to the locking that Emacs uses to detect
simultaneous editing of a file, but distinct from it). The other method
is to merge your changes with other people's changes when you check them
in.
With version control locking, work files are normally read-only so
that you cannot change them. You ask the version control system to make
a work file writable for you by locking it; only one user can do this
at any given time. When you check in your changes, that unlocks the
file, making the work file read-only again. This allows other users to
lock the file to make further changes. SCCS always uses locking, and
RCS normally does.
The other alternative for RCS is to let each user modify the work
file at any time. In this mode, locking is not required, but it is
permitted; check-in is still the way to record a new version.
CVS normally allows each user to modify his own copy of the work file
at any time, but requires merging with changes from other users at
check-in time. However, CVS can also be set up to require locking.
(*note Backend Options::.).
Version Control and the Mode Line
---------------------------------
When you visit a file that is under version control, Emacs indicates
this on the mode line. For example, `RCS-1.3' says that RCS is used
for that file, and the current version is 1.3.
The character between the back-end name and the version number
indicates the version control status of the file. `-' means that the
work file is not locked (if locking is in use), or not modified (if
locking is not in use). `:' indicates that the file is locked, or that
it is modified. If the file is locked by some other user (for
instance, `jim'), that is displayed as `RCS:jim:1.3'.
Basic Editing under Version Control
-----------------------------------
The principal VC command is an all-purpose command that performs
either locking or check-in, depending on the situation.
`C-x C-q'
`C-x v v'
Perform the next logical version control operation on this file.
Strictly speaking, the command for this job is `vc-next-action',
bound to `C-x v v'. However, the normal meaning of `C-x C-q' is to
make a read-only buffer writable, or vice versa; we have extended it to
do the same job properly for files managed by version control, by
performing the appropriate version control operations. When you type
`C-x C-q' on a registered file, it acts like `C-x v v'.
The precise action of this command depends on the state of the file,
and whether the version control system uses locking or not. SCCS and
RCS normally use locking; CVS normally does not use locking.
Basic Version Control with Locking
..................................
If locking is used for the file (as with SCCS, and RCS in its default
mode), `C-x C-q' can either lock a file or check it in:
* If the file is not locked, `C-x C-q' locks it, and makes it
writable so that you can change it.
* If the file is locked by you, and contains changes, `C-x C-q'
checks in the changes. In order to do this, it first reads the
log entry for the new version. *Note Log Buffer::.
* If the file is locked by you, but you have not changed it since you
locked it, `C-x C-q' releases the lock and makes the file read-only
again.
* If the file is locked by some other user, `C-x C-q' asks you
whether you want to "steal the lock" from that user. If you say
yes, the file becomes locked by you, but a message is sent to the
person who had formerly locked the file, to inform him of what has
happened.
These rules also apply when you use CVS in locking mode, except that
there is no such thing as stealing a lock.
Basic Version Control without Locking
.....................................
When there is no locking--the default for CVS--work files are always
writable; you do not need to do anything before you begin to edit a
file. The status indicator on the mode line is `-' if the file is
unmodified; it flips to `:' as soon as you save any changes in the work
file.
Here is what `C-x C-q' does when using CVS:
* If some other user has checked in changes into the master file,
Emacs asks you whether you want to merge those changes into your
own work file (*note Merging::.). You must do this before you can
check in your own changes.
* If there are no new changes in the master file, but you have made
modifications in your work file, `C-x C-q' checks in your changes.
In order to do this, it first reads the log entry for the new
version. *Note Log Buffer::.
* If the file is not modified, the `C-x C-q' does nothing.
These rules also apply when you use RCS in the mode that does not
require locking, except that automatic merging of changes from the
master file is not implemented. Unfortunately, this means that nothing
informs you if another user has checked in changes in the same file
since you began editing it, and when this happens, his changes will be
effectively removed when you check in your version (though they will
remain in the master file, so they will not be entirely lost). You must
therefore verify the current version is unchanged, before you check in
your changes. We hope to eliminate this risk and provide automatic
merging with RCS in a future Emacs version.
In addition, locking is possible with RCS even in this mode, although
it is not required; `C-x C-q' with an unmodified file locks the file,
just as it does with RCS in its normal (locking) mode.
Features of the Log Entry Buffer
................................
When you check in changes, `C-x C-q' first reads a log entry. It
pops up a buffer called `*VC-Log*' for you to enter the log entry.
When you are finished, type `C-c C-c' in the `*VC-Log*' buffer. That
is when check-in really happens.
To abort check-in, just *don't* type `C-c C-c' in that buffer. You
can switch buffers and do other editing. As long as you don't try to
check in another file, the entry you were editing remains in the
`*VC-Log*' buffer, and you can go back to that buffer at any time to
complete the check-in.
If you change several source files for the same reason, it is often
convenient to specify the same log entry for many of the files. To do
this, use the history of previous log entries. The commands `M-n',
`M-p', `M-s' and `M-r' for doing this work just like the minibuffer
history commands (except that these versions are used outside the
minibuffer).
Each time you check in a file, the log entry buffer is put into VC
Log mode, which involves running two hooks: `text-mode-hook' and
`vc-log-mode-hook'. *Note Hooks::.
Examining And Comparing Old Versions
------------------------------------
One of the convenient features of version control is the ability to
examine any version of a file, or compare two versions.
`C-x v ~ VERSION <RET>'
Examine version VERSION of the visited file, in a buffer of its
own.
`C-x v ='
Compare the current buffer contents with the latest checked-in
version of the file.
`C-u C-x v = FILE <RET> OLDVERS <RET> NEWVERS <RET>'
Compare the specified two versions of FILE.
`C-x v g'
Display the result of the CVS annotate command using colors.
To examine an old version in toto, visit the file and then type `C-x
v ~ VERSION <RET>' (`vc-version-other-window'). This puts the text of
version VERSION in a file named `FILENAME.~VERSION~', and visits it in
its own buffer in a separate window. (In RCS, you can also select an
old version and create a branch from it. *Note Branches::.)
But usually it is more convenient to compare two versions of the
file, with the command `C-x v =' (`vc-diff'). Plain `C-x v =' compares
the current buffer contents (saving them in the file if necessary) with
the last checked-in version of the file. `C-u C-x v =', with a numeric
argument, reads a file name and two version numbers, then compares
those versions of the specified file.
If you supply a directory name instead of the name of a registered
file, this command compares the two specified versions of all registered
files in that directory and its subdirectories.
You can specify a checked-in version by its number; an empty input
specifies the current contents of the work file (which may be different
from all the checked-in versions). You can also specify a snapshot name
(*note Snapshots::.) instead of one or both version numbers.
This command works by running the `diff' utility, getting the
options from the variable `diff-switches'. It displays the output in a
special buffer in another window. Unlike the `M-x diff' command, `C-x
v =' does not try to locate the changes in the old and new versions.
This is because normally one or both versions do not exist as files
when you compare them; they exist only in the records of the master
file. *Note Comparing Files::, for more information about `M-x diff'.
For CVS-controlled files, you can display the result of the CVS
annotate command, using colors to enhance the visual appearance. Use
the command `M-x vc-annotate' to do this. Red means new, blue means
old, and intermediate colors indicate intermediate ages. A prefix
argument N specifies a stretch factor for the time scale; it makes each
color cover a period N times as long.
The Secondary Commands of VC
----------------------------
This section explains the secondary commands of VC; those that you
might use once a day.
Registering a File for Version Control
......................................
You can put any file under version control by simply visiting it, and
then typing `C-x v i' (`vc-register').
`C-x v i'
Register the visited file for version control.
To register the file, Emacs must choose which version control system
to use for it. You can specify your choice explicitly by setting
`vc-default-back-end' to `RCS', `CVS' or `SCCS'. Otherwise, if there
is a subdirectory named `RCS', `SCCS', or `CVS', Emacs uses the
corresponding version control system. In the absence of any
specification, the default choice is RCS if RCS is installed, otherwise
SCCS.
If locking is in use, `C-x v i' leaves the file unlocked and
read-only. Type `C-x C-q' if you wish to start editing it. After
registering a file with CVS, you must subsequently commit the initial
version by typing `C-x C-q'.
The initial version number for a newly registered file is 1.1, by
default. You can specify a different default by setting the variable
`vc-default-init-version', or you can give `C-x v i' a numeric
argument; then it reads the initial version number for this particular
file using the minibuffer.
If `vc-initial-comment' is non-`nil', `C-x v i' reads an initial
comment to describe the purpose of this source file. Reading the
initial comment works like reading a log entry (*note Log Buffer::.).
VC Status Commands
..................
`C-x v l'
Display version control state and change history.
To view the detailed version control status and history of a file,
type `C-x v l' (`vc-print-log'). It displays the history of changes to
the current file, including the text of the log entries. The output
appears in a separate window.
Undoing Version Control Actions
...............................
`C-x v u'
Revert the buffer and the file to the last checked-in version.
`C-x v c'
Remove the last-entered change from the master for the visited
file. This undoes your last check-in.
If you want to discard your current set of changes and revert to the
last version checked in, use `C-x v u' (`vc-revert-buffer'). This
leaves the file unlocked; if locking is in use, you must first lock the
file again before you change it again. `C-x v u' requires
confirmation, unless it sees that you haven't made any changes since the
last checked-in version.
`C-x v u' is also the command to unlock a file if you lock it and
then decide not to change it.
To cancel a change that you already checked in, use `C-x v c'
(`vc-cancel-version'). This command discards all record of the most
recent checked-in version. `C-x v c' also offers to revert your work
file and buffer to the previous version (the one that precedes the
version that is deleted).
If you answer `no', VC keeps your changes in the buffer, and locks
the file. The no-revert option is useful when you have checked in a
change and then discover a trivial error in it; you can cancel the
erroneous check-in, fix the error, and check the file in again.
When `C-x v c' does not revert the buffer, it unexpands all version
control headers in the buffer instead (*note Version Headers::.). This
is because the buffer no longer corresponds to any existing version.
If you check it in again, the check-in process will expand the headers
properly for the new version number.
However, it is impossible to unexpand the RCS `$Log$' header
automatically. If you use that header feature, you have to unexpand it
by hand--by deleting the entry for the version that you just canceled.
Be careful when invoking `C-x v c', as it is easy to lose a lot of
work with it. To help you be careful, this command always requires
confirmation with `yes'. Note also that this command is disabled under
CVS, because canceling versions is very dangerous and discouraged with
CVS.
Dired under VC
..............
When you are working on a large program, it is often useful to find
out which files have changed within an entire directory tree, or to view
the status of all files under version control at once, and to perform
version control operations on collections of files. You can use the
command `C-x v d' (`vc-directory') to make a directory listing that
includes only files relevant for version control.
`C-x v d' creates a buffer which uses VC Dired Mode. This looks
much like an ordinary Dired buffer (*note Dired::.); however, normally
it shows only the noteworthy files (those locked or not up-to-date).
This is called "terse display". If you set the variable
`vc-dired-terse-display' to `nil', then VC Dired shows all relevant
files--those managed under version control, plus all subdirectories
("full display"). The command `v t' in a VC Dired buffer toggles
between terse display and full display (*note VC Dired Commands::.).
By default, VC Dired produces a recursive listing of noteworthy or
relevant files at or below the given directory. You can change this by
setting the variable `vc-dired-recurse' to `nil'; then VC Dired shows
only the files in the given directory.
The line for an individual file shows the version control state in
the place of the hard link count, owner, group, and size of the file.
If the file is unmodified, in sync with the master file, the version
control state shown is blank. Otherwise it consists of text in
parentheses. Under RCS and SCCS, the name of the user locking the file
is shown; under CVS, an abbreviated version of the `cvs status' output
is used. Here is an example using RCS:
/home/jim/project:
-rw-r--r-- (jim) Apr 2 23:39 file1
-r--r--r-- Apr 5 20:21 file2
The files `file1' and `file2' are under version control, `file1' is
locked by user jim, and `file2' is unlocked.
Here is an example using CVS:
/home/joe/develop:
-rw-r--r-- (modified) Aug 2 1997 file1.c
-rw-r--r-- Apr 4 20:09 file2.c
-rw-r--r-- (merge) Sep 13 1996 file3.c
Here `file1.c' is modified with respect to the repository, and
`file2.c' is not. `file3.c' is modified, but other changes have also
been checked in to the repository--you need to merge them with the work
file before you can check it in.
When VC Dired displays subdirectories (in the "full" display mode),
it omits some that should never contain any files under version control.
By default, this includes Version Control subdirectories such as `RCS'
and `CVS'; you can customize this by setting the variable
`vc-directory-exclusion-list'.
You can fine-tune VC Dired's format by typing `C-u C-x v d'--as in
ordinary Dired, that allows you to specify additional switches for the
`ls' command.
VC Dired Commands
.................
All the usual Dired commands work normally in VC Dired mode, except
for `v', which is redefined as the version control prefix. You can
invoke VC commands such as `vc-diff' and `vc-print-log' by typing `v
=', or `v l', and so on. Most of these commands apply to the file name
on the current line.
The command `v v' (`vc-next-action') operates on all the marked
files, so that you can lock or check in several files at once. If it
operates on more than one file, it handles each file according to its
current state; thus, it might lock one file, but check in another file.
This could be confusing; it is up to you to avoid confusing behavior
by marking a set of files that are in a similar state.
If any files call for check-in, `v v' reads a single log entry, then
uses it for all the files being checked in. This is convenient for
registering or checking in several files at once, as part of the same
change.
You can toggle between terse display (only locked files, or files not
up-to-date) and full display at any time by typing `v t'
`vc-dired-toggle-terse-mode'. There is also a special command `* l'
(`vc-dired-mark-locked'), which marks all files currently locked (or,
with CVS, all files not up-to-date). Thus, typing `* l t k' is another
way to delete from the buffer all files except those currently locked.
Multiple Branches of a File
---------------------------
One use of version control is to maintain multiple "current"
versions of a file. For example, you might have different versions of a
program in which you are gradually adding various unfinished new
features. Each such independent line of development is called a
"branch". VC allows you to create branches, switch between different
branches, and merge changes from one branch to another. Please note,
however, that branches are only supported for RCS at the moment.
A file's main line of development is usually called the "trunk".
The versions on the trunk are normally numbered 1.1, 1.2, 1.3, etc. At
any such version, you can start an independent branch. A branch
starting at version 1.2 would have version number 1.2.1.1, and
consecutive versions on this branch would have numbers 1.2.1.2,
1.2.1.3, 1.2.1.4, and so on. If there is a second branch also starting
at version 1.2, it would consist of versions 1.2.2.1, 1.2.2.2, 1.2.2.3,
etc.
If you omit the final component of a version number, that is called a
"branch number". It refers to the highest existing version on that
branch--the "head version" of that branch. The branches in the example
above have branch numbers 1.2.1 and 1.2.2.
Switching between Branches
..........................
To switch between branches, type `C-u C-x C-q' and specify the
version number you want to select. This version is then visited
*unlocked* (write-protected), so you can examine it before locking it.
Switching branches in this way is allowed only when the file is not
locked.
You can omit the minor version number, thus giving only the branch
number; this takes you to the head version on the chosen branch. If you
only type <RET>, Emacs goes to the highest version on the trunk.
After you have switched to any branch (including the main branch),
you stay on it for subsequent VC commands, until you explicitly select
some other branch.
Creating New Branches
.....................
To create a new branch from a head version (one that is the latest in
the branch that contains it), first select that version if necessary,
lock it with `C-x C-q', and make whatever changes you want. Then, when
you check in the changes, use `C-u C-x C-q'. This lets you specify the
version number for the new version. You should specify a suitable
branch number for a branch starting at the current version. For
example, if the current version is 2.5, the branch number should be
2.5.1, 2.5.2, and so on, depending on the number of existing branches at
that point.
To create a new branch at an older version (one that is no longer the
head of a branch), first select that version (*note Switching
Branches::.), then lock it with `C-x C-q'. You'll be asked to confirm,
when you lock the old version, that you really mean to create a new
branch--if you say no, you'll be offered a chance to lock the latest
version instead.
Then make your changes and type `C-x C-q' again to check in a new
version. This automatically creates a new branch starting from the
selected version. You need not specially request a new branch, because
that's the only way to add a new version at a point that is not the head
of a branch.
After the branch is created, you "stay" on it. That means that
subsequent check-ins create new versions on that branch. To leave the
branch, you must explicitly select a different version with `C-u C-x
C-q'. To transfer changes from one branch to another, use the merge
command, described in the next section.
Merging Branches
................
When you have finished the changes on a certain branch, you will
often want to incorporate them into the file's main line of development
(the trunk). This is not a trivial operation, because development might
also have proceeded on the trunk, so that you must "merge" the changes
into a file that has already been changed otherwise. VC allows you to
do this (and other things) with the `vc-merge' command.
`C-x v m (vc-merge)'
Merge changes into the work file.
`C-x v m' (`vc-merge') takes a set of changes and merges it into the
current version of the work file. It first asks you for a branch
number or a pair of version numbers in the minibuffer. Then it finds
the changes from that branch, or between the two versions you
specified, and merges them into the current version of the current file.
As an example, suppose that you have finished a certain feature on
branch 1.3.1. In the meantime, development on the trunk has proceeded
to version 1.5. To merge the changes from the branch to the trunk,
first go to the head version of the trunk, by typing `C-u C-x C-q RET'.
Version 1.5 is now current. If locking is used for the file, type
`C-x C-q' to lock version 1.5 so that you can change it. Next, type
`C-x v m 1.3.1 RET'. This takes the entire set of changes on branch
1.3.1 (relative to version 1.3, where the branch started, up to the
last version on the branch) and merges it into the current version of
the work file. You can now check in the changed file, thus creating
version 1.6 containing the changes from the branch.
It is possible to do further editing after merging the branch, before
the next check-in. But it is usually wiser to check in the merged
version, then lock it and make the further changes. This will keep a
better record of the history of changes.
When you merge changes into a file that has itself been modified, the
changes might overlap. We call this situation a "conflict", and
reconciling the conflicting changes is called "resolving a conflict".
Whenever conflicts occur during merging, VC detects them, tells you
about them in the echo area, and asks whether you want help in merging.
If you say yes, it starts an Ediff session (*note Ediff: (ediff)Top.).
If you say no, the conflicting changes are both inserted into the
file, surrounded by "conflict markers". The example below shows how a
conflict region looks; the file is called `name' and the current master
file version with user B's changes in it is 1.11.
<<<<<<< name
USER A'S VERSION
=======
USER B'S VERSION
>>>>>>> 1.11
Then you can resolve the conflicts by editing the file manually. Or
you can type `M-x vc-resolve-conflicts' after visiting the file. This
starts an Ediff session, as described above.
Multi-User Branching
....................
It is often useful for multiple developers to work simultaneously on
different branches of a file. CVS allows this by default; for RCS, it
is possible if you create multiple source directories. Each source
directory should have a link named `RCS' which points to a common
directory of RCS master files. Then each source directory can have its
own choice of selected versions, but all share the same common RCS
records.
This technique works reliably and automatically, provided that the
source files contain RCS version headers (*note Version Headers::.).
The headers enable Emacs to be sure, at all times, which version number
is present in the work file.
If the files do not have version headers, you must instead tell Emacs
explicitly in each session which branch you are working on. To do this,
first find the file, then type `C-u C-x C-q' and specify the correct
branch number. This ensures that Emacs knows which branch it is using
during this particular editing session.
Snapshots
---------
A "snapshot" is a named set of file versions (one for each
registered file) that you can treat as a unit. One important kind of
snapshot is a "release", a (theoretically) stable version of the system
that is ready for distribution to users.
Making and Using Snapshots
..........................
There are two basic commands for snapshots; one makes a snapshot
with a given name, the other retrieves a named snapshot.
`C-x v s NAME <RET>'
Define the last saved versions of every registered file in or
under the current directory as a snapshot named NAME
(`vc-create-snapshot').
`C-x v r NAME <RET>'
For all registered files at or below the current directory level,
select whatever versions correspond to the snapshot NAME
(`vc-retrieve-snapshot').
This command reports an error if any files are locked at or below
the current directory, without changing anything; this is to avoid
overwriting work in progress.
A snapshot uses a very small amount of resources--just enough to
record the list of file names and which version belongs to the
snapshot. Thus, you need not hesitate to create snapshots whenever
they are useful.
You can give a snapshot name as an argument to `C-x v =' or `C-x v
~' (*note Old Versions::.). Thus, you can use it to compare a snapshot
against the current files, or two snapshots against each other, or a
snapshot against a named version.
Snapshot Caveats
................
VC's snapshot facilities are modeled on RCS's named-configuration
support. They use RCS's native facilities for this, so under VC
snapshots made using RCS are visible even when you bypass VC.
For SCCS, VC implements snapshots itself. The files it uses contain
name/file/version-number triples. These snapshots are visible only
through VC.
A snapshot is a set of checked-in versions. So make sure that all
the files are checked in and not locked when you make a snapshot.
File renaming and deletion can create some difficulties with
snapshots. This is not a VC-specific problem, but a general design
issue in version control systems that no one has solved very well yet.
If you rename a registered file, you need to rename its master along
with it (the command `vc-rename-file' does this automatically). If you
are using SCCS, you must also update the records of the snapshot, to
mention the file by its new name (`vc-rename-file' does this, too). An
old snapshot that refers to a master file that no longer exists under
the recorded name is invalid; VC can no longer retrieve it. It would
be beyond the scope of this manual to explain enough about RCS and SCCS
to explain how to update the snapshots by hand.
Using `vc-rename-file' makes the snapshot remain valid for
retrieval, but it does not solve all problems. For example, some of the
files in the program probably refer to others by name. At the very
least, the makefile probably mentions the file that you renamed. If you
retrieve an old snapshot, the renamed file is retrieved under its new
name, which is not the name that the makefile expects. So the program
won't really work as retrieved.
Miscellaneous Commands and Features of VC
-----------------------------------------
This section explains the less-frequently-used features of VC.
Change Logs and VC
..................
If you use RCS or CVS for a program and also maintain a change log
file for it (*note Change Log::.), you can generate change log entries
automatically from the version control log entries:
`C-x v a'
Visit the current directory's change log file and, for registered
files in that directory, create new entries for versions checked
in since the most recent entry in the change log file.
(`vc-update-change-log').
This command works with RCS or CVS only, not with SCCS.
`C-u C-x v a'
As above, but only find entries for the current buffer's file.
`M-1 C-x v a'
As above, but find entries for all the currently visited files
that are maintained with version control. This works only with
RCS, and it puts all entries in the log for the default directory,
which may not be appropriate.
For example, suppose the first line of `ChangeLog' is dated
1999-04-10, and that the only check-in since then was by Nathaniel
Bowditch to `rcs2log' on 1999-05-22 with log text `Ignore log messages
that start with `#'.'. Then `C-x v a' visits `ChangeLog' and inserts
text like this:
1999-05-22 Nathaniel Bowditch <nat@apn.org>
* rcs2log: Ignore log messages that start with `#'.
You can then edit the new change log entry further as you wish.
Unfortunately, timestamps in ChangeLog files are only dates, so some
of the new change log entry may duplicate what's already in ChangeLog.
You will have to remove these duplicates by hand.
Normally, the log entry for file `foo' is displayed as `* foo: TEXT
OF LOG ENTRY'. The `:' after `foo' is omitted if the text of the log
entry starts with `(FUNCTIONNAME): '. For example, if the log entry
for `vc.el' is `(vc-do-command): Check call-process status.', then the
text in `ChangeLog' looks like this:
1999-05-06 Nathaniel Bowditch <nat@apn.org>
* vc.el (vc-do-command): Check call-process status.
When `C-x v a' adds several change log entries at once, it groups
related log entries together if they all are checked in by the same
author at nearly the same time. If the log entries for several such
files all have the same text, it coalesces them into a single entry.
For example, suppose the most recent check-ins have the following log
entries:
* For `vc.texinfo': `Fix expansion typos.'
* For `vc.el': `Don't call expand-file-name.'
* For `vc-hooks.el': `Don't call expand-file-name.'
They appear like this in `ChangeLog':
1999-04-01 Nathaniel Bowditch <nat@apn.org>
* vc.texinfo: Fix expansion typos.
* vc.el, vc-hooks.el: Don't call expand-file-name.
Normally, `C-x v a' separates log entries by a blank line, but you
can mark several related log entries to be clumped together (without an
intervening blank line) by starting the text of each related log entry
with a label of the form `{CLUMPNAME} '. The label itself is not
copied to `ChangeLog'. For example, suppose the log entries are:
* For `vc.texinfo': `{expand} Fix expansion typos.'
* For `vc.el': `{expand} Don't call expand-file-name.'
* For `vc-hooks.el': `{expand} Don't call expand-file-name.'
Then the text in `ChangeLog' looks like this:
1999-04-01 Nathaniel Bowditch <nat@apn.org>
* vc.texinfo: Fix expansion typos.
* vc.el, vc-hooks.el: Don't call expand-file-name.
A log entry whose text begins with `#' is not copied to `ChangeLog'.
For example, if you merely fix some misspellings in comments, you can
log the change with an entry beginning with `#' to avoid putting such
trivia into `ChangeLog'.
Renaming VC Work Files and Master Files
.......................................
When you rename a registered file, you must also rename its master
file correspondingly to get proper results. Use `vc-rename-file' to
rename the source file as you specify, and rename its master file
accordingly. It also updates any snapshots (*note Snapshots::.) that
mention the file, so that they use the new name; despite this, the
snapshot thus modified may not completely work (*note Snapshot
Caveats::.).
You cannot use `vc-rename-file' on a file that is locked by someone
else.
Inserting Version Control Headers
.................................
Sometimes it is convenient to put version identification strings
directly into working files. Certain special strings called "version
headers" are replaced in each successive version by the number of that
version.
If you are using RCS, and version headers are present in your working
files, Emacs can use them to determine the current version and the
locking state of the files. This is more reliable than referring to the
master files, which is done when there are no version headers. Note
that in a multi-branch environment, version headers are necessary to
make VC behave correctly (*note Multi-User Branching::.).
Searching for version headers is controlled by the variable
`vc-consult-headers'. If it is non-`nil', Emacs searches for headers
to determine the version number you are editing. Setting it to `nil'
disables this feature.
You can use the `C-x v h' command (`vc-insert-headers') to insert a
suitable header string.
`C-x v h'
Insert headers in a file for use with your version-control system.
The default header string is `$Id$' for RCS and `%W%' for SCCS. You
can specify other headers to insert by setting the variable
`vc-header-alist'. Its value is a list of elements of the form
`(PROGRAM . STRING)' where PROGRAM is `RCS' or `SCCS' and STRING is the
string to use.
Instead of a single string, you can specify a list of strings; then
each string in the list is inserted as a separate header on a line of
its own.
It is often necessary to use "superfluous" backslashes when writing
the strings that you put in this variable. This is to prevent the
string in the constant from being interpreted as a header itself if the
Emacs Lisp file containing it is maintained with version control.
Each header is inserted surrounded by tabs, inside comment
delimiters, on a new line at point. Normally the ordinary comment
start and comment end strings of the current mode are used, but for
certain modes, there are special comment delimiters for this purpose;
the variable `vc-comment-alist' specifies them. Each element of this
list has the form `(MODE STARTER ENDER)'.
The variable `vc-static-header-alist' specifies further strings to
add based on the name of the buffer. Its value should be a list of
elements of the form `(REGEXP . FORMAT)'. Whenever REGEXP matches the
buffer name, FORMAT is inserted as part of the header. A header line
is inserted for each element that matches the buffer name, and for each
string specified by `vc-header-alist'. The header line is made by
processing the string from `vc-header-alist' with the format taken from
the element. The default value for `vc-static-header-alist' is as
follows:
(("\\.c$" .
"\n#ifndef lint\nstatic char vcid[] = \"\%s\";\n\
#endif /* lint */\n"))
It specifies insertion of text of this form:
#ifndef lint
static char vcid[] = "STRING";
#endif /* lint */
Note that the text above starts with a blank line.
If you use more than one version header in a file, put them close
together in the file. The mechanism in `revert-buffer' that preserves
markers may not handle markers positioned between two version headers.
Customizing VC
--------------
There are many ways of customizing VC. The options you can set fall
into four categories, described in the following sections.
Options for VC Backends
.......................
You can tell RCS and CVS whether to use locking for a file or not
(*note VC Concepts::., for a description of locking). VC automatically
recognizes what you have chosen, and behaves accordingly.
For RCS, the default is to use locking, but there is a mode called
"non-strict locking" in which you can check-in changes without locking
the file first. Use `rcs -U' to switch to non-strict locking for a
particular file, see the `rcs' manpage for details.
Under CVS, the default is not to use locking; anyone can change a
work file at any time. However, there are ways to restrict this,
resulting in behavior that resembles locking.
For one thing, you can set the `CVSREAD' environment variable to an
arbitrary value. If this variable is defined, CVS makes your work
files read-only by default. In Emacs, you must type `C-x C-q' to make
the file writeable, so that editing works in fact similar as if locking
was used. Note however, that no actual locking is performed, so
several users can make their files writeable at the same time. When
setting `CVSREAD' for the first time, make sure to check out all your
modules anew, so that the file protections are set correctly.
Another way to achieve something similar to locking is to use the
"watch" feature of CVS. If a file is being watched, CVS makes it
read-only by default, and you must also use `C-x C-q' in Emacs to make
it writable. VC calls `cvs edit' to make the file writeable, and CVS
takes care to notify other developers of the fact that you intend to
change the file. See the CVS documentation for details on using the
watch feature.
You can turn off use of VC for CVS-managed files by setting the
variable `vc-handle-cvs' to `nil'. If you do this, Emacs treats these
files as if they were not registered, and the VC commands are not
available for them. You must do all CVS operations manually.
VC Workfile Handling
....................
Emacs normally does not save backup files for source files that are
maintained with version control. If you want to make backup files even
for files that use version control, set the variable
`vc-make-backup-files' to a non-`nil' value.
Normally the work file exists all the time, whether it is locked or
not. If you set `vc-keep-workfiles' to `nil', then checking in a new
version with `C-x C-q' deletes the work file; but any attempt to visit
the file with Emacs creates it again. (With CVS, work files are always
kept.)
Editing a version-controlled file through a symbolic link can be
dangerous. It bypasses the version control system--you can edit the
file without locking it, and fail to check your changes in. Also, your
changes might overwrite those of another user. To protect against
this, VC checks each symbolic link that you visit, to see if it points
to a file under version control.
The variable `vc-follow-symlinks' controls what to do when a
symbolic link points to a version-controlled file. If it is `nil', VC
only displays a warning message. If it is `t', VC automatically
follows the link, and visits the real file instead, telling you about
this in the echo area. If the value is `ask' (the default), VC asks
you each time whether to follow the link.
VC Status Retrieval
...................
When deducing the locked/unlocked state of a file, VC first looks for
an RCS version header string in the file (*note Version Headers::.). If
there is no header string, or if you are using SCCS, VC normally looks
at the file permissions of the work file; this is fast. But there might
be situations when the file permissions cannot be trusted. In this case
the master file has to be consulted, which is rather expensive. Also
the master file can only tell you *if* there's any lock on the file,
but not whether your work file really contains that locked version.
You can tell VC not to use version headers to determine lock status
by setting `vc-consult-headers' to `nil'. VC then always uses the file
permissions (if it can trust them), or else checks the master file.
You can specify the criterion for whether to trust the file
permissions by setting the variable `vc-mistrust-permissions'. Its
value can be `t' (always mistrust the file permissions and check the
master file), `nil' (always trust the file permissions), or a function
of one argument which makes the decision. The argument is the
directory name of the `RCS', `CVS' or `SCCS' subdirectory. A non-`nil'
value from the function says to mistrust the file permissions. If you
find that the file permissions of work files are changed erroneously,
set `vc-mistrust-permissions' to `t'. Then VC always checks the master
file to determine the file's status.
VC Command Execution
....................
If `vc-suppress-confirm' is non-`nil', then `C-x C-q' and `C-x v i'
can save the current buffer without asking, and `C-x v u' also operates
without asking for confirmation. (This variable does not affect `C-x v
c'; that operation is so drastic that it should always ask for
confirmation.)
VC mode does much of its work by running the shell commands for RCS,
CVS and SCCS. If `vc-command-messages' is non-`nil', VC displays
messages to indicate which shell commands it runs, and additional
messages when the commands finish.
You can specify additional directories to search for version control
programs by setting the variable `vc-path'. These directories are
searched before the usual search path. But the proper files are usually
found automatically.
File Directories
================
The file system groups files into "directories". A "directory
listing" is a list of all the files in a directory. Emacs provides
commands to create and delete directories, and to make directory
listings in brief format (file names only) and verbose format (sizes,
dates, and authors included). There is also a directory browser called
Dired; see *Note Dired::.
`C-x C-d DIR-OR-PATTERN <RET>'
Display a brief directory listing (`list-directory').
`C-u C-x C-d DIR-OR-PATTERN <RET>'
Display a verbose directory listing.
`M-x make-directory <RET> DIRNAME <RET>'
Create a new directory named DIRNAME.
`M-x delete-directory <RET> DIRNAME <RET>'
Delete the directory named DIRNAME. It must be empty, or you get
an error.
The command to display a directory listing is `C-x C-d'
(`list-directory'). It reads using the minibuffer a file name which is
either a directory to be listed or a wildcard-containing pattern for
the files to be listed. For example,
C-x C-d /u2/emacs/etc <RET>
lists all the files in directory `/u2/emacs/etc'. Here is an example
of specifying a file name pattern:
C-x C-d /u2/emacs/src/*.c <RET>
Normally, `C-x C-d' prints a brief directory listing containing just
file names. A numeric argument (regardless of value) tells it to make
a verbose listing including sizes, dates, and authors (like `ls -l').
The text of a directory listing is obtained by running `ls' in an
inferior process. Two Emacs variables control the switches passed to
`ls': `list-directory-brief-switches' is a string giving the switches
to use in brief listings (`"-CF"' by default), and
`list-directory-verbose-switches' is a string giving the switches to
use in a verbose listing (`"-l"' by default).
Comparing Files
===============
The command `M-x diff' compares two files, displaying the
differences in an Emacs buffer named `*Diff*'. It works by running the
`diff' program, using options taken from the variable `diff-switches',
whose value should be a string.
The buffer `*Diff*' has Compilation mode as its major mode, so you
can use `C-x `' to visit successive changed locations in the two source
files. You can also move to a particular hunk of changes and type
<RET> or `C-c C-c', or click `Mouse-2' on it, to move to the
corresponding source location. You can also use the other special
commands of Compilation mode: <SPC> and <DEL> for scrolling, and `M-p'
and `M-n' for cursor motion. *Note Compilation::.
The command `M-x diff-backup' compares a specified file with its most
recent backup. If you specify the name of a backup file, `diff-backup'
compares it with the source file that it is a backup of.
The command `M-x compare-windows' compares the text in the current
window with that in the next window. Comparison starts at point in each
window, and each starting position is pushed on the mark ring in its
respective buffer. Then point moves forward in each window, a character
at a time, until a mismatch between the two windows is reached. Then
the command is finished. For more information about windows in Emacs,
*Note Windows::.
With a numeric argument, `compare-windows' ignores changes in
whitespace. If the variable `compare-ignore-case' is non-`nil', it
ignores differences in case as well.
See also *Note Emerge::, for convenient facilities for merging two
similar files.
Miscellaneous File Operations
=============================
Emacs has commands for performing many other operations on files.
All operate on one file; they do not accept wildcard file names.
`M-x view-file' allows you to scan or read a file by sequential
screenfuls. It reads a file name argument using the minibuffer. After
reading the file into an Emacs buffer, `view-file' displays the
beginning. You can then type <SPC> to scroll forward one windowful, or
<DEL> to scroll backward. Various other commands are provided for
moving around in the file, but none for changing it; type `?' while
viewing for a list of them. They are mostly the same as normal Emacs
cursor motion commands. To exit from viewing, type `q'. The commands
for viewing are defined by a special major mode called View mode.
A related command, `M-x view-buffer', views a buffer already present
in Emacs. *Note Misc Buffer::.
`M-x insert-file' inserts a copy of the contents of the specified
file into the current buffer at point, leaving point unchanged before
the contents and the mark after them.
`M-x write-region' is the inverse of `M-x insert-file'; it copies
the contents of the region into the specified file. `M-x
append-to-file' adds the text of the region to the end of the specified
file. *Note Accumulating Text::.
`M-x delete-file' deletes the specified file, like the `rm' command
in the shell. If you are deleting many files in one directory, it may
be more convenient to use Dired (*note Dired::.).
`M-x rename-file' reads two file names OLD and NEW using the
minibuffer, then renames file OLD as NEW. If a file named NEW already
exists, you must confirm with `yes' or renaming is not done; this is
because renaming causes the old meaning of the name NEW to be lost. If
OLD and NEW are on different file systems, the file OLD is copied and
deleted.
The similar command `M-x add-name-to-file' is used to add an
additional name to an existing file without removing its old name. The
new name must belong on the same file system that the file is on.
`M-x copy-file' reads the file OLD and writes a new file named NEW
with the same contents. Confirmation is required if a file named NEW
already exists, because copying has the consequence of overwriting the
old contents of the file NEW.
`M-x make-symbolic-link' reads two file names TARGET and LINKNAME,
then creates a symbolic link named LINKNAME and pointing at TARGET.
The effect is that future attempts to open file LINKNAME will refer to
whatever file is named TARGET at the time the opening is done, or will
get an error if the name TARGET is not in use at that time. This
command does not expand the argument TARGET, so that it allows you to
specify a relative name as the target of the link.
Confirmation is required when creating the link if LINKNAME is in
use. Note that not all systems support symbolic links.
Accessing Compressed Files
==========================
Emacs comes with a library that can automatically uncompress
compressed files when you visit them, and automatically recompress them
if you alter them and save them. To enable this feature, type the
command `M-x auto-compression-mode'.
When automatic compression (which implies automatic uncompression as
well) is enabled, Emacs recognizes compressed files by their file names.
File names ending in `.gz' indicate a file compressed with `gzip'.
Other endings indicate other compression programs.
Automatic uncompression and compression apply to all the operations
in which Emacs uses the contents of a file. This includes visiting it,
saving it, inserting its contents into a buffer, loading it, and byte
compiling it.
Remote Files
============
You can refer to files on other machines using a special file name
syntax:
/HOST:FILENAME
/USER@HOST:FILENAME
When you do this, Emacs uses the FTP program to read and write files on
the specified host. It logs in through FTP using your user name or the
name USER. It may ask you for a password from time to time; this is
used for logging in on HOST.
Normally, if you do not specify a user name in a remote file name,
that means to use your own user name. But if you set the variable
`ange-ftp-default-user' to a string, that string is used instead. (The
Emacs package that implements FTP file access is called `ange-ftp'.)
You can entirely turn off the FTP file name feature by setting the
variable `file-name-handler-alist' to `nil'.
Quoted File Names
=================
You can "quote" an absolute file name to prevent special characters
and syntax in it from having their special effects. The way to do this
is to add `/:' at the beginning.
For example, you can quote a local file name which appears remote, to
prevent it from being treated as a remote file name. Thus, if you have
a directory named `/foo:' and a file named `bar' in it, you can refer
to that file in Emacs as `/:/foo:/bar'.
`/:' can also prevent `~' from being treated as a special character
for a user's home directory. For example, `/:/tmp/~hack' refers to a
file whose name is `~hack' in directory `/tmp'.
Likewise, quoting with `/:' is one way to enter in the minibuffer a
file name that contains `$'. However, the `/:' must be at the
beginning of the buffer in order to quote `$'.
You can also quote wildcard characters with `/:', for visiting. For
example, `/:/tmp/foo*bar' visits the file `/tmp/foo*bar'. However, in
most cases you can simply type the wildcard characters for themselves.
For example, if the only file name in `/tmp' that starts with `foo' and
ends with `bar' is `foo*bar', then specifying `/tmp/foo*bar' will visit
just `/tmp/foo*bar'.
Using Multiple Buffers
**********************
The text you are editing in Emacs resides in an object called a
"buffer". Each time you visit a file, a buffer is created to hold the
file's text. Each time you invoke Dired, a buffer is created to hold
the directory listing. If you send a message with `C-x m', a buffer
named `*mail*' is used to hold the text of the message. When you ask
for a command's documentation, that appears in a buffer called `*Help*'.
At any time, one and only one buffer is "selected". It is also
called the "current buffer". Often we say that a command operates on
"the buffer" as if there were only one; but really this means that the
command operates on the selected buffer (most commands do).
When Emacs has multiple windows, each window has a chosen buffer
which is displayed there, but at any time only one of the windows is
selected and its chosen buffer is the selected buffer. Each window's
mode line displays the name of the buffer that the window is displaying
(*note Windows::.).
Each buffer has a name, which can be of any length, and you can
select any buffer by giving its name. Most buffers are made by
visiting files, and their names are derived from the files' names. But
you can also create an empty buffer with any name you want. A newly
started Emacs has a buffer named `*scratch*' which can be used for
evaluating Lisp expressions in Emacs. The distinction between upper
and lower case matters in buffer names.
Each buffer records individually what file it is visiting, whether
it is modified, and what major mode and minor modes are in effect in it
(*note Major Modes::.). Any Emacs variable can be made "local to" a
particular buffer, meaning its value in that buffer can be different
from the value in other buffers. *Note Locals::.
Creating and Selecting Buffers
==============================
`C-x b BUFFER <RET>'
Select or create a buffer named BUFFER (`switch-to-buffer').
`C-x 4 b BUFFER <RET>'
Similar, but select BUFFER in another window
(`switch-to-buffer-other-window').
`C-x 5 b BUFFER <RET>'
Similar, but select BUFFER in a separate frame
(`switch-to-buffer-other-frame').
To select the buffer named BUFNAME, type `C-x b BUFNAME <RET>'.
This runs the command `switch-to-buffer' with argument BUFNAME. You
can use completion on an abbreviation for the buffer name you want
(*note Completion::.). An empty argument to `C-x b' specifies the most
recently selected buffer that is not displayed in any window.
Most buffers are created by visiting files, or by Emacs commands that
want to display some text, but you can also create a buffer explicitly
by typing `C-x b BUFNAME <RET>'. This makes a new, empty buffer that
is not visiting any file, and selects it for editing. Such buffers are
used for making notes to yourself. If you try to save one, you are
asked for the file name to use. The new buffer's major mode is
determined by the value of `default-major-mode' (*note Major Modes::.).
Note that `C-x C-f', and any other command for visiting a file, can
also be used to switch to an existing file-visiting buffer. *Note
Visiting::.
Emacs uses buffer names that start with a space for internal
purposes. It treats these buffers specially in minor ways--for
example, by default they do not record undo information. It is best to
avoid using such buffer names yourself.
Listing Existing Buffers
========================
`C-x C-b'
List the existing buffers (`list-buffers').
To display a list of all the buffers that exist, type `C-x C-b'.
Each line in the list shows one buffer's name, major mode and visited
file. The buffers are listed in the order that they were current; the
buffers that were current most recently come first.
`*' at the beginning of a line indicates the buffer is "modified."
If several buffers are modified, it may be time to save some with `C-x
s' (*note Saving::.). `%' indicates a read-only buffer. `.' marks the
selected buffer. Here is an example of a buffer list:
MR Buffer Size Mode File
-- ------ ---- ---- ----
.* emacs.tex 383402 Texinfo /u2/emacs/man/emacs.tex
*Help* 1287 Fundamental
files.el 23076 Emacs-Lisp /u2/emacs/lisp/files.el
% RMAIL 64042 RMAIL /u/rms/RMAIL
*% man 747 Dired /u2/emacs/man/
net.emacs 343885 Fundamental /u/rms/net.emacs
fileio.c 27691 C /u2/emacs/src/fileio.c
NEWS 67340 Text /u2/emacs/etc/NEWS
*scratch* 0 Lisp Interaction
Note that the buffer `*Help*' was made by a help request; it is not
visiting any file. The buffer `man' was made by Dired on the directory
`/u2/emacs/man/'.
Miscellaneous Buffer Operations
===============================
`C-x C-q'
Toggle read-only status of buffer (`vc-toggle-read-only').
`M-x rename-buffer <RET> NAME <RET>'
Change the name of the current buffer.
`M-x rename-uniquely'
Rename the current buffer by adding `<NUMBER>' to the end.
`M-x view-buffer <RET> BUFFER <RET>'
Scroll through buffer BUFFER.
A buffer can be "read-only", which means that commands to change its
contents are not allowed. The mode line indicates read-only buffers
with `%%' or `%*' near the left margin. Read-only buffers are usually
made by subsystems such as Dired and Rmail that have special commands
to operate on the text; also by visiting a file whose access control
says you cannot write it.
If you wish to make changes in a read-only buffer, use the command
`C-x C-q' (`vc-toggle-read-only'). It makes a read-only buffer
writable, and makes a writable buffer read-only. In most cases, this
works by setting the variable `buffer-read-only', which has a local
value in each buffer and makes the buffer read-only if its value is
non-`nil'. If the file is maintained with version control, `C-x C-q'
works through the version control system to change the read-only status
of the file as well as the buffer. *Note Version Control::.
`M-x rename-buffer' changes the name of the current buffer. Specify
the new name as a minibuffer argument. There is no default. If you
specify a name that is in use for some other buffer, an error happens
and no renaming is done.
`M-x rename-uniquely' renames the current buffer to a similar name
with a numeric suffix added to make it both different and unique. This
command does not need an argument. It is useful for creating multiple
shell buffers: if you rename the `*Shell*' buffer, then do `M-x shell'
again, it makes a new shell buffer named `*Shell*'; meanwhile, the old
shell buffer continues to exist under its new name. This method is
also good for mail buffers, compilation buffers, and most Emacs
features that create special buffers with particular names.
`M-x view-buffer' is much like `M-x view-file' (*note Misc File
Ops::.) except that it examines an already existing Emacs buffer. View
mode provides commands for scrolling through the buffer conveniently
but not for changing it. When you exit View mode with `q', that
switches back to the buffer (and the position) which was previously
displayed in the window. Alternatively, if you exit View mode with
`e', the buffer and the value of point that resulted from your perusal
remain in effect.
The commands `M-x append-to-buffer' and `M-x insert-buffer' can be
used to copy text from one buffer to another. *Note Accumulating
Text::.
Killing Buffers
===============
If you continue an Emacs session for a while, you may accumulate a
large number of buffers. You may then find it convenient to "kill" the
buffers you no longer need. On most operating systems, killing a
buffer releases its space back to the operating system so that other
programs can use it. Here are some commands for killing buffers:
`C-x k BUFNAME <RET>'
Kill buffer BUFNAME (`kill-buffer').
`M-x kill-some-buffers'
Offer to kill each buffer, one by one.
`C-x k' (`kill-buffer') kills one buffer, whose name you specify in
the minibuffer. The default, used if you type just <RET> in the
minibuffer, is to kill the current buffer. If you kill the current
buffer, another buffer is selected; one that has been selected recently
but does not appear in any window now. If you ask to kill a
file-visiting buffer that is modified (has unsaved editing), then you
must confirm with `yes' before the buffer is killed.
The command `M-x kill-some-buffers' asks about each buffer, one by
one. An answer of `y' means to kill the buffer. Killing the current
buffer or a buffer containing unsaved changes selects a new buffer or
asks for confirmation just like `kill-buffer'.
The buffer menu feature (*note Several Buffers::.) is also convenient
for killing various buffers.
If you want to do something special every time a buffer is killed,
you can add hook functions to the hook `kill-buffer-hook' (*note
Hooks::.).
If you run one Emacs session for a period of days, as many people do,
it can fill up with buffers that you used several days ago. The command
`M-x clean-buffer-list' is a convenient way to purge them; it kills all
the unmodified buffers that you have not used for a long time. An
ordinary buffer is killed if it has not been displayed for three days;
however, you can specify certain buffers that should never be killed
automatically, and others that should be killed if they have been unused
for a mere hour.
You can also have this buffer purging done for you, every day at
midnight, by enabling Midnight mode. Midnight mode operates each day at
midnight; at that time, it runs `clean-buffer-list', or whichever
functions you have placed in the normal hook `midnight-hook' (*note
Hooks::.).
To enable Midnight mode, use the Customization buffer to set the
variable `midnight-mode' to `t'. *Note Easy Customization::.
Operating on Several Buffers
============================
The "buffer-menu" facility is like a "Dired for buffers"; it allows
you to request operations on various Emacs buffers by editing an Emacs
buffer containing a list of them. You can save buffers, kill them
(here called "deleting" them, for consistency with Dired), or display
them.
`M-x buffer-menu'
Begin editing a buffer listing all Emacs buffers.
The command `buffer-menu' writes a list of all Emacs buffers into
the buffer `*Buffer List*', and selects that buffer in Buffer Menu
mode. The buffer is read-only, and can be changed only through the
special commands described in this section. The usual Emacs cursor
motion commands can be used in the `*Buffer List*' buffer. The
following commands apply to the buffer described on the current line.
`d'
Request to delete (kill) the buffer, then move down. The request
shows as a `D' on the line, before the buffer name. Requested
deletions take place when you type the `x' command.
`C-d'
Like `d' but move up afterwards instead of down.
`s'
Request to save the buffer. The request shows as an `S' on the
line. Requested saves take place when you type the `x' command.
You may request both saving and deletion for the same buffer.
`x'
Perform previously requested deletions and saves.
`u'
Remove any request made for the current line, and move down.
`<DEL>'
Move to previous line and remove any request made for that line.
The `d', `C-d', `s' and `u' commands to add or remove flags also
move down (or up) one line. They accept a numeric argument as a repeat
count.
These commands operate immediately on the buffer listed on the
current line:
`~'
Mark the buffer "unmodified." The command `~' does this
immediately when you type it.
`%'
Toggle the buffer's read-only flag. The command `%' does this
immediately when you type it.
`t'
Visit the buffer as a tags table. *Note Select Tags Table::.
There are also commands to select another buffer or buffers:
`q'
Quit the buffer menu--immediately display the most recent formerly
visible buffer in its place.
`<RET>'
`f'
Immediately select this line's buffer in place of the `*Buffer
List*' buffer.
`o'
Immediately select this line's buffer in another window as if by
`C-x 4 b', leaving `*Buffer List*' visible.
`C-o'
Immediately display this line's buffer in another window, but don't
select the window.
`1'
Immediately select this line's buffer in a full-screen window.
`2'
Immediately set up two windows, with this line's buffer in one,
and the previously selected buffer (aside from the buffer `*Buffer
List*') in the other.
`b'
Bury the buffer listed on this line.
`m'
Mark this line's buffer to be displayed in another window if you
exit with the `v' command. The request shows as a `>' at the
beginning of the line. (A single buffer may not have both a delete
request and a display request.)
`v'
Immediately select this line's buffer, and also display in other
windows any buffers previously marked with the `m' command. If
you have not marked any buffers, this command is equivalent to `1'.
All that `buffer-menu' does directly is create and switch to a
suitable buffer, and turn on Buffer Menu mode. Everything else
described above is implemented by the special commands provided in
Buffer Menu mode. One consequence of this is that you can switch from
the `*Buffer List*' buffer to another Emacs buffer, and edit there.
You can reselect the `*Buffer List*' buffer later, to perform the
operations already requested, or you can kill it, or pay no further
attention to it.
The only difference between `buffer-menu' and `list-buffers' is that
`buffer-menu' switches to the `*Buffer List*' buffer in the selected
window; `list-buffers' displays it in another window. If you run
`list-buffers' (that is, type `C-x C-b') and select the buffer list
manually, you can use all of the commands described here.
The buffer `*Buffer List*' is not updated automatically when buffers
are created and killed; its contents are just text. If you have
created, deleted or renamed buffers, the way to update `*Buffer List*'
to show what you have done is to type `g' (`revert-buffer') or repeat
the `buffer-menu' command.
Indirect Buffers
================
An "indirect buffer" shares the text of some other buffer, which is
called the "base buffer" of the indirect buffer. In some ways it is
the analogue, for buffers, of a symbolic link between files.
`M-x make-indirect-buffer BASE-BUFFER <RET> INDIRECT-NAME <RET>'
Create an indirect buffer named INDIRECT-NAME whose base buffer is
BASE-BUFFER.
The text of the indirect buffer is always identical to the text of
its base buffer; changes made by editing either one are visible
immediately in the other. But in all other respects, the indirect
buffer and its base buffer are completely separate. They have
different names, different values of point, different narrowing,
different markers, different major modes, and different local variables.
An indirect buffer cannot visit a file, but its base buffer can. If
you try to save the indirect buffer, that actually works by saving the
base buffer. Killing the base buffer effectively kills the indirect
buffer, but killing an indirect buffer has no effect on its base buffer.
One way to use indirect buffers is to display multiple views of an
outline. *Note Outline Views::.
Multiple Windows
****************
Emacs can split a frame into two or many windows. Multiple windows
can display parts of different buffers, or different parts of one
buffer. Multiple frames always imply multiple windows, because each
frame has its own set of windows. Each window belongs to one and only
one frame.
Concepts of Emacs Windows
=========================
Each Emacs window displays one Emacs buffer at any time. A single
buffer may appear in more than one window; if it does, any changes in
its text are displayed in all the windows where it appears. But the
windows showing the same buffer can show different parts of it, because
each window has its own value of point.
At any time, one of the windows is the "selected window"; the buffer
this window is displaying is the current buffer. The terminal's cursor
shows the location of point in this window. Each other window has a
location of point as well, but since the terminal has only one cursor
there is no way to show where those locations are. When multiple
frames are visible in X Windows, each frame has a cursor which appears
in the frame's selected window. The cursor in the selected frame is
solid; the cursor in other frames is a hollow box.
Commands to move point affect the value of point for the selected
Emacs window only. They do not change the value of point in any other
Emacs window, even one showing the same buffer. The same is true for
commands such as `C-x b' to change the selected buffer in the selected
window; they do not affect other windows at all. However, there are
other commands such as `C-x 4 b' that select a different window and
switch buffers in it. Also, all commands that display information in a
window, including (for example) `C-h f' (`describe-function') and `C-x
C-b' (`list-buffers'), work by switching buffers in a nonselected window
without affecting the selected window.
When multiple windows show the same buffer, they can have different
regions, because they can have different values of point. However,
they all have the same value for the mark, because each buffer has only
one mark position.
Each window has its own mode line, which displays the buffer name,
modification status and major and minor modes of the buffer that is
displayed in the window. *Note Mode Line::, for full details on the
mode line.
Splitting Windows
=================
`C-x 2'
Split the selected window into two windows, one above the other
(`split-window-vertically').
`C-x 3'
Split the selected window into two windows positioned side by side
(`split-window-horizontally').
`C-Mouse-2'
In the mode line or scroll bar of a window, split that window.
The command `C-x 2' (`split-window-vertically') breaks the selected
window into two windows, one above the other. Both windows start out
displaying the same buffer, with the same value of point. By default
the two windows each get half the height of the window that was split; a
numeric argument specifies how many lines to give to the top window.
`C-x 3' (`split-window-horizontally') breaks the selected window
into two side-by-side windows. A numeric argument specifies how many
columns to give the one on the left. A line of vertical bars separates
the two windows. Windows that are not the full width of the screen
have mode lines, but they are truncated. On terminals where Emacs does
not support highlighting, truncated mode lines sometimes do not appear
in inverse video.
You can split a window horizontally or vertically by clicking
`C-Mouse-2' in the mode line or the scroll bar. The line of splitting
goes through the place where you click: if you click on the mode line,
the new scroll bar goes above the spot; if you click in the scroll bar,
the mode line of the split window is side by side with your click.
When a window is less than the full width, text lines too long to
fit are frequent. Continuing all those lines might be confusing. The
variable `truncate-partial-width-windows' can be set non-`nil' to force
truncation in all windows less than the full width of the screen,
independent of the buffer being displayed and its value for
`truncate-lines'. *Note Continuation Lines::.
Horizontal scrolling is often used in side-by-side windows. *Note
Display::.
If `split-window-keep-point' is non-`nil', the default, both of the
windows resulting from `C-x 2' inherit the value of point from the
window that was split. This means that scrolling is inevitable. If
this variable is `nil', then `C-x 2' tries to avoid shifting any text
the screen, by putting point in each window at a position already
visible in the window. It also selects whichever window contain the
screen line that the cursor was previously on. Some users prefer the
latter mode on slow terminals.
Using Other Windows
===================
`C-x o'
Select another window (`other-window'). That is `o', not zero.
`C-M-v'
Scroll the next window (`scroll-other-window').
`M-x compare-windows'
Find next place where the text in the selected window does not
match the text in the next window.
`Mouse-1'
`Mouse-1', in a window's mode line, selects that window but does
not move point in it (`mouse-select-window').
To select a different window, click with `Mouse-1' on its mode line.
With the keyboard, you can switch windows by typing `C-x o'
(`other-window'). That is an `o', for `other', not a zero. When there
are more than two windows, this command moves through all the windows
in a cyclic order, generally top to bottom and left to right. After
the rightmost and bottommost window, it goes back to the one at the
upper left corner. A numeric argument means to move several steps in
the cyclic order of windows. A negative argument moves around the
cycle in the opposite order. When the minibuffer is active, the
minibuffer is the last window in the cycle; you can switch from the
minibuffer window to one of the other windows, and later switch back and
finish supplying the minibuffer argument that is requested. *Note
Minibuffer Edit::.
The usual scrolling commands (*note Display::.) apply to the selected
window only, but there is one command to scroll the next window.
`C-M-v' (`scroll-other-window') scrolls the window that `C-x o' would
select. It takes arguments, positive and negative, like `C-v'. (In
the minibuffer, `C-M-v' scrolls the window that contains the minibuffer
help display, if any, rather than the next window in the standard
cyclic order.)
The command `M-x compare-windows' lets you compare two files or
buffers visible in two windows, by moving through them to the next
mismatch. *Note Comparing Files::, for details.
Displaying in Another Window
============================
`C-x 4' is a prefix key for commands that select another window
(splitting the window if there is only one) and select a buffer in that
window. Different `C-x 4' commands have different ways of finding the
buffer to select.
`C-x 4 b BUFNAME <RET>'
Select buffer BUFNAME in another window. This runs
`switch-to-buffer-other-window'.
`C-x 4 C-o BUFNAME <RET>'
Display buffer BUFNAME in another window, but don't select that
buffer or that window. This runs `display-buffer'.
`C-x 4 f FILENAME <RET>'
Visit file FILENAME and select its buffer in another window. This
runs `find-file-other-window'. *Note Visiting::.
`C-x 4 d DIRECTORY <RET>'
Select a Dired buffer for directory DIRECTORY in another window.
This runs `dired-other-window'. *Note Dired::.
`C-x 4 m'
Start composing a mail message in another window. This runs
`mail-other-window'; its same-window analogue is `C-x m' (*note
Sending Mail::.).
`C-x 4 .'
Find a tag in the current tags table, in another window. This runs
`find-tag-other-window', the multiple-window variant of `M-.'
(*note Tags::.).
`C-x 4 r FILENAME <RET>'
Visit file FILENAME read-only, and select its buffer in another
window. This runs `find-file-read-only-other-window'. *Note
Visiting::.
Forcing Display in the Same Window
==================================
Certain Emacs commands switch to a specific buffer with special
contents. For example, `M-x shell' switches to a buffer named
`*Shell*'. By convention, all these commands are written to pop up the
buffer in a separate window. But you can specify that certain of these
buffers should appear in the selected window.
If you add a buffer name to the list `same-window-buffer-names', the
effect is that such commands display that particular buffer by
switching to it in the selected window. For example, if you add the
element `"*grep*"' to the list, the `grep' command will display its
output buffer in the selected window.
The default value of `same-window-buffer-names' is not `nil': it
specifies buffer names `*info*', `*mail*' and `*shell*' (as well as
others used by more obscure Emacs packages). This is why `M-x shell'
normally switches to the `*shell*' buffer in the selected window. If
you delete this element from the value of `same-window-buffer-names',
the behavior of `M-x shell' will change--it will pop up the buffer in
another window instead.
You can specify these buffers more generally with the variable
`same-window-regexps'. Set it to a list of regular expressions; then
any buffer whose name matches one of those regular expressions is
displayed by switching to it in the selected window. (Once again, this
applies only to buffers that normally get displayed for you in a
separate window.) The default value of this variable specifies Telnet
and rlogin buffers.
An analogous feature lets you specify buffers which should be
displayed in their own individual frames. *Note Special Buffer
Frames::.
Deleting and Rearranging Windows
================================
`C-x 0'
Delete the selected window (`delete-window'). The last character
in this key sequence is a zero.
`C-x 1'
Delete all windows in the selected frame except the selected window
(`delete-other-windows').
`C-x 4 0'
Delete the selected window and kill the buffer that was showing in
it (`kill-buffer-and-window'). The last character in this key
sequence is a zero.
`C-x ^'
Make selected window taller (`enlarge-window').
`C-x }'
Make selected window wider (`enlarge-window-horizontally').
`C-x {'
Make selected window narrower (`shrink-window-horizontally').
`C-x -'
Shrink this window if its buffer doesn't need so many lines
(`shrink-window-if-larger-than-buffer').
`C-x +'
Make all windows the same height (`balance-windows').
`Drag-Mouse-1'
Dragging a window's mode line up or down with `Mouse-1' changes
window heights.
`Mouse-2'
`Mouse-2' in a window's mode line deletes all other windows in the
frame (`mouse-delete-other-windows').
`Mouse-3'
`Mouse-3' in a window's mode line deletes that window
(`mouse-delete-window').
To delete a window, type `C-x 0' (`delete-window'). (That is a
zero.) The space occupied by the deleted window is given to an
adjacent window (but not the minibuffer window, even if that is active
at the time). Once a window is deleted, its attributes are forgotten;
only restoring a window configuration can bring it back. Deleting the
window has no effect on the buffer it used to display; the buffer
continues to exist, and you can select it in any window with `C-x b'.
`C-x 4 0' (`kill-buffer-and-window') is a stronger command than `C-x
0'; it kills the current buffer and then deletes the selected window.
`C-x 1' (`delete-other-windows') is more powerful in a different
way; it deletes all the windows except the selected one (and the
minibuffer); the selected window expands to use the whole frame except
for the echo area.
You can also delete a window by clicking on its mode line with
`Mouse-2', and delete all the windows in a frame except one window by
clicking on that window's mode line with `Mouse-3'.
The easiest way to adjust window heights is with a mouse. If you
press `Mouse-1' on a mode line, you can drag that mode line up or down,
changing the heights of the windows above and below it.
To readjust the division of space among vertically adjacent windows,
use `C-x ^' (`enlarge-window'). It makes the currently selected window
get one line bigger, or as many lines as is specified with a numeric
argument. With a negative argument, it makes the selected window
smaller. `C-x }' (`enlarge-window-horizontally') makes the selected
window wider by the specified number of columns. `C-x {'
(`shrink-window-horizontally') makes the selected window narrower by
the specified number of columns.
When you make a window bigger, the space comes from one of its
neighbors. If this makes any window too small, it is deleted and its
space is given to an adjacent window. The minimum size is specified by
the variables `window-min-height' and `window-min-width'.
The command `C-x -' (`shrink-window-if-larger-than-buffer') reduces
the height of the selected window, if it is taller than necessary to
show the whole text of the buffer it is displaying. It gives the extra
lines to other windows in the frame.
You can also use `C-x +' (`balance-windows') to even out the heights
of all the windows in the selected frame.
*Note Minibuffer Edit::, for information about the Resize-Minibuffer
mode, which automatically changes the size of the minibuffer window to
fit the text in the minibuffer.
Frames and X Windows
********************
When using the X Window System, you can create multiple windows at
the X level in a single Emacs session. Each X window that belongs to
Emacs displays a "frame" which can contain one or several Emacs windows.
A frame initially contains a single general-purpose Emacs window which
you can subdivide vertically or horizontally into smaller windows. A
frame normally contains its own echo area and minibuffer, but you can
make frames that don't have these--they use the echo area and
minibuffer of another frame.
Editing you do in one frame also affects the other frames. For
instance, if you put text in the kill ring in one frame, you can yank it
in another frame. If you exit Emacs through `C-x C-c' in one frame, it
terminates all the frames. To delete just one frame, use `C-x 5 0'.
To avoid confusion, we reserve the word "window" for the
subdivisions that Emacs implements, and never use it to refer to a
frame.
Emacs compiled for MS-DOS emulates some aspects of the window system
so that you can use many of the features described in this chapter.
*Note MS-DOS Input::, for more information.
Mouse Commands for Editing
==========================
The mouse commands for selecting and copying a region are mostly
compatible with the `xterm' program. You can use the same mouse
commands for copying between Emacs and other X client programs.
If you select a region with any of these mouse commands, and then
immediately afterward type the <DELETE> function key, it deletes the
region that you selected. The <BACKSPACE> function key and the ASCII
character <DEL> do not do this; if you type any other key in between
the mouse command and <DELETE>, it does not do this.
`Mouse-1'
Move point to where you click (`mouse-set-point'). This is
normally the left button.
`Drag-Mouse-1'
Set the region to the text you select by dragging, and copy it to
the kill ring (`mouse-set-region'). You can specify both ends of
the region with this single command.
If you move the mouse off the top or bottom of the window while
dragging, the window scrolls at a steady rate until you move the
mouse back into the window. This way, you can select regions that
don't fit entirely on the screen. The number of lines scrolled
per step depends on how far away from the window edge the mouse
has gone; the variable `mouse-scroll-min-lines' specifies a
minimum step size.
`Mouse-2'
Yank the last killed text, where you click (`mouse-yank-at-click').
This is normally the middle button.
`Mouse-3'
This command, `mouse-save-then-kill', has several functions
depending on where you click and the status of the region.
The most basic case is when you click `Mouse-1' in one place and
then `Mouse-3' in another. This selects the text between those two
positions as the region. It also copies the new region to the kill
ring, so that you can copy it to someplace else.
If you click `Mouse-1' in the text, scroll with the scroll bar, and
then click `Mouse-3', it remembers where point was before scrolling
(where you put it with `Mouse-1'), and uses that position as the
other end of the region. This is so that you can select a region
that doesn't fit entirely on the screen.
More generally, if you do not have a highlighted region, `Mouse-3'
selects the text between point and the click position as the
region. It does this by setting the mark where point was, and
moving point to where you click.
If you have a highlighted region, or if the region was set just
before by dragging button 1, `Mouse-3' adjusts the nearer end of
the region by moving it to where you click. The adjusted region's
text also replaces the old region's text in the kill ring.
If you originally specified the region using a double or triple
`Mouse-1', so that the region is defined to consist of entire words
or lines, then adjusting the region with `Mouse-3' also proceeds by
entire words or lines.
If you use `Mouse-3' a second time consecutively, at the same
place, that kills the region already selected.
`Double-Mouse-1'
This key sets the region around the word which you click on. If
you click on a character with "symbol" syntax (such as underscore,
in C mode), it sets the region around the symbol surrounding that
character.
If you click on a character with open-parenthesis or
close-parenthesis syntax, it sets the region around the
parenthetical grouping (sexp) which that character starts or ends.
If you click on a character with string-delimiter syntax (such as
a singlequote or doublequote in C), it sets the region around the
string constant (using heuristics to figure out whether that
character is the beginning or the end of it).
`Double-Drag-Mouse-1'
This key selects a region made up of the words you drag across.
`Triple-Mouse-1'
This key sets the region around the line you click on.
`Triple-Drag-Mouse-1'
This key selects a region made up of the lines you drag across.
The simplest way to kill text with the mouse is to press `Mouse-1'
at one end, then press `Mouse-3' twice at the other end. *Note
Killing::. To copy the text into the kill ring without deleting it
from the buffer, press `Mouse-3' just once--or just drag across the
text with `Mouse-1'. Then you can copy it elsewhere by yanking it.
To yank the killed or copied text somewhere else, move the mouse
there and press `Mouse-2'. *Note Yanking::. However, if
`mouse-yank-at-point' is non-`nil', `Mouse-2' yanks at point. Then it
does not matter where you click, or even which of the frame's windows
you click on. The default value is `nil'. This variable also affects
yanking the secondary selection.
To copy text to another X window, kill it or save it in the kill
ring. Under X, this also sets the "primary selection". Then use the
"paste" or "yank" command of the program operating the other window to
insert the text from the selection.
To copy text from another X window, use the "cut" or "copy" command
of the program operating the other window, to select the text you want.
Then yank it in Emacs with `C-y' or `Mouse-2'.
These cutting and pasting commands also work on MS-Windows.
When Emacs puts text into the kill ring, or rotates text to the front
of the kill ring, it sets the "primary selection" in the X server.
This is how other X clients can access the text. Emacs also stores the
text in the cut buffer, but only if the text is short enough
(`x-cut-buffer-max' specifies the maximum number of characters);
putting long strings in the cut buffer can be slow.
The commands to yank the first entry in the kill ring actually check
first for a primary selection in another program; after that, they check
for text in the cut buffer. If neither of those sources provides text
to yank, the kill ring contents are used.
Secondary Selection
===================
The "secondary selection" is another way of selecting text using X.
It does not use point or the mark, so you can use it to kill text
without setting point or the mark.
`M-Drag-Mouse-1'
Set the secondary selection, with one end at the place where you
press down the button, and the other end at the place where you
release it (`mouse-set-secondary'). The highlighting appears and
changes as you drag.
If you move the mouse off the top or bottom of the window while
dragging, the window scrolls at a steady rate until you move the
mouse back into the window. This way, you can mark regions that
don't fit entirely on the screen.
`M-Mouse-1'
Set one endpoint for the "secondary selection"
(`mouse-start-secondary').
`M-Mouse-3'
Make a secondary selection, using the place specified with
`M-Mouse-1' as the other end (`mouse-secondary-save-then-kill').
A second click at the same place kills the secondary selection
just made.
`M-Mouse-2'
Insert the secondary selection where you click
(`mouse-yank-secondary'). This places point at the end of the
yanked text.
Double or triple clicking of `M-Mouse-1' operates on words and
lines, much like `Mouse-1'.
If `mouse-yank-at-point' is non-`nil', `M-Mouse-2' yanks at point.
Then it does not matter precisely where you click; all that matters is
which window you click on. *Note Mouse Commands::.
Following References with the Mouse
===================================
Some Emacs buffers display lists of various sorts. These include
lists of files, of buffers, of possible completions, of matches for a
pattern, and so on.
Since yanking text into these buffers is not very useful, most of
them define `Mouse-2' specially, as a command to use or view the item
you click on.
For example, if you click `Mouse-2' on a file name in a Dired
buffer, you visit that file. If you click `Mouse-2' on an error
message in the `*Compilation*' buffer, you go to the source code for
that error message. If you click `Mouse-2' on a completion in the
`*Completions*' buffer, you choose that completion.
You can usually tell when `Mouse-2' has this special sort of meaning
because the sensitive text highlights when you move the mouse over it.
Mouse Clicks for Menus
======================
Mouse clicks modified with the <CTRL> and <SHIFT> keys bring up
menus.
`C-Mouse-1'
This menu is for selecting a buffer.
`C-Mouse-2'
This menu is for specifying faces and other text properties for
editing formatted text. *Note Formatted Text::.
`C-Mouse-3'
This menu is mode-specific. For most modes, this menu has the same
items as all the mode-specific menu-bar menus put together. Some
modes may specify a different menu for this button.(1)
`S-mouse-1'
This menu is for specifying the frame's principal font.
---------- Footnotes ----------
(1) Some systems use `Mouse-3' for a mode-specific menu. We took a
survey of users, and found they preferred to keep `Mouse-3' for
selecting and killing regions. Hence the decision to use `C-Mouse-3'
for this menu.
Mode Line Mouse Commands
========================
You can use mouse clicks on window mode lines to select and
manipulate windows.
`Mouse-1'
`Mouse-1' on a mode line selects the window above. By dragging
`Mouse-1' on the mode line, you can move it, thus changing the
height of the windows above and below.
`Mouse-2'
`Mouse-2' on a mode line expands that window to fill its frame.
`Mouse-3'
`Mouse-3' on a mode line deletes the window above.
`C-Mouse-2'
`C-Mouse-2' on a mode line splits the window above horizontally,
above the place in the mode line where you click.
`C-Mouse-2' on a scroll bar splits the corresponding window
vertically. *Note Split Window::.
Creating Frames
===============
The prefix key `C-x 5' is analogous to `C-x 4', with parallel
subcommands. The difference is that `C-x 5' commands create a new
frame rather than just a new window in the selected frame (*note Pop Up
Window::.). If an existing visible or iconified frame already displays
the requested material, these commands use the existing frame, after
raising or deiconifying as necessary.
The various `C-x 5' commands differ in how they find or create the
buffer to select:
`C-x 5 2'
Create a new frame (`make-frame-command').
`C-x 5 b BUFNAME <RET>'
Select buffer BUFNAME in another frame. This runs
`switch-to-buffer-other-frame'.
`C-x 5 f FILENAME <RET>'
Visit file FILENAME and select its buffer in another frame. This
runs `find-file-other-frame'. *Note Visiting::.
`C-x 5 d DIRECTORY <RET>'
Select a Dired buffer for directory DIRECTORY in another frame.
This runs `dired-other-frame'. *Note Dired::.
`C-x 5 m'
Start composing a mail message in another frame. This runs
`mail-other-frame'. It is the other-frame variant of `C-x m'.
*Note Sending Mail::.
`C-x 5 .'
Find a tag in the current tag table in another frame. This runs
`find-tag-other-frame', the multiple-frame variant of `M-.'.
*Note Tags::.
`C-x 5 r FILENAME <RET>'
Visit file FILENAME read-only, and select its buffer in another
frame. This runs `find-file-read-only-other-frame'. *Note
Visiting::.
You can control the appearance of new frames you create by setting
the frame parameters in `default-frame-alist'. You can use the
variable `initial-frame-alist' to specify parameters that affect only
the initial frame. *Note Initial Parameters: (elisp)Initial
Parameters, for more information.
The easiest way to specify the principal font for all your Emacs
frames is with an X resource (*note Font X::.), but you can also do it
by modifying `default-frame-alist' to specify the `font' parameter, as
shown here:
(add-to-list 'default-frame-alist '(font . "10x20"))
Making and Using a Speedbar Frame
=================================
An Emacs frame can have a "speedbar", which is a vertical window
that serves as a scrollable menu of files you could visit and tags
within those files. To create a speedbar, type `M-x speedbar'; this
creates a speedbar window for the selected frame. From then on, you can
click on a file name in the speedbar to visit that file in the
corresponding Emacs frame, or click on a tag name to jump to that tag in
the Emacs frame.
Initially the speedbar lists the immediate contents of the current
directory, one file per line. Each line also has a box, `[+]' or
`<+>', that you can click on with `Mouse-2' to "open up" the contents
of that item. If the line names a directory, opening it adds the
contents of that directory to the speedbar display, underneath the
directory's own line. If the line lists an ordinary file, opening it up
adds a list of the tags in that file to the speedbar display. When a
file is opened up, the `[+]' changes to `[-]'; you can click on that
box to "close up" that file (hide its contents).
Some major modes, including Rmail mode, Info, and GUD, have
specialized ways of putting useful items into the speedbar for you to
select. For example, in Rmail mode, the speedbar shows a list of Rmail
files, and lets you move the current message to another Rmail file by
clicking on its `<M>' box.
A speedbar belongs to one Emacs frame, and always operates on that
frame. If you use multiple frames, you can make a speedbar for some or
all of the frames; type `M-x speedbar' in any given frame to make a
speedbar for it.
Multiple Displays
=================
A single Emacs can talk to more than one X Windows display.
Initially, Emacs uses just one display--the one specified with the
`DISPLAY' environment variable or with the `--display' option (*note
Initial Options::.). To connect to another display, use the command
`make-frame-on-display':
`M-x make-frame-on-display <RET> DISPLAY <RET>'
Create a new frame on display DISPLAY.
A single X server can handle more than one screen. When you open
frames on two screens belonging to one server, Emacs knows they share a
single keyboard, and it treats all the commands arriving from these
screens as a single stream of input.
When you open frames on different X servers, Emacs makes a separate
input stream for each server. This way, two users can type
simultaneously on the two displays, and Emacs will not garble their
input. Each server also has its own selected frame. The commands you
enter with a particular X server apply to that server's selected frame.
Despite these features, people using the same Emacs job from
different displays can still interfere with each other if they are not
careful. For example, if any one types `C-x C-c', that exits the Emacs
job for all of them!
Special Buffer Frames
=====================
You can make certain chosen buffers, for which Emacs normally creates
a second window when you have just one window, appear in special frames
of their own. To do this, set the variable
`special-display-buffer-names' to a list of buffer names; any buffer
whose name is in that list automatically gets a special frame, when an
Emacs command wants to display it "in another window."
For example, if you set the variable this way,
(setq special-display-buffer-names
'("*Completions*" "*grep*" "*tex-shell*"))
then completion lists, `grep' output and the TeX mode shell buffer get
individual frames of their own. These frames, and the windows in them,
are never automatically split or reused for any other buffers. They
continue to show the buffers they were created for, unless you alter
them by hand. Killing the special buffer deletes its frame
automatically.
More generally, you can set `special-display-regexps' to a list of
regular expressions; then a buffer gets its own frame if its name
matches any of those regular expressions. (Once again, this applies
only to buffers that normally get displayed for you in a separate
window.)
The variable `special-display-frame-alist' specifies the frame
parameters for these frames. It has a default value, so you don't need
to set it.
For those who know Lisp, an element of
`special-display-buffer-names' or `special-display-regexps' can also be
a list. Then the first element is the buffer name or regular
expression; the rest of the list specifies how to create the frame. It
can be an association list specifying frame parameter values; these
values take precedence over parameter values specified in
`special-display-frame-alist'. Alternatively, it can have this form:
(FUNCTION ARGS...)
where FUNCTION is a symbol. Then the frame is constructed by calling
FUNCTION; its first argument is the buffer, and its remaining arguments
are ARGS.
An analogous feature lets you specify buffers which should be
displayed in the selected window. *Note Force Same Window::. The
same-window feature takes precedence over the special-frame feature;
therefore, if you add a buffer name to `special-display-buffer-names'
and it has no effect, check to see whether that feature is also in use
for the same buffer name.
Setting Frame Parameters
========================
This section describes commands for altering the display style and
window management behavior of the selected frame.
`M-x set-foreground-color <RET> COLOR <RET>'
Specify color COLOR for the foreground of the selected frame.
`M-x set-background-color <RET> COLOR <RET>'
Specify color COLOR for the background of the selected frame.
This changes the foreground color of the `modeline' face also, so
that it remains in inverse video compared with the default.
`M-x set-cursor-color <RET> COLOR <RET>'
Specify color COLOR for the cursor of the selected frame.
`M-x set-mouse-color <RET> COLOR <RET>'
Specify color COLOR for the mouse cursor when it is over the
selected frame.
`M-x set-border-color <RET> COLOR <RET>'
Specify color COLOR for the border of the selected frame.
`M-x list-colors-display'
Display the defined color names and show what the colors look like.
This command is somewhat slow.
`M-x auto-raise-mode'
Toggle whether or not the selected frame should auto-raise.
Auto-raise means that every time you move the mouse onto the
frame, it raises the frame.
Note that this auto-raise feature is implemented by Emacs itself.
Some window managers also implement auto-raise. If you enable
auto-raise for Emacs frames in your X window manager, it should
work, but it is beyond Emacs's control and therefore
`auto-raise-mode' has no effect on it.
`M-x auto-lower-mode'
Toggle whether or not the selected frame should auto-lower.
Auto-lower means that every time you move the mouse off the frame,
the frame moves to the bottom of the stack of X windows.
The command `auto-lower-mode' has no effect on auto-lower
implemented by the X window manager. To control that, you must use
the appropriate window manager features.
`M-x set-frame-font <RET> FONT <RET>'
Specify font FONT as the principal font for the selected frame.
The principal font is used for all text displayed in the frame,
except when a face (*note Faces::.) specifies a different font to
use for certain text. *Note Font X::, for ways to list the
available fonts on your system.
You can also set a frame's principal font through a pop-up menu.
Press `S-Mouse-1' to activate this menu.
In Emacs versions that use an X toolkit, the color-setting and
font-setting functions don't affect menus and the menu bar, since they
are displayed by their own widget classes. To change the appearance of
the menus and menu bar, you must use X resources (*note Resources X::.).
*Note Colors X::, regarding colors. *Note Font X::, regarding choice of
font.
For information on frame parameters and customization, see *Note
Frame Parameters: (elisp)Frame Parameters.
Scroll Bars
===========
When using X, Emacs normally makes a "scroll bar" at the left of
each Emacs window. The scroll bar runs the height of the window, and
shows a moving rectangular inner box which represents the portion of the
buffer currently displayed. The entire height of the scroll bar
represents the entire length of the buffer.
You can use `Mouse-2' (normally, the middle button) in the scroll
bar to move or drag the inner box up and down. If you move it to the
top of the scroll bar, you see the top of the buffer. If you move it to
the bottom of the scroll bar, you see the bottom of the buffer.
The left and right buttons in the scroll bar scroll by controlled
increments. `Mouse-1' (normally, the left button) moves the line at
the level where you click up to the top of the window. `Mouse-3'
(normally, the right button) moves the line at the top of the window
down to the level where you click. By clicking repeatedly in the same
place, you can scroll by the same distance over and over.
Aside from scrolling, you can also click `C-Mouse-2' in the scroll
bar to split a window vertically. The split occurs on the line where
you click.
You can enable or disable Scroll Bar mode with the command `M-x
scroll-bar-mode'. With no argument, it toggles the use of scroll bars.
With an argument, it turns use of scroll bars on if and only if the
argument is positive. This command applies to all frames, including
frames yet to be created. You can use the X resource
`verticalScrollBars' to control the initial setting of Scroll Bar mode.
*Note Resources X::.
To enable or disable scroll bars for just the selected frame, use the
`M-x toggle-scroll-bar' command.
Menu Bars
=========
You can turn display of menu bars on or off with `M-x
menu-bar-mode'. With no argument, this command toggles Menu Bar mode, a
minor mode. With an argument, the command turns Menu Bar mode on if the
argument is positive, off if the argument is not positive. You can use
the X resource `menuBarLines' to control the initial setting of Menu
Bar mode. *Note Resources X::. Expert users often turn off the menu
bar, especially on text-only terminals, where this makes one additional
line available for text.
*Note Menu Bar::, for information on how to invoke commands with the
menu bar.
Using Multiple Typefaces
========================
When using Emacs with X, you can set up multiple styles of displaying
characters. The aspects of style that you can control are the type
font, the foreground color, the background color, and whether to
underline. Emacs on MS-DOS supports faces partially by letting you
control the foreground and background colors of each face (*note
MS-DOS::.).
The way you control display style is by defining named "faces".
Each face can specify a type font, a foreground color, a background
color, and an underline flag; but it does not have to specify all of
them. Then by specifying the face or faces to use for a given part of
the text in the buffer, you control how that text appears.
The style of display used for a given character in the text is
determined by combining several faces. Any aspect of the display style
that isn't specified by overlays or text properties comes from the frame
itself.
Enriched mode, the mode for editing formatted text, includes several
commands and menus for specifying faces. *Note Format Faces::, for how
to specify the font for text in the buffer. *Note Format Colors::, for
how to specify the foreground and background color.
To alter the appearance of a face, use the customization buffer.
*Note Face Customization::. You can also use X resources to specify
attributes of particular faces (*note Resources X::.).
To see what faces are currently defined, and what they look like,
type `M-x list-faces-display'. It's possible for a given face to look
different in different frames; this command shows the appearance in the
frame in which you type it. Here's a list of the standardly defined
faces:
`default'
This face is used for ordinary text that doesn't specify any other
face.
`modeline'
This face is used for mode lines. By default, it's set up as the
inverse of the default face. *Note Display Vars::.
`highlight'
This face is used for highlighting portions of text, in various
modes.
`region'
This face is used for displaying a selected region (when Transient
Mark mode is enabled--see below).
`secondary-selection'
This face is used for displaying a secondary selection (*note
Secondary Selection::.).
`bold'
This face uses a bold variant of the default font, if it has one.
`italic'
This face uses an italic variant of the default font, if it has
one.
`bold-italic'
This face uses a bold italic variant of the default font, if it
has one.
`underline'
This face underlines text.
When Transient Mark mode is enabled, the text of the region is
highlighted when the mark is active. This uses the face named
`region'; you can control the style of highlighting by changing the
style of this face (*note Face Customization::.). *Note Transient
Mark::, for more information about Transient Mark mode and activation
and deactivation of the mark.
One easy way to use faces is to turn on Font Lock mode. This minor
mode, which is always local to a particular buffer, arranges to choose
faces according to the syntax of the text you are editing. It can
recognize comments and strings in most languages; in several languages,
it can also recognize and properly highlight various other important
constructs. *Note Font Lock::, for more information about Font Lock
mode and syntactic highlighting.
You can print out the buffer with the highlighting that appears on
your screen using the command `ps-print-buffer-with-faces'. *Note
Postscript::.
Font Lock mode
==============
Font Lock mode is a minor mode, always local to a particular buffer,
which highlights (or "fontifies") using various faces according to the
syntax of the text you are editing. It can recognize comments and
strings in most languages; in several languages, it can also recognize
and properly highlight various other important constructs--for example,
names of functions being defined or reserved keywords.
The command `M-x font-lock-mode' turns Font Lock mode on or off
according to the argument, and toggles the mode when it has no argument.
The function `turn-on-font-lock' unconditionally enables Font Lock
mode. This is useful in mode-hook functions. For example, to enable
Font Lock mode whenever you edit a C file, you can do this:
(add-hook 'c-mode-hook 'turn-on-font-lock)
To turn on Font Lock mode automatically in all modes which support
it, use the function `global-font-lock-mode', like this:
(global-font-lock-mode 1)
In Font Lock mode, when you edit the text, the highlighting updates
automatically in the line that you changed. Most changes don't affect
the highlighting of subsequent lines, but occasionally they do. To
rehighlight a range of lines, use the command `M-g M-g'
(`font-lock-fontify-block').
In certain major modes, `M-g M-g' refontifies the entire current
function. (The variable `font-lock-mark-block-function' controls how
to find the current function.) In other major modes, `M-g M-g'
refontifies 16 lines above and below point.
With a prefix argument N, `M-g M-g' refontifies N lines above and
below point, regardless of the mode.
To get the full benefit of Font Lock mode, you need to choose a
default font which has bold, italic, and bold-italic variants; or else
you need to have a color or gray-scale screen.
The variable `font-lock-maximum-decoration' specifies the preferred
level of fontification, for modes that provide multiple levels. Level
1 is the least amount of fontification; some modes support levels as
high as 3. The normal default is "as high as possible." You can
specify an integer, which applies to all modes, or you can specify
different numbers for particular major modes; for example, to use level
1 for C/C++ modes, and the default level otherwise, use this:
(setq font-lock-maximum-decoration
'((c-mode . 1) (c++-mode . 1)))
Fontification can be too slow for large buffers, so you can suppress
it. The variable `font-lock-maximum-size' specifies a buffer size,
beyond which buffer fontification is suppressed.
Comment and string fontification (or "syntactic" fontification)
relies on analysis of the syntactic structure of the buffer text. For
the purposes of speed, some modes including C mode and Lisp mode rely on
a special convention: an open-parenthesis in the leftmost column always
defines the beginning of a defun, and is thus always outside any string
or comment. (*Note Defuns::.) If you don't follow this convention,
then Font Lock mode can misfontify the text after an open-parenthesis in
the leftmost column that is inside a string or comment.
The variable `font-lock-beginning-of-syntax-function' (always
buffer-local) specifies how Font Lock mode can find a position
guaranteed to be outside any comment or string. In modes which use the
leftmost column parenthesis convention, the default value of the
variable is `beginning-of-defun'--that tells Font Lock mode to use the
convention. If you set this variable to `nil', Font Lock no longer
relies on the convention. This avoids incorrect results, but the price
is that, in some cases, fontification for a changed text must rescan
buffer text from the beginning of the buffer.
Font Lock highlighting patterns already exist for many modes, but you
may want to fontify additional patterns. You can use the function
`font-lock-add-keywords', to add your own highlighting patterns for a
particular mode. For example, to highlight `FIXME:' words in C
comments, use this:
(font-lock-add-keywords
'c-mode
'(("\\<\\(FIXME\\):" 1 font-lock-warning-face t)))
Font Lock Support Modes
=======================
Font Lock support modes make Font Lock mode faster for large buffers.
There are two support modes: Fast Lock mode and Lazy Lock mode. They
use two different methods of speeding up Font Lock mode.
Fast Lock Mode
--------------
To make Font Lock mode faster for buffers visiting large files, you
can use Fast Lock mode. Fast Lock mode saves the font information for
each file in a separate cache file; each time you visit the file, it
rereads the font information from the cache file instead of refontifying
the text from scratch.
The command `M-x fast-lock-mode' turns Fast Lock mode on or off,
according to the argument (with no argument, it toggles). You can also
arrange to enable Fast Lock mode whenever you use Font Lock mode, like
this:
(setq font-lock-support-mode 'fast-lock-mode)
It is not worth writing a cache file for small buffers. Therefore,
the variable `fast-lock-minimum-size' specifies a minimum file size for
caching font information.
The variable `fast-lock-cache-directories' specifies where to put
the cache files. Its value is a list of directories to try; `"."'
means the same directory as the file being edited. The default value is
`("." "~/.emacs-flc")', which means to use the same directory if
possible, and otherwise the directory `~/.emacs-flc'.
The variable `fast-lock-save-others' specifies whether Fast Lock
mode should save cache files for files that you do not own. A
non-`nil' value means yes (and that is the default).
Lazy Lock Mode
--------------
To make Font Lock mode faster for large buffers, you can use Lazy
Lock mode to reduce the amount of text that is fontified. In Lazy Lock
mode, buffer fontification is demand-driven; it happens to portions of
the buffer that are about to be displayed. And fontification of your
changes is deferred; it happens only when Emacs has been idle for a
certain short period of time.
The command `M-x lazy-lock-mode' turns Lazy Lock mode on or off,
according to the argument (with no argument, it toggles). You can also
arrange to enable Lazy Lock mode whenever you use Font Lock mode, like
this:
(setq font-lock-support-mode 'lazy-lock-mode)
It is not worth avoiding buffer fontification for small buffers.
Therefore, the variable `lazy-lock-minimum-size' specifies a minimum
buffer size for demand-driven buffer fontification. Buffers smaller
than that are fontified all at once, as in plain Font Lock mode.
When you alter the buffer, Lazy Lock mode defers fontification of the
text you changed. The variable `lazy-lock-defer-time' specifies how
many seconds Emacs must be idle before it starts fontifying your
changes. If the value is 0, then changes are fontified immediately, as
in plain Font Lock mode.
Lazy Lock mode normally fontifies newly visible portions of the
buffer before they are first displayed. However, if the value of
`lazy-lock-defer-on-scrolling' is non-`nil', newly visible text is
fontified only when Emacs is idle for `lazy-lock-defer-time' seconds.
In some modes, including C mode and Emacs Lisp mode, changes in one
line's contents can alter the context for subsequent lines, and thus
change how they ought to be fontified. Ordinarily, you must type `M-g
M-g' to refontify the subsequent lines. However, if you set the
variable `lazy-lock-defer-contextually' to non-`nil', Lazy Lock mode
does this automatically, after `lazy-lock-defer-time' seconds.
When Emacs is idle for a long time, Lazy Lock fontifies additional
portions of the buffer, not yet displayed, in case you will display them
later. This is called "stealth fontification".
The variable `lazy-lock-stealth-time' specifies how many seconds
Emacs has to be idle before stealth fontification starts. A value of
`nil' means no stealth fontification. The variables
`lazy-lock-stealth-lines' and `lazy-lock-stealth-verbose' specify the
granularity and verbosity of stealth fontification.
Fast Lock or Lazy Lock?
-----------------------
Here is a simple guide to help you choose one of the Font Lock
support modes.
* Fast Lock mode intervenes only during file visiting and buffer
killing (and related events); therefore buffer editing and window
scrolling are no faster or slower than in plain Font Lock mode.
* Fast Lock mode is slower at reading a cache file than Lazy Lock
mode is at fontifying a window; therefore Fast Lock mode is slower
at visiting a file than Lazy Lock mode.
* Lazy Lock mode intervenes during window scrolling to fontify text
that scrolls onto the screen; therefore, scrolling is slower than
in plain Font Lock mode.
* Lazy Lock mode doesn't fontify during buffer editing (it defers
fontification of changes); therefore, editing is faster than in
plain Font Lock mode.
* Fast Lock mode can be fooled by a file that is kept under version
control software; therefore buffer fontification may occur even
when a cache file exists for the file.
* Fast Lock mode only works with a buffer visiting a file; Lazy Lock
mode works with any buffer.
* Fast Lock mode generates cache files; Lazy Lock mode does not.
The variable `font-lock-support-mode' specifies which of these
support modes to use; for example, to specify that Fast Lock mode is
used for C/C++ modes, and Lazy Lock mode otherwise, set the variable
like this:
(setq font-lock-support-mode
'((c-mode . fast-lock-mode) (c++-mode . fast-lock-mode)
(t . lazy-lock-mode)))
Highlight Changes Mode
======================
Use `M-x highlight-changes-mode' to enable a minor mode that uses
faces (colors, typically) to indicate which parts of the buffer were
changed most recently.
Miscellaneous X Window Features
===============================
The following commands let you create, delete and operate on frames:
`C-z'
Iconify the selected Emacs frame (`iconify-or-deiconify-frame').
The normal meaning of `C-z', to suspend Emacs, is not useful under
a window system, so it has a different binding in that case.
If you type this command on an Emacs frame's icon, it deiconifies
the frame.
`C-x 5 0'
Delete the selected frame (`delete-frame'). This is not allowed if
there is only one frame.
`C-x 5 o'
Select another frame, raise it, and warp the mouse to it so that it
stays selected. If you repeat this command, it cycles through all
the frames on your terminal.
Non-Window Terminals
====================
If your terminal does not have a window system that Emacs supports,
then it can display only one Emacs frame at a time. However, you can
still create multiple Emacs frames, and switch between them. Switching
frames on these terminals is much like switching between different
window configurations.
Use `C-x 5 2' to create a new frame and switch to it; use `C-x 5 o'
to cycle through the existing frames; use `C-x 5 0' to delete the
current frame.
Each frame has a number to distinguish it. If your terminal can
display only one frame at a time, the selected frame's number N appears
near the beginning of the mode line, in the form `FN'.
`FN' is actually the frame's name. You can also specify a different
name if you wish, and you can select a frame by its name. Use the
command `M-x set-frame-name <RET> NAME <RET>' to specify a new name for
the selected frame, and use `M-x select-frame-by-name <RET> NAME <RET>'
to select a frame according to its name. The name you specify appears
in the mode line when the frame is selected.
International Character Set Support
***********************************
Emacs supports a wide variety of international character sets,
including European variants of the Latin alphabet, as well as Chinese,
Devanagari (Hindi and Marathi), Ethiopian, Greek, IPA, Japanese, Korean,
Lao, Russian, Thai, Tibetan, and Vietnamese scripts. These features
have been merged from the modified version of Emacs known as MULE (for
"MULti-lingual Enhancement to GNU Emacs")
Introduction to International Character Sets
============================================
The users of these scripts have established many more-or-less
standard coding systems for storing files. Emacs internally uses a
single multibyte character encoding, so that it can intermix characters
from all these scripts in a single buffer or string. This encoding
represents each non-ASCII character as a sequence of bytes in the range
0200 through 0377. Emacs translates between the multibyte character
encoding and various other coding systems when reading and writing
files, when exchanging data with subprocesses, and (in some cases) in
the `C-q' command (*note Multibyte Conversion::.).
The command `C-h h' (`view-hello-file') displays the file
`etc/HELLO', which shows how to say "hello" in many languages. This
illustrates various scripts.
Keyboards, even in the countries where these character sets are used,
generally don't have keys for all the characters in them. So Emacs
supports various "input methods", typically one for each script or
language, to make it convenient to type them.
The prefix key `C-x <RET>' is used for commands that pertain to
multibyte characters, coding systems, and input methods.
Enabling Multibyte Characters
=============================
You can enable or disable multibyte character support, either for
Emacs as a whole, or for a single buffer. When multibyte characters are
disabled in a buffer, then each byte in that buffer represents a
character, even codes 0200 through 0377. The old features for
supporting the European character sets, ISO Latin-1 and ISO Latin-2,
work as they did in Emacs 19 and also work for the other ISO 8859
character sets.
However, there is no need to turn off multibyte character support to
use ISO Latin; the Emacs multibyte character set includes all the
characters in these character sets, and Emacs can translate
automatically to and from the ISO codes.
To edit a particular file in unibyte representation, visit it using
`find-file-literally'. *Note Visiting::. To convert a buffer in
multibyte representation into a single-byte representation of the same
characters, the easiest way is to save the contents in a file, kill the
buffer, and find the file again with `find-file-literally'. You can
also use `C-x <RET> c' (`universal-coding-system-argument') and specify
`raw-text' as the coding system with which to find or save a file.
*Note Specify Coding::. Finding a file as `raw-text' doesn't disable
format conversion, uncompression and auto mode selection as
`find-file-literally' does.
To turn off multibyte character support by default, start Emacs with
the `--unibyte' option (*note Initial Options::.), or set the
environment variable `EMACS_UNIBYTE'. You can also customize
`enable-multibyte-characters' or, equivalently, directly set the
variable `default-enable-multibyte-characters' in your init file to
have basically the same effect as `--unibyte'.
Multibyte strings are not created during initialization from the
values of environment variables, `/etc/passwd' entries etc. that
contain non-ASCII 8-bit characters. However, the initialization file is
normally read as multibyte--like Lisp files in general--even with
`--unibyte'. To avoid multibyte strings being generated by non-ASCII
characters in it, put `-*-unibyte: t;-*-' in a comment on the first
line. Do the same for initialization files for packages like Gnus.
The mode line indicates whether multibyte character support is
enabled in the current buffer. If it is, there are two or more
characters (most often two dashes) before the colon near the beginning
of the mode line. When multibyte characters are not enabled, just one
dash precedes the colon.
Language Environments
=====================
All supported character sets are supported in Emacs buffers whenever
multibyte characters are enabled; there is no need to select a
particular language in order to display its characters in an Emacs
buffer. However, it is important to select a "language environment" in
order to set various defaults. The language environment really
represents a choice of preferred script (more or less) rather than a
choice of language.
The language environment controls which coding systems to recognize
when reading text (*note Recognize Coding::.). This applies to files,
incoming mail, netnews, and any other text you read into Emacs. It may
also specify the default coding system to use when you create a file.
Each language environment also specifies a default input method.
The way to select a language environment is with the command `M-x
set-language-environment'. It makes no difference which buffer is
current when you use this command, because the effects apply globally to
the Emacs session. The supported language environments include:
Chinese-BIG5, Chinese-CNS, Chinese-GB, Cyrillic-Alternativnyj,
Cyrillic-ISO, Cyrillic-KOI8, Devanagari, English, Ethiopic, Greek,
Hebrew, Japanese, Korean, Lao, Latin-1, Latin-2, Latin-3, Latin-4,
Latin-5, Thai, Tibetan, and Vietnamese.
Some operating systems let you specify the language you are using by
setting locale environment variables. Emacs handles one common special
case of this: if your locale name for character types contains the
string `8859-N', Emacs automatically selects the corresponding language
environment.
To display information about the effects of a certain language
environment LANG-ENV, use the command `C-h L LANG-ENV <RET>'
(`describe-language-environment'). This tells you which languages this
language environment is useful for, and lists the character sets,
coding systems, and input methods that go with it. It also shows some
sample text to illustrate scripts used in this language environment.
By default, this command describes the chosen language environment.
You can customize any language environment with the normal hook
`set-language-environment-hook'. The command
`set-language-environment' runs that hook after setting up the new
language environment. The hook functions can test for a specific
language environment by checking the variable
`current-language-environment'.
Before it starts to set up the new language environment,
`set-language-environment' first runs the hook
`exit-language-environment-hook'. This hook is useful for undoing
customizations that were made with `set-language-environment-hook'.
For instance, if you set up a special key binding in a specific language
environment using `set-language-environment-hook', you should set up
`exit-language-environment-hook' to restore the normal binding for that
key.
Input Methods
=============
An "input method" is a kind of character conversion designed
specifically for interactive input. In Emacs, typically each language
has its own input method; sometimes several languages which use the same
characters can share one input method. A few languages support several
input methods.
The simplest kind of input method works by mapping ASCII letters into
another alphabet. This is how the Greek and Russian input methods work.
A more powerful technique is composition: converting sequences of
characters into one letter. Many European input methods use composition
to produce a single non-ASCII letter from a sequence that consists of a
letter followed by accent characters (or vice versa). For example, some
methods convert the sequence `a'' into a single accented letter. These
input methods have no special commands of their own; all they do is
compose sequences of printing characters.
The input methods for syllabic scripts typically use mapping followed
by composition. The input methods for Thai and Korean work this way.
First, letters are mapped into symbols for particular sounds or tone
marks; then, sequences of these which make up a whole syllable are
mapped into one syllable sign.
Chinese and Japanese require more complex methods. In Chinese input
methods, first you enter the phonetic spelling of a Chinese word (in
input method `chinese-py', among others), or a sequence of portions of
the character (input methods `chinese-4corner' and `chinese-sw', and
others). Since one phonetic spelling typically corresponds to many
different Chinese characters, you must select one of the alternatives
using special Emacs commands. Keys such as `C-f', `C-b', `C-n', `C-p',
and digits have special definitions in this situation, used for
selecting among the alternatives. <TAB> displays a buffer showing all
the possibilities.
In Japanese input methods, first you input a whole word using
phonetic spelling; then, after the word is in the buffer, Emacs converts
it into one or more characters using a large dictionary. One phonetic
spelling corresponds to many differently written Japanese words, so you
must select one of them; use `C-n' and `C-p' to cycle through the
alternatives.
Sometimes it is useful to cut off input method processing so that the
characters you have just entered will not combine with subsequent
characters. For example, in input method `latin-1-postfix', the
sequence `e '' combines to form an `e' with an accent. What if you
want to enter them as separate characters?
One way is to type the accent twice; that is a special feature for
entering the separate letter and accent. For example, `e ' '' gives
you the two characters `e''. Another way is to type another letter
after the `e'--something that won't combine with that--and immediately
delete it. For example, you could type `e e <DEL> '' to get separate
`e' and `''.
Another method, more general but not quite as easy to type, is to use
`C-\ C-\' between two characters to stop them from combining. This is
the command `C-\' (`toggle-input-method') used twice. *Note Select
Input Method::.
`C-\ C-\' is especially useful inside an incremental search, because
it stops waiting for more characters to combine, and starts searching
for what you have already entered.
The variables `input-method-highlight-flag' and
`input-method-verbose-flag' control how input methods explain what is
happening. If `input-method-highlight-flag' is non-`nil', the partial
sequence is highlighted in the buffer. If `input-method-verbose-flag'
is non-`nil', the list of possible characters to type next is displayed
in the echo area (but not when you are in the minibuffer).
Selecting an Input Method
=========================
`C-\'
Enable or disable use of the selected input method.
`C-x <RET> C-\ METHOD <RET>'
Select a new input method for the current buffer.
`C-h I METHOD <RET>'
`C-h C-\ METHOD <RET>'
Describe the input method METHOD (`describe-input-method'). By
default, it describes the current input method (if any). This
description should give you the full details of how to use any
particular input method.
`M-x list-input-methods'
Display a list of all the supported input methods.
To choose an input method for the current buffer, use `C-x <RET>
C-\' (`set-input-method'). This command reads the input method name
with the minibuffer; the name normally starts with the language
environment that it is meant to be used with. The variable
`current-input-method' records which input method is selected.
Input methods use various sequences of ASCII characters to stand for
non-ASCII characters. Sometimes it is useful to turn off the input
method temporarily. To do this, type `C-\' (`toggle-input-method').
To reenable the input method, type `C-\' again.
If you type `C-\' and you have not yet selected an input method, it
prompts for you to specify one. This has the same effect as using `C-x
<RET> C-\' to specify an input method.
Selecting a language environment specifies a default input method for
use in various buffers. When you have a default input method, you can
select it in the current buffer by typing `C-\'. The variable
`default-input-method' specifies the default input method (`nil' means
there is none).
Some input methods for alphabetic scripts work by (in effect)
remapping the keyboard to emulate various keyboard layouts commonly used
for those scripts. How to do this remapping properly depends on your
actual keyboard layout. To specify which layout your keyboard has, use
the command `M-x quail-set-keyboard-layout'.
To display a list of all the supported input methods, type `M-x
list-input-methods'. The list gives information about each input
method, including the string that stands for it in the mode line.
Unibyte and Multibyte Non-ASCII characters
==========================================
When multibyte characters are enabled, character codes 0240 (octal)
through 0377 (octal) are not really legitimate in the buffer. The valid
non-ASCII printing characters have codes that start from 0400.
If you type a self-inserting character in the invalid range 0240
through 0377, Emacs assumes you intended to use one of the ISO Latin-N
character sets, and converts it to the Emacs code representing that
Latin-N character. You select *which* ISO Latin character set to use
through your choice of language environment (*note Language
Environments::.). If you do not specify a choice, the default is
Latin-1.
The same thing happens when you use `C-q' to enter an octal code in
this range.
Coding Systems
==============
Users of various languages have established many more-or-less
standard coding systems for representing them. Emacs does not use
these coding systems internally; instead, it converts from various
coding systems to its own system when reading data, and converts the
internal coding system to other coding systems when writing data.
Conversion is possible in reading or writing files, in sending or
receiving from the terminal, and in exchanging data with subprocesses.
Emacs assigns a name to each coding system. Most coding systems are
used for one language, and the name of the coding system starts with the
language name. Some coding systems are used for several languages;
their names usually start with `iso'. There are also special coding
systems `no-conversion', `raw-text' and `emacs-mule' which do not
convert printing characters at all.
In addition to converting various representations of non-ASCII
characters, a coding system can perform end-of-line conversion. Emacs
handles three different conventions for how to separate lines in a file:
newline, carriage-return linefeed, and just carriage-return.
`C-h C CODING <RET>'
Describe coding system CODING.
`C-h C <RET>'
Describe the coding systems currently in use.
`M-x list-coding-systems'
Display a list of all the supported coding systems.
The command `C-h C' (`describe-coding-system') displays information
about particular coding systems. You can specify a coding system name
as argument; alternatively, with an empty argument, it describes the
coding systems currently selected for various purposes, both in the
current buffer and as the defaults, and the priority list for
recognizing coding systems (*note Recognize Coding::.).
To display a list of all the supported coding systems, type `M-x
list-coding-systems'. The list gives information about each coding
system, including the letter that stands for it in the mode line (*note
Mode Line::.).
Each of the coding systems that appear in this list--except for
`no-conversion', which means no conversion of any kind--specifies how
and whether to convert printing characters, but leaves the choice of
end-of-line conversion to be decided based on the contents of each file.
For example, if the file appears to use the sequence carriage-return
linefeed to separate lines, DOS end-of-line conversion will be used.
Each of the listed coding systems has three variants which specify
exactly what to do for end-of-line conversion:
`...-unix'
Don't do any end-of-line conversion; assume the file uses newline
to separate lines. (This is the convention normally used on Unix
and GNU systems.)
`...-dos'
Assume the file uses carriage-return linefeed to separate lines,
and do the appropriate conversion. (This is the convention
normally used on Microsoft systems.(1))
`...-mac'
Assume the file uses carriage-return to separate lines, and do the
appropriate conversion. (This is the convention normally used on
the Macintosh system.)
These variant coding systems are omitted from the
`list-coding-systems' display for brevity, since they are entirely
predictable. For example, the coding system `iso-latin-1' has variants
`iso-latin-1-unix', `iso-latin-1-dos' and `iso-latin-1-mac'.
The coding system `raw-text' is good for a file which is mainly
ASCII text, but may contain byte values above 127 which are not meant to
encode non-ASCII characters. With `raw-text', Emacs copies those byte
values unchanged, and sets `enable-multibyte-characters' to `nil' in
the current buffer so that they will be interpreted properly.
`raw-text' handles end-of-line conversion in the usual way, based on
the data encountered, and has the usual three variants to specify the
kind of end-of-line conversion to use.
In contrast, the coding system `no-conversion' specifies no
character code conversion at all--none for non-ASCII byte values and
none for end of line. This is useful for reading or writing binary
files, tar files, and other files that must be examined verbatim. It,
too, sets `enable-multibyte-characters' to `nil'.
The easiest way to edit a file with no conversion of any kind is with
the `M-x find-file-literally' command. This uses `no-conversion', and
also suppresses other Emacs features that might convert the file
contents before you see them. *Note Visiting::.
The coding system `emacs-mule' means that the file contains
non-ASCII characters stored with the internal Emacs encoding. It
handles end-of-line conversion based on the data encountered, and has
the usual three variants to specify the kind of end-of-line conversion.
---------- Footnotes ----------
(1) It is also specified for MIME `text/*' bodies and in other
network transport contexts. It is different from the SGML reference
syntax record-start/record-end format which Emacs doesn't support
directly.
Recognizing Coding Systems
==========================
Most of the time, Emacs can recognize which coding system to use for
any given file--once you have specified your preferences.
Some coding systems can be recognized or distinguished by which byte
sequences appear in the data. However, there are coding systems that
cannot be distinguished, not even potentially. For example, there is no
way to distinguish between Latin-1 and Latin-2; they use the same byte
values with different meanings.
Emacs handles this situation by means of a priority list of coding
systems. Whenever Emacs reads a file, if you do not specify the coding
system to use, Emacs checks the data against each coding system,
starting with the first in priority and working down the list, until it
finds a coding system that fits the data. Then it converts the file
contents assuming that they are represented in this coding system.
The priority list of coding systems depends on the selected language
environment (*note Language Environments::.). For example, if you use
French, you probably want Emacs to prefer Latin-1 to Latin-2; if you use
Czech, you probably want Latin-2 to be preferred. This is one of the
reasons to specify a language environment.
However, you can alter the priority list in detail with the command
`M-x prefer-coding-system'. This command reads the name of a coding
system from the minibuffer, and adds it to the front of the priority
list, so that it is preferred to all others. If you use this command
several times, each use adds one element to the front of the priority
list.
If you use a coding system that specifies the end-of-line conversion
type, such as `iso-8859-1-dos', what that means is that Emacs should
attempt to recognize `iso-8859-1' with priority, and should use DOS
end-of-line conversion in case it recognizes `iso-8859-1'.
Sometimes a file name indicates which coding system to use for the
file. The variable `file-coding-system-alist' specifies this
correspondence. There is a special function
`modify-coding-system-alist' for adding elements to this list. For
example, to read and write all `.txt' files using the coding system
`china-iso-8bit', you can execute this Lisp expression:
(modify-coding-system-alist 'file "\\.txt\\'" 'china-iso-8bit)
The first argument should be `file', the second argument should be a
regular expression that determines which files this applies to, and the
third argument says which coding system to use for these files.
Emacs recognizes which kind of end-of-line conversion to use based on
the contents of the file: if it sees only carriage-returns, or only
carriage-return linefeed sequences, then it chooses the end-of-line
conversion accordingly. You can inhibit the automatic use of
end-of-line conversion by setting the variable `inhibit-eol-conversion'
to non-`nil'.
You can specify the coding system for a particular file using the
`-*-...-*-' construct at the beginning of a file, or a local variables
list at the end (*note File Variables::.). You do this by defining a
value for the "variable" named `coding'. Emacs does not really have a
variable `coding'; instead of setting a variable, it uses the specified
coding system for the file. For example, `-*-mode: C; coding:
latin-1;-*-' specifies use of the Latin-1 coding system, as well as C
mode. If you specify the coding explicitly in the file, that overrides
`file-coding-system-alist'.
The variable `auto-coding-alist' is the strongest way to specify the
coding system for certain patterns of file names; this variable even
overrides `-*-coding:-*-' tags in the file itself. Emacs uses this
feature for tar and archive files, to prevent Emacs from being confused
by a `-*-coding:-*-' tag in a member of the archive and thinking it
applies to the archive file as a whole.
Once Emacs has chosen a coding system for a buffer, it stores that
coding system in `buffer-file-coding-system' and uses that coding
system, by default, for operations that write from this buffer into a
file. This includes the commands `save-buffer' and `write-region'. If
you want to write files from this buffer using a different coding
system, you can specify a different coding system for the buffer using
`set-buffer-file-coding-system' (*note Specify Coding::.).
When you send a message with Mail mode (*note Sending Mail::.),
Emacs has four different ways to determine the coding system to use for
encoding the message text. It tries the buffer's own value of
`buffer-file-coding-system', if that is non-`nil'. Otherwise, it uses
the value of `sendmail-coding-system', if that is non-`nil'. The third
way is to use the default coding system for new files, which is
controlled by your choice of language environment, if that is
non-`nil'. If all of these three values are `nil', Emacs encodes
outgoing mail using the Latin-1 coding system.
When you get new mail in Rmail, each message is translated
automatically from the coding system it is written in--as if it were a
separate file. This uses the priority list of coding systems that you
have specified. If a MIME message specifies a character set, Rmail
obeys that specification, unless `rmail-decode-mime-charset' is `nil'.
For reading and saving Rmail files themselves, Emacs uses the coding
system specified by the variable `rmail-file-coding-system'. The
default value is `nil', which means that Rmail files are not translated
(they are read and written in the Emacs internal character code).
Specifying a Coding System
==========================
In cases where Emacs does not automatically choose the right coding
system, you can use these commands to specify one:
`C-x <RET> f CODING <RET>'
Use coding system CODING for the visited file in the current
buffer.
`C-x <RET> c CODING <RET>'
Specify coding system CODING for the immediately following command.
`C-x <RET> k CODING <RET>'
Use coding system CODING for keyboard input.
`C-x <RET> t CODING <RET>'
Use coding system CODING for terminal output.
`C-x <RET> p INPUT-CODING <RET> OUTPUT-CODING <RET>'
Use coding systems INPUT-CODING and OUTPUT-CODING for subprocess
input and output in the current buffer.
`C-x <RET> x CODING <RET>'
Use coding system CODING for transferring selections to and from
other programs through the window system.
`C-x <RET> X CODING <RET>'
Use coding system CODING for transferring *one* selection--the
next one--to or from the window system.
The command `C-x <RET> f' (`set-buffer-file-coding-system')
specifies the file coding system for the current buffer--in other
words, which coding system to use when saving or rereading the visited
file. You specify which coding system using the minibuffer. Since this
command applies to a file you have already visited, it affects only the
way the file is saved.
Another way to specify the coding system for a file is when you visit
the file. First use the command `C-x <RET> c'
(`universal-coding-system-argument'); this command uses the minibuffer
to read a coding system name. After you exit the minibuffer, the
specified coding system is used for *the immediately following command*.
So if the immediately following command is `C-x C-f', for example,
it reads the file using that coding system (and records the coding
system for when the file is saved). Or if the immediately following
command is `C-x C-w', it writes the file using that coding system.
Other file commands affected by a specified coding system include `C-x
C-i' and `C-x C-v', as well as the other-window variants of `C-x C-f'.
`C-x <RET> c' also affects commands that start subprocesses,
including `M-x shell' (*note Shell::.).
However, if the immediately following command does not use the coding
system, then `C-x <RET> c' ultimately has no effect.
An easy way to visit a file with no conversion is with the `M-x
find-file-literally' command. *Note Visiting::.
The variable `default-buffer-file-coding-system' specifies the
choice of coding system to use when you create a new file. It applies
when you find a new file, and when you create a buffer and then save it
in a file. Selecting a language environment typically sets this
variable to a good choice of default coding system for that language
environment.
The command `C-x <RET> t' (`set-terminal-coding-system') specifies
the coding system for terminal output. If you specify a character code
for terminal output, all characters output to the terminal are
translated into that coding system.
This feature is useful for certain character-only terminals built to
support specific languages or character sets--for example, European
terminals that support one of the ISO Latin character sets. You need to
specify the terminal coding system when using multibyte text, so that
Emacs knows which characters the terminal can actually handle.
By default, output to the terminal is not translated at all, unless
Emacs can deduce the proper coding system from your terminal type.
The command `C-x <RET> k' (`set-keyboard-coding-system') specifies
the coding system for keyboard input. Character-code translation of
keyboard input is useful for terminals with keys that send non-ASCII
graphic characters--for example, some terminals designed for ISO
Latin-1 or subsets of it.
By default, keyboard input is not translated at all.
There is a similarity between using a coding system translation for
keyboard input, and using an input method: both define sequences of
keyboard input that translate into single characters. However, input
methods are designed to be convenient for interactive use by humans, and
the sequences that are translated are typically sequences of ASCII
printing characters. Coding systems typically translate sequences of
non-graphic characters.
The command `C-x <RET> x' (`set-selection-coding-system') specifies
the coding system for sending selected text to the window system, and
for receiving the text of selections made in other applications. This
command applies to all subsequent selections, until you override it by
using the command again. The command `C-x <RET> X'
(`set-next-selection-coding-system') specifies the coding system for
the next selection made in Emacs or read by Emacs.
The command `C-x <RET> p' (`set-buffer-process-coding-system')
specifies the coding system for input and output to a subprocess. This
command applies to the current buffer; normally, each subprocess has its
own buffer, and thus you can use this command to specify translation to
and from a particular subprocess by giving the command in the
corresponding buffer.
By default, process input and output are not translated at all.
The variable `file-name-coding-system' specifies a coding system to
use for encoding file names. If you set the variable to a coding
system name (as a Lisp symbol or a string), Emacs encodes file names
using that coding system for all file operations. This makes it
possible to use non-ASCII characters in file names--or, at least, those
non-ASCII characters which the specified coding system can encode.
If `file-name-coding-system' is `nil', Emacs uses a default coding
system determined by the selected language environment. In the default
language environment, any non-ASCII characters in file names are not
encoded specially; they appear in the file system using the internal
Emacs representation.
*Warning:* if you change `file-name-coding-system' (or the language
environment) in the middle of an Emacs session, problems can result if
you have already visited files whose names were encoded using the
earlier coding system and cannot be encoded (or are encoded
differently) under the new coding system. If you try to save one of
these buffers under the visited file name, saving may use the wrong file
name, or it may get an error. If such a problem happens, use `C-x C-w'
to specify a new file name for that buffer.
Fontsets
========
A font for X Windows typically defines shapes for one alphabet or
script. Therefore, displaying the entire range of scripts that Emacs
supports requires a collection of many fonts. In Emacs, such a
collection is called a "fontset". A fontset is defined by a list of
fonts, each assigned to handle a range of character codes.
Each fontset has a name, like a font. The available X fonts are
defined by the X server; fontsets, however, are defined within Emacs
itself. Once you have defined a fontset, you can use it within Emacs by
specifying its name, anywhere that you could use a single font. Of
course, Emacs fontsets can use only the fonts that the X server
supports; if certain characters appear on the screen as hollow boxes,
this means that the fontset in use for them has no font for those
characters.
Emacs creates two fontsets automatically: the "standard fontset" and
the "startup fontset". The standard fontset is most likely to have
fonts for a wide variety of non-ASCII characters; however, this is not
the default for Emacs to use. (By default, Emacs tries to find a font
which has bold and italic variants.) You can specify use of the
standard fontset with the `-fn' option, or with the `Font' X resource
(*note Font X::.). For example,
emacs -fn fontset-standard
A fontset does not necessarily specify a font for every character
code. If a fontset specifies no font for a certain character, or if it
specifies a font that does not exist on your system, then it cannot
display that character properly. It will display that character as an
empty box instead.
The fontset height and width are determined by the ASCII characters
(that is, by the font used for ASCII characters in that fontset). If
another font in the fontset has a different height, or a different
width, then characters assigned to that font are clipped to the
fontset's size. If `highlight-wrong-size-font' is non-`nil', a box is
displayed around these wrong-size characters as well.
Defining fontsets
=================
Emacs creates a standard fontset automatically according to the value
of `standard-fontset-spec'. This fontset's name is
-*-fixed-medium-r-normal-*-16-*-*-*-*-*-fontset-standard
or just `fontset-standard' for short.
Bold, italic, and bold-italic variants of the standard fontset are
created automatically. Their names have `bold' instead of `medium', or
`i' instead of `r', or both.
If you specify a default ASCII font with the `Font' resource or the
`-fn' argument, Emacs generates a fontset from it automatically. This
is the "startup fontset" and its name is `fontset-startup'. It does
this by replacing the FOUNDRY, FAMILY, ADD_STYLE, and AVERAGE_WIDTH
fields of the font name with `*', replacing CHARSET_REGISTRY field with
`fontset', and replacing CHARSET_ENCODING field with `startup', then
using the resulting string to specify a fontset.
For instance, if you start Emacs this way,
emacs -fn "*courier-medium-r-normal--14-140-*-iso8859-1"
Emacs generates the following fontset and uses it for the initial X
window frame:
-*-*-medium-r-normal-*-14-140-*-*-*-*-fontset-startup
With the X resource `Emacs.Font', you can specify a fontset name
just like an actual font name. But be careful not to specify a fontset
name in a wildcard resource like `Emacs*Font'--that wildcard
specification applies to various other purposes, such as menus, and
menus cannot handle fontsets.
You can specify additional fontsets using X resources named
`Fontset-N', where N is an integer starting from 0. The resource value
should have this form:
FONTPATTERN, [CHARSETNAME:FONTNAME]...
FONTPATTERN should have the form of a standard X font name, except for
the last two fields. They should have the form `fontset-ALIAS'.
The fontset has two names, one long and one short. The long name is
FONTPATTERN. The short name is `fontset-ALIAS'. You can refer to the
fontset by either name.
The construct `CHARSET:FONT' specifies which font to use (in this
fontset) for one particular character set. Here, CHARSET is the name
of a character set, and FONT is the font to use for that character set.
You can use this construct any number of times in defining one fontset.
For the other character sets, Emacs chooses a font based on
FONTPATTERN. It replaces `fontset-ALIAS' with values that describe the
character set. For the ASCII character font, `fontset-ALIAS' is
replaced with `ISO8859-1'.
In addition, when several consecutive fields are wildcards, Emacs
collapses them into a single wildcard. This is to prevent use of
auto-scaled fonts. Fonts made by scaling larger fonts are not usable
for editing, and scaling a smaller font is not useful because it is
better to use the smaller font in its own size, which Emacs does.
Thus if FONTPATTERN is this,
-*-fixed-medium-r-normal-*-24-*-*-*-*-*-fontset-24
the font specification for ASCII characters would be this:
-*-fixed-medium-r-normal-*-24-*-ISO8859-1
and the font specification for Chinese GB2312 characters would be this:
-*-fixed-medium-r-normal-*-24-*-gb2312*-*
You may not have any Chinese font matching the above font
specification. Most X distributions include only Chinese fonts that
have `song ti' or `fangsong ti' in FAMILY field. In such a case,
`Fontset-N' can be specified as below:
Emacs.Fontset-0: -*-fixed-medium-r-normal-*-24-*-*-*-*-*-fontset-24,\
chinese-gb2312:-*-*-medium-r-normal-*-24-*-gb2312*-*
Then, the font specifications for all but Chinese GB2312 characters have
`fixed' in the FAMILY field, and the font specification for Chinese
GB2312 characters has a wild card `*' in the FAMILY field.
The function that processes the fontset resource value to create the
fontset is called `create-fontset-from-fontset-spec'. You can also
call this function explicitly to create a fontset.
*Note Font X::, for more information about font naming in X.
Single-byte European Character Support
======================================
The ISO 8859 Latin-N character sets define character codes in the
range 160 to 255 to handle the accented letters and punctuation needed
by various European languages. If you disable multibyte characters,
Emacs can still handle *one* of these character codes at a time. To
specify *which* of these codes to use, invoke `M-x
set-language-environment' and specify a suitable language environment
such as `Latin-N'.
For more information about unibyte operation, see *Note Enabling
Multibyte::. Note particularly that you probably want to ensure that
your initialization files are read as unibyte if they contain non-ASCII
characters.
Emacs can also display those characters, provided the terminal or
font in use supports them. This works automatically. Alternatively,
if you are using a window system, Emacs can also display single-byte
characters through fontsets, in effect by displaying the equivalent
multibyte characters according to the current language environment. To
request this, set the variable
`unibyte-display-via-language-environment' to a non-`nil' value.
If your terminal does not support display of the Latin-1 character
set, Emacs can display these characters as ASCII sequences which at
least give you a clear idea of what the characters are. To do this,
load the library `iso-ascii'. Similar libraries for other Latin-N
character sets could be implemented, but we don't have them yet.
Normally non-ISO-8859 characters (between characters 128 and 159
inclusive) are displayed as octal escapes. You can change this for
non-standard `extended' versions of ISO-8859 character sets by using the
function `standard-display-8bit' in the `disp-table' library.
There are three different ways you can input single-byte non-ASCII
characters:
* If your keyboard can generate character codes 128 and up,
representing non-ASCII characters, execute the following
expression to enable Emacs to understand them:
(set-input-mode (car (current-input-mode))
(nth 1 (current-input-mode))
0)
* You can use an input method for the selected language environment.
*Note Input Methods::. When you use an input method in a unibyte
buffer, the non-ASCII character you specify with it is converted
to unibyte.
* For Latin-1 only, you can use the key `C-x 8' as a "compose
character" prefix for entry of non-ASCII Latin-1 printing
characters. `C-x 8' is good for insertion (in the minibuffer as
well as other buffers), for searching, and in any other context
where a key sequence is allowed.
`C-x 8' works by loading the `iso-transl' library. Once that
library is loaded, the <ALT> modifier key, if you have one, serves
the same purpose as `C-x 8'; use <ALT> together with an accent
character to modify the following letter. In addition, if you
have keys for the Latin-1 "dead accent characters", they too are
defined to compose with the following character, once `iso-transl'
is loaded.
Major Modes
***********
Emacs provides many alternative "major modes", each of which
customizes Emacs for editing text of a particular sort. The major modes
are mutually exclusive, and each buffer has one major mode at any time.
The mode line normally shows the name of the current major mode, in
parentheses (*note Mode Line::.).
The least specialized major mode is called "Fundamental mode". This
mode has no mode-specific redefinitions or variable settings, so that
each Emacs command behaves in its most general manner, and each option
is in its default state. For editing text of a specific type that
Emacs knows about, such as Lisp code or English text, you should switch
to the appropriate major mode, such as Lisp mode or Text mode.
Selecting a major mode changes the meanings of a few keys to become
more specifically adapted to the language being edited. The ones that
are changed frequently are <TAB>, <DEL>, and `C-j'. The prefix key
`C-c' normally contains mode-specific commands. In addition, the
commands which handle comments use the mode to determine how comments
are to be delimited. Many major modes redefine the syntactical
properties of characters appearing in the buffer. *Note Syntax::.
The major modes fall into three major groups. Lisp mode (which has
several variants), C mode, Fortran mode and others are for specific
programming languages. Text mode, Nroff mode, TeX mode and Outline
mode are for editing English text. The remaining major modes are not
intended for use on users' files; they are used in buffers created for
specific purposes by Emacs, such as Dired mode for buffers made by Dired
(*note Dired::.), Mail mode for buffers made by `C-x m' (*note Sending
Mail::.), and Shell mode for buffers used for communicating with an
inferior shell process (*note Interactive Shell::.).
Most programming-language major modes specify that only blank lines
separate paragraphs. This is to make the paragraph commands useful.
(*Note Paragraphs::.) They also cause Auto Fill mode to use the
definition of <TAB> to indent the new lines it creates. This is
because most lines in a program are usually indented. (*Note
Indentation::.)
How Major Modes are Chosen
==========================
You can select a major mode explicitly for the current buffer, but
most of the time Emacs determines which mode to use based on the file
name or on special text in the file.
Explicit selection of a new major mode is done with a `M-x' command.
From the name of a major mode, add `-mode' to get the name of a command
to select that mode. Thus, you can enter Lisp mode by executing `M-x
lisp-mode'.
When you visit a file, Emacs usually chooses the right major mode
based on the file's name. For example, files whose names end in `.c'
are edited in C mode. The correspondence between file names and major
modes is controlled by the variable `auto-mode-alist'. Its value is a
list in which each element has this form,
(REGEXP . MODE-FUNCTION)
or this form,
(REGEXP MODE-FUNCTION FLAG)
For example, one element normally found in the list has the form
`("\\.c\\'" . c-mode)', and it is responsible for selecting C mode for
files whose names end in `.c'. (Note that `\\' is needed in Lisp
syntax to include a `\' in the string, which is needed to suppress the
special meaning of `.' in regexps.) If the element has the form
`(REGEXP MODE-FUNCTION FLAG)' and FLAG is non-`nil', then after calling
FUNCTION, the suffix that matched REGEXP is discarded and the list is
searched again for another match.
You can specify which major mode should be used for editing a certain
file by a special sort of text in the first nonblank line of the file.
The mode name should appear in this line both preceded and followed by
`-*-'. Other text may appear on the line as well. For example,
;-*-Lisp-*-
tells Emacs to use Lisp mode. Such an explicit specification overrides
any defaulting based on the file name. Note how the semicolon is used
to make Lisp treat this line as a comment.
Another format of mode specification is
-*- mode: MODENAME;-*-
which allows you to specify local variables as well, like this:
-*- mode: MODENAME; VAR: VALUE; ... -*-
*Note File Variables::, for more information about this.
When a file's contents begin with `#!', it can serve as an
executable shell command, which works by running an interpreter named on
the file's first line. The rest of the file is used as input to the
interpreter.
When you visit such a file in Emacs, if the file's name does not
specify a major mode, Emacs uses the interpreter name on the first line
to choose a mode. If the first line is the name of a recognized
interpreter program, such as `perl' or `tcl', Emacs uses a mode
appropriate for programs for that interpreter. The variable
`interpreter-mode-alist' specifies the correspondence between
interpreter program names and major modes.
When the first line starts with `#!', you cannot (on many systems)
use the `-*-' feature on the first line, because the system would get
confused when running the interpreter. So Emacs looks for `-*-' on the
second line in such files as well as on the first line.
When you visit a file that does not specify a major mode to use, or
when you create a new buffer with `C-x b', the variable
`default-major-mode' specifies which major mode to use. Normally its
value is the symbol `fundamental-mode', which specifies Fundamental
mode. If `default-major-mode' is `nil', the major mode is taken from
the previously selected buffer.
If you change the major mode of a buffer, you can go back to the
major mode Emacs would choose automatically: use the command `M-x
normal-mode' to do this. This is the same function that `find-file'
calls to choose the major mode. It also processes the file's local
variables list if any.
The commands `C-x C-w' and `set-visited-file-name' change to a new
major mode if the new file name implies a mode (*note Saving::.).
However, this does not happen if the buffer contents specify a major
mode, and certain "special" major modes do not allow the mode to
change. You can turn off this mode-changing feature by setting
`change-major-mode-with-file-name' to `nil'.
Indentation
***********
This chapter describes the Emacs commands that add, remove, or
adjust indentation.
`<TAB>'
Indent current line "appropriately" in a mode-dependent fashion.
`C-j'
Perform <RET> followed by <TAB> (`newline-and-indent').
`M-^'
Merge two lines (`delete-indentation'). This would cancel out the
effect of `C-j'.
`C-M-o'
Split line at point; text on the line after point becomes a new
line indented to the same column that it now starts in
(`split-line').
`M-m'
Move (forward or back) to the first nonblank character on the
current line (`back-to-indentation').
`C-M-\'
Indent several lines to same column (`indent-region').
`C-x <TAB>'
Shift block of lines rigidly right or left (`indent-rigidly').
`M-i'
Indent from point to the next prespecified tab stop column
(`tab-to-tab-stop').
`M-x indent-relative'
Indent from point to under an indentation point in the previous
line.
Most programming languages have some indentation convention. For
Lisp code, lines are indented according to their nesting in
parentheses. The same general idea is used for C code, though many
details are different.
Whatever the language, to indent a line, use the <TAB> command. Each
major mode defines this command to perform the sort of indentation
appropriate for the particular language. In Lisp mode, <TAB> aligns
the line according to its depth in parentheses. No matter where in the
line you are when you type <TAB>, it aligns the line as a whole. In C
mode, <TAB> implements a subtle and sophisticated indentation style that
knows about many aspects of C syntax.
In Text mode, <TAB> runs the command `tab-to-tab-stop', which
indents to the next tab stop column. You can set the tab stops with
`M-x edit-tab-stops'.
Indentation Commands and Techniques
===================================
To move over the indentation on a line, do `M-m'
(`back-to-indentation'). This command, given anywhere on a line,
positions point at the first nonblank character on the line.
To insert an indented line before the current line, do `C-a C-o
<TAB>'. To make an indented line after the current line, use `C-e C-j'.
If you just want to insert a tab character in the buffer, you can
type `C-q <TAB>'.
`C-M-o' (`split-line') moves the text from point to the end of the
line vertically down, so that the current line becomes two lines.
`C-M-o' first moves point forward over any spaces and tabs. Then it
inserts after point a newline and enough indentation to reach the same
column point is on. Point remains before the inserted newline; in this
regard, `C-M-o' resembles `C-o'.
To join two lines cleanly, use the `M-^' (`delete-indentation')
command. It deletes the indentation at the front of the current line,
and the line boundary as well, replacing them with a single space. As
a special case (useful for Lisp code) the single space is omitted if
the characters to be joined are consecutive open parentheses or closing
parentheses, or if the junction follows another newline. To delete
just the indentation of a line, go to the beginning of the line and use
`M-\' (`delete-horizontal-space'), which deletes all spaces and tabs
around the cursor.
If you have a fill prefix, `M-^' deletes the fill prefix if it
appears after the newline that is deleted. *Note Fill Prefix::.
There are also commands for changing the indentation of several lines
at once. `C-M-\' (`indent-region') applies to all the lines that begin
in the region; it indents each line in the "usual" way, as if you had
typed <TAB> at the beginning of the line. A numeric argument specifies
the column to indent to, and each line is shifted left or right so that
its first nonblank character appears in that column. `C-x <TAB>'
(`indent-rigidly') moves all of the lines in the region right by its
argument (left, for negative arguments). The whole group of lines
moves rigidly sideways, which is how the command gets its name.
`M-x indent-relative' indents at point based on the previous line
(actually, the last nonempty line). It inserts whitespace at point,
moving point, until it is underneath an indentation point in the
previous line. An indentation point is the end of a sequence of
whitespace or the end of the line. If point is farther right than any
indentation point in the previous line, the whitespace before point is
deleted and the first indentation point then applicable is used. If no
indentation point is applicable even then, `indent-relative' runs
`tab-to-tab-stop' (*note Tab Stops::.).
`indent-relative' is the definition of <TAB> in Indented Text mode.
*Note Text::.
*Note Format Indentation::, for another way of specifying the
indentation for part of your text.
Tab Stops
=========
For typing in tables, you can use Text mode's definition of <TAB>,
`tab-to-tab-stop'. This command inserts indentation before point,
enough to reach the next tab stop column. If you are not in Text mode,
this command can be found on the key `M-i'.
You can specify the tab stops used by `M-i'. They are stored in a
variable called `tab-stop-list', as a list of column-numbers in
increasing order.
The convenient way to set the tab stops is with `M-x
edit-tab-stops', which creates and selects a buffer containing a
description of the tab stop settings. You can edit this buffer to
specify different tab stops, and then type `C-c C-c' to make those new
tab stops take effect. `edit-tab-stops' records which buffer was
current when you invoked it, and stores the tab stops back in that
buffer; normally all buffers share the same tab stops and changing them
in one buffer affects all, but if you happen to make `tab-stop-list'
local in one buffer then `edit-tab-stops' in that buffer will edit the
local settings.
Here is what the text representing the tab stops looks like for
ordinary tab stops every eight columns.
: : : : : :
0 1 2 3 4
0123456789012345678901234567890123456789012345678
To install changes, type C-c C-c
The first line contains a colon at each tab stop. The remaining
lines are present just to help you see where the colons are and know
what to do.
Note that the tab stops that control `tab-to-tab-stop' have nothing
to do with displaying tab characters in the buffer. *Note Display
Vars::, for more information on that.
Tabs vs. Spaces
===============
Emacs normally uses both tabs and spaces to indent lines. If you
prefer, all indentation can be made from spaces only. To request this,
set `indent-tabs-mode' to `nil'. This is a per-buffer variable;
altering the variable affects only the current buffer, but there is a
default value which you can change as well. *Note Locals::.
There are also commands to convert tabs to spaces or vice versa,
always preserving the columns of all nonblank text. `M-x tabify' scans
the region for sequences of spaces, and converts sequences of at least
three spaces to tabs if that can be done without changing indentation.
`M-x untabify' changes all tabs in the region to appropriate numbers of
spaces.
Commands for Human Languages
****************************
The term "text" has two widespread meanings in our area of the
computer field. One is data that is a sequence of characters. Any file
that you edit with Emacs is text, in this sense of the word. The other
meaning is more restrictive: a sequence of characters in a human
language for humans to read (possibly after processing by a text
formatter), as opposed to a program or commands for a program.
Human languages have syntactic/stylistic conventions that can be
supported or used to advantage by editor commands: conventions involving
words, sentences, paragraphs, and capital letters. This chapter
describes Emacs commands for all of these things. There are also
commands for "filling", which means rearranging the lines of a
paragraph to be approximately equal in length. The commands for moving
over and killing words, sentences and paragraphs, while intended
primarily for editing text, are also often useful for editing programs.
Emacs has several major modes for editing human-language text. If
the file contains text pure and simple, use Text mode, which customizes
Emacs in small ways for the syntactic conventions of text. Outline mode
provides special commands for operating on text with an outline
structure.
For text which contains embedded commands for text formatters, Emacs
has other major modes, each for a particular text formatter. Thus, for
input to TeX, you would use TeX mode. For input to nroff, use Nroff
mode.
Instead of using a text formatter, you can edit formatted text in
WYSIWYG style ("what you see is what you get"), with Enriched mode.
Then the formatting appears on the screen in Emacs while you edit.
Words
=====
Emacs has commands for moving over or operating on words. By
convention, the keys for them are all Meta characters.
`M-f'
Move forward over a word (`forward-word').
`M-b'
Move backward over a word (`backward-word').
`M-d'
Kill up to the end of a word (`kill-word').
`M-<DEL>'
Kill back to the beginning of a word (`backward-kill-word').
`M-@'
Mark the end of the next word (`mark-word').
`M-t'
Transpose two words or drag a word across other words
(`transpose-words').
Notice how these keys form a series that parallels the
character-based `C-f', `C-b', `C-d', <DEL> and `C-t'. `M-@' is cognate
to `C-@', which is an alias for `C-<SPC>'.
The commands `M-f' (`forward-word') and `M-b' (`backward-word') move
forward and backward over words. These Meta characters are thus
analogous to the corresponding control characters, `C-f' and `C-b',
which move over single characters in the text. The analogy extends to
numeric arguments, which serve as repeat counts. `M-f' with a negative
argument moves backward, and `M-b' with a negative argument moves
forward. Forward motion stops right after the last letter of the word,
while backward motion stops right before the first letter.
`M-d' (`kill-word') kills the word after point. To be precise, it
kills everything from point to the place `M-f' would move to. Thus, if
point is in the middle of a word, `M-d' kills just the part after
point. If some punctuation comes between point and the next word, it
is killed along with the word. (If you wish to kill only the next word
but not the punctuation before it, simply do `M-f' to get the end, and
kill the word backwards with `M-<DEL>'.) `M-d' takes arguments just
like `M-f'.
`M-<DEL>' (`backward-kill-word') kills the word before point. It
kills everything from point back to where `M-b' would move to. If
point is after the space in `FOO, BAR', then `FOO, ' is killed. (If
you wish to kill just `FOO', and not the comma and the space, use `M-b
M-d' instead of `M-<DEL>'.)
`M-t' (`transpose-words') exchanges the word before or containing
point with the following word. The delimiter characters between the
words do not move. For example, `FOO, BAR' transposes into `BAR, FOO'
rather than `BAR FOO,'. *Note Transpose::, for more on transposition
and on arguments to transposition commands.
To operate on the next N words with an operation which applies
between point and mark, you can either set the mark at point and then
move over the words, or you can use the command `M-@' (`mark-word')
which does not move point, but sets the mark where `M-f' would move to.
`M-@' accepts a numeric argument that says how many words to scan for
the place to put the mark. In Transient Mark mode, this command
activates the mark.
The word commands' understanding of syntax is completely controlled
by the syntax table. Any character can, for example, be declared to be
a word delimiter. *Note Syntax::.
Sentences
=========
The Emacs commands for manipulating sentences and paragraphs are
mostly on Meta keys, so as to be like the word-handling commands.
`M-a'
Move back to the beginning of the sentence (`backward-sentence').
`M-e'
Move forward to the end of the sentence (`forward-sentence').
`M-k'
Kill forward to the end of the sentence (`kill-sentence').
`C-x <DEL>'
Kill back to the beginning of the sentence
(`backward-kill-sentence').
The commands `M-a' and `M-e' (`backward-sentence' and
`forward-sentence') move to the beginning and end of the current
sentence, respectively. They were chosen to resemble `C-a' and `C-e',
which move to the beginning and end of a line. Unlike them, `M-a' and
`M-e' if repeated or given numeric arguments move over successive
sentences.
Moving backward over a sentence places point just before the first
character of the sentence; moving forward places point right after the
punctuation that ends the sentence. Neither one moves over the
whitespace at the sentence boundary.
Just as `C-a' and `C-e' have a kill command, `C-k', to go with them,
so `M-a' and `M-e' have a corresponding kill command `M-k'
(`kill-sentence') which kills from point to the end of the sentence.
With minus one as an argument it kills back to the beginning of the
sentence. Larger arguments serve as a repeat count. There is also a
command, `C-x <DEL>' (`backward-kill-sentence'), for killing back to
the beginning of a sentence. This command is useful when you change
your mind in the middle of composing text.
The sentence commands assume that you follow the American typist's
convention of putting two spaces at the end of a sentence; they consider
a sentence to end wherever there is a `.', `?' or `!' followed by the
end of a line or two spaces, with any number of `)', `]', `'', or `"'
characters allowed in between. A sentence also begins or ends wherever
a paragraph begins or ends.
The variable `sentence-end' controls recognition of the end of a
sentence. It is a regexp that matches the last few characters of a
sentence, together with the whitespace following the sentence. Its
normal value is
"[.?!][]\"')]*\\($\\|\t\\| \\)[ \t\n]*"
This example is explained in the section on regexps. *Note Regexps::.
If you want to use just one space between sentences, you should set
`sentence-end' to this value:
"[.?!][]\"')]*\\($\\|\t\\| \\)[ \t\n]*"
You should also set the variable `sentence-end-double-space' to `nil'
so that the fill commands expect and leave just one space at the end of
a sentence. Note that this makes it impossible to distinguish between
periods that end sentences and those that indicate abbreviations.
Paragraphs
==========
The Emacs commands for manipulating paragraphs are also Meta keys.
`M-{'
Move back to previous paragraph beginning (`backward-paragraph').
`M-}'
Move forward to next paragraph end (`forward-paragraph').
`M-h'
Put point and mark around this or next paragraph
(`mark-paragraph').
`M-{' moves to the beginning of the current or previous paragraph,
while `M-}' moves to the end of the current or next paragraph. Blank
lines and text-formatter command lines separate paragraphs and are not
considered part of any paragraph. In Fundamental mode, but not in Text
mode, an indented line also starts a new paragraph. (If a paragraph is
preceded by a blank line, these commands treat that blank line as the
beginning of the paragraph.)
In major modes for programs, paragraphs begin and end only at blank
lines. This makes the paragraph commands continue to be useful even
though there are no paragraphs per se.
When there is a fill prefix, then paragraphs are delimited by all
lines which don't start with the fill prefix. *Note Filling::.
When you wish to operate on a paragraph, you can use the command
`M-h' (`mark-paragraph') to set the region around it. Thus, for
example, `M-h C-w' kills the paragraph around or after point. The
`M-h' command puts point at the beginning and mark at the end of the
paragraph point was in. In Transient Mark mode, it activates the mark.
If point is between paragraphs (in a run of blank lines, or at a
boundary), the paragraph following point is surrounded by point and
mark. If there are blank lines preceding the first line of the
paragraph, one of these blank lines is included in the region.
The precise definition of a paragraph boundary is controlled by the
variables `paragraph-separate' and `paragraph-start'. The value of
`paragraph-start' is a regexp that should match any line that either
starts or separates paragraphs. The value of `paragraph-separate' is
another regexp that should match only lines that separate paragraphs
without being part of any paragraph (for example, blank lines). Lines
that start a new paragraph and are contained in it must match only
`paragraph-start', not `paragraph-separate'. For example, in
Fundamental mode, `paragraph-start' is `"[ \t\n\f]"' and
`paragraph-separate' is `"[ \t\f]*$"'.
Normally it is desirable for page boundaries to separate paragraphs.
The default values of these variables recognize the usual separator for
pages.
Pages
=====
Files are often thought of as divided into "pages" by the "formfeed"
character (ASCII control-L, octal code 014). When you print hardcopy
for a file, this character forces a page break; thus, each page of the
file goes on a separate page on paper. Most Emacs commands treat the
page-separator character just like any other character: you can insert
it with `C-q C-l', and delete it with <DEL>. Thus, you are free to
paginate your file or not. However, since pages are often meaningful
divisions of the file, Emacs provides commands to move over them and
operate on them.
`C-x ['
Move point to previous page boundary (`backward-page').
`C-x ]'
Move point to next page boundary (`forward-page').
`C-x C-p'
Put point and mark around this page (or another page)
(`mark-page').
`C-x l'
Count the lines in this page (`count-lines-page').
The `C-x [' (`backward-page') command moves point to immediately
after the previous page delimiter. If point is already right after a
page delimiter, it skips that one and stops at the previous one. A
numeric argument serves as a repeat count. The `C-x ]' (`forward-page')
command moves forward past the next page delimiter.
The `C-x C-p' command (`mark-page') puts point at the beginning of
the current page and the mark at the end. The page delimiter at the
end is included (the mark follows it). The page delimiter at the front
is excluded (point follows it). `C-x C-p C-w' is a handy way to kill a
page to move it elsewhere. If you move to another page delimiter with
`C-x [' and `C-x ]', then yank the killed page, all the pages will be
properly delimited once again. The reason `C-x C-p' includes only the
following page delimiter in the region is to ensure that.
A numeric argument to `C-x C-p' is used to specify which page to go
to, relative to the current one. Zero means the current page. One
means the next page, and -1 means the previous one.
The `C-x l' command (`count-lines-page') is good for deciding where
to break a page in two. It prints in the echo area the total number of
lines in the current page, and then divides it up into those preceding
the current line and those following, as in
Page has 96 (72+25) lines
Notice that the sum is off by one; this is correct if point is not at
the beginning of a line.
The variable `page-delimiter' controls where pages begin. Its value
is a regexp that matches the beginning of a line that separates pages.
The normal value of this variable is `"^\f"', which matches a formfeed
character at the beginning of a line.
Filling Text
============
"Filling" text means breaking it up into lines that fit a specified
width. Emacs does filling in two ways. In Auto Fill mode, inserting
text with self-inserting characters also automatically fills it. There
are also explicit fill commands that you can use when editing text
leaves it unfilled. When you edit formatted text, you can specify a
style of filling for each portion of the text (*note Formatted Text::.).
Auto Fill Mode
--------------
"Auto Fill" mode is a minor mode in which lines are broken
automatically when they become too wide. Breaking happens only when
you type a <SPC> or <RET>.
`M-x auto-fill-mode'
Enable or disable Auto Fill mode.
`<SPC>'
`<RET>'
In Auto Fill mode, break lines when appropriate.
`M-x auto-fill-mode' turns Auto Fill mode on if it was off, or off
if it was on. With a positive numeric argument it always turns Auto
Fill mode on, and with a negative argument always turns it off. You can
see when Auto Fill mode is in effect by the presence of the word `Fill'
in the mode line, inside the parentheses. Auto Fill mode is a minor
mode which is enabled or disabled for each buffer individually. *Note
Minor Modes::.
In Auto Fill mode, lines are broken automatically at spaces when they
get longer than the desired width. Line breaking and rearrangement
takes place only when you type <SPC> or <RET>. If you wish to insert a
space or newline without permitting line-breaking, type `C-q <SPC>' or
`C-q C-j' (recall that a newline is really a control-J). Also, `C-o'
inserts a newline without line breaking.
Auto Fill mode works well with programming-language modes, because it
indents new lines with <TAB>. If a line ending in a comment gets too
long, the text of the comment is split into two comment lines.
Optionally, new comment delimiters are inserted at the end of the first
line and the beginning of the second so that each line is a separate
comment; the variable `comment-multi-line' controls the choice (*note
Comments::.).
Adaptive filling (see the following section) works for Auto Filling
as well as for explicit fill commands. It takes a fill prefix
automatically from the second or first line of a paragraph.
Auto Fill mode does not refill entire paragraphs; it can break lines
but cannot merge lines. So editing in the middle of a paragraph can
result in a paragraph that is not correctly filled. The easiest way to
make the paragraph properly filled again is usually with the explicit
fill commands. *Note Fill Commands::.
Many users like Auto Fill mode and want to use it in all text files.
The section on init files says how to arrange this permanently for
yourself. *Note Init File::.
Explicit Fill Commands
----------------------
`M-q'
Fill current paragraph (`fill-paragraph').
`C-x f'
Set the fill column (`set-fill-column').
`M-x fill-region'
Fill each paragraph in the region (`fill-region').
`M-x fill-region-as-paragraph'
Fill the region, considering it as one paragraph.
`M-s'
Center a line.
To refill a paragraph, use the command `M-q' (`fill-paragraph').
This operates on the paragraph that point is inside, or the one after
point if point is between paragraphs. Refilling works by removing all
the line-breaks, then inserting new ones where necessary.
To refill many paragraphs, use `M-x fill-region', which divides the
region into paragraphs and fills each of them.
`M-q' and `fill-region' use the same criteria as `M-h' for finding
paragraph boundaries (*note Paragraphs::.). For more control, you can
use `M-x fill-region-as-paragraph', which refills everything between
point and mark. This command deletes any blank lines within the
region, so separate blocks of text end up combined into one block.
A numeric argument to `M-q' causes it to "justify" the text as well
as filling it. This means that extra spaces are inserted to make the
right margin line up exactly at the fill column. To remove the extra
spaces, use `M-q' with no argument. (Likewise for `fill-region'.)
Another way to control justification, and choose other styles of
filling, is with the `justification' text property; see *Note Format
Justification::.
The command `M-s' (`center-line') centers the current line within
the current fill column. With an argument N, it centers N lines
individually and moves past them.
The maximum line width for filling is in the variable `fill-column'.
Altering the value of `fill-column' makes it local to the current
buffer; until that time, the default value is in effect. The default
is initially 70. *Note Locals::. The easiest way to set `fill-column'
is to use the command `C-x f' (`set-fill-column'). With a numeric
argument, it uses that as the new fill column. With just `C-u' as
argument, it sets `fill-column' to the current horizontal position of
point.
Emacs commands normally consider a period followed by two spaces or
by a newline as the end of a sentence; a period followed by just one
space indicates an abbreviation and not the end of a sentence. To
preserve the distinction between these two ways of using a period, the
fill commands do not break a line after a period followed by just one
space.
If the variable `sentence-end-double-space' is `nil', the fill
commands expect and leave just one space at the end of a sentence.
Ordinarily this variable is `t', so the fill commands insist on two
spaces for the end of a sentence, as explained above. *Note
Sentences::.
If the variable `colon-double-space' is non-`nil', the fill commands
put two spaces after a colon.
The Fill Prefix
---------------
To fill a paragraph in which each line starts with a special marker
(which might be a few spaces, giving an indented paragraph), you can use
the "fill prefix" feature. The fill prefix is a string that Emacs
expects every line to start with, and which is not included in filling.
You can specify a fill prefix explicitly; Emacs can also deduce the
fill prefix automatically (*note Adaptive Fill::.).
`C-x .'
Set the fill prefix (`set-fill-prefix').
`M-q'
Fill a paragraph using current fill prefix (`fill-paragraph').
`M-x fill-individual-paragraphs'
Fill the region, considering each change of indentation as
starting a new paragraph.
`M-x fill-nonuniform-paragraphs'
Fill the region, considering only paragraph-separator lines as
starting a new paragraph.
To specify a fill prefix, move to a line that starts with the desired
prefix, put point at the end of the prefix, and give the command
`C-x .' (`set-fill-prefix'). That's a period after the `C-x'. To turn
off the fill prefix, specify an empty prefix: type `C-x .' with point
at the beginning of a line.
When a fill prefix is in effect, the fill commands remove the fill
prefix from each line before filling and insert it on each line after
filling. Auto Fill mode also inserts the fill prefix automatically when
it makes a new line. The `C-o' command inserts the fill prefix on new
lines it creates, when you use it at the beginning of a line (*note
Blank Lines::.). Conversely, the command `M-^' deletes the prefix (if
it occurs) after the newline that it deletes (*note Indentation::.).
For example, if `fill-column' is 40 and you set the fill prefix to
`;; ', then `M-q' in the following text
;; This is an
;; example of a paragraph
;; inside a Lisp-style comment.
produces this:
;; This is an example of a paragraph
;; inside a Lisp-style comment.
Lines that do not start with the fill prefix are considered to start
paragraphs, both in `M-q' and the paragraph commands; this gives good
results for paragraphs with hanging indentation (every line indented
except the first one). Lines which are blank or indented once the
prefix is removed also separate or start paragraphs; this is what you
want if you are writing multi-paragraph comments with a comment
delimiter on each line.
You can use `M-x fill-individual-paragraphs' to set the fill prefix
for each paragraph automatically. This command divides the region into
paragraphs, treating every change in the amount of indentation as the
start of a new paragraph, and fills each of these paragraphs. Thus,
all the lines in one "paragraph" have the same amount of indentation.
That indentation serves as the fill prefix for that paragraph.
`M-x fill-nonuniform-paragraphs' is a similar command that divides
the region into paragraphs in a different way. It considers only
paragraph-separating lines (as defined by `paragraph-separate') as
starting a new paragraph. Since this means that the lines of one
paragraph may have different amounts of indentation, the fill prefix
used is the smallest amount of indentation of any of the lines of the
paragraph. This gives good results with styles that indent a
paragraph's first line more or less that the rest of the paragraph.
The fill prefix is stored in the variable `fill-prefix'. Its value
is a string, or `nil' when there is no fill prefix. This is a
per-buffer variable; altering the variable affects only the current
buffer, but there is a default value which you can change as well.
*Note Locals::.
The `indentation' text property provides another way to control the
amount of indentation paragraphs receive. *Note Format Indentation::.
Adaptive Filling
----------------
The fill commands can deduce the proper fill prefix for a paragraph
automatically in certain cases: either whitespace or certain punctuation
characters at the beginning of a line are propagated to all lines of the
paragraph.
If the paragraph has two or more lines, the fill prefix is taken from
the paragraph's second line, but only if it appears on the first line as
well.
If a paragraph has just one line, fill commands *may* take a prefix
from that line. The decision is complicated because there are three
reasonable things to do in such a case:
* Use the first line's prefix on all the lines of the paragraph.
* Indent subsequent lines with whitespace, so that they line up
under the text that follows the prefix on the first line, but
don't actually copy the prefix from the first line.
* Don't do anything special with the second and following lines.
All three of these styles of formatting are commonly used. So the
fill commands try to determine what you would like, based on the prefix
that appears and on the major mode. Here is how.
If the prefix found on the first line matches
`adaptive-fill-first-line-regexp', or if it appears to be a
comment-starting sequence (this depends on the major mode), then the
prefix found is used for filling the paragraph, provided it would not
act as a paragraph starter on subsequent lines.
Otherwise, the prefix found is converted to an equivalent number of
spaces, and those spaces are used as the fill prefix for the rest of the
lines, provided they would not act as a paragraph starter on subsequent
lines.
In Text mode, and other modes where only blank lines and page
delimiters separate paragraphs, the prefix chosen by adaptive filling
never acts as a paragraph starter, so it can always be used for filling.
The variable `adaptive-fill-regexp' determines what kinds of line
beginnings can serve as a fill prefix: any characters at the start of
the line that match this regular expression are used. If you set the
variable `adaptive-fill-mode' to `nil', the fill prefix is never chosen
automatically.
You can specify more complex ways of choosing a fill prefix
automatically by setting the variable `adaptive-fill-function' to a
function. This function is called with point after the left margin of a
line, and it should return the appropriate fill prefix based on that
line. If it returns `nil', that means it sees no fill prefix in that
line.
Case Conversion Commands
========================
Emacs has commands for converting either a single word or any
arbitrary range of text to upper case or to lower case.
`M-l'
Convert following word to lower case (`downcase-word').
`M-u'
Convert following word to upper case (`upcase-word').
`M-c'
Capitalize the following word (`capitalize-word').
`C-x C-l'
Convert region to lower case (`downcase-region').
`C-x C-u'
Convert region to upper case (`upcase-region').
The word conversion commands are the most useful. `M-l'
(`downcase-word') converts the word after point to lower case, moving
past it. Thus, repeating `M-l' converts successive words. `M-u'
(`upcase-word') converts to all capitals instead, while `M-c'
(`capitalize-word') puts the first letter of the word into upper case
and the rest into lower case. All these commands convert several words
at once if given an argument. They are especially convenient for
converting a large amount of text from all upper case to mixed case,
because you can move through the text using `M-l', `M-u' or `M-c' on
each word as appropriate, occasionally using `M-f' instead to skip a
word.
When given a negative argument, the word case conversion commands
apply to the appropriate number of words before point, but do not move
point. This is convenient when you have just typed a word in the wrong
case: you can give the case conversion command and continue typing.
If a word case conversion command is given in the middle of a word,
it applies only to the part of the word which follows point. This is
just like what `M-d' (`kill-word') does. With a negative argument,
case conversion applies only to the part of the word before point.
The other case conversion commands are `C-x C-u' (`upcase-region')
and `C-x C-l' (`downcase-region'), which convert everything between
point and mark to the specified case. Point and mark do not move.
The region case conversion commands `upcase-region' and
`downcase-region' are normally disabled. This means that they ask for
confirmation if you try to use them. When you confirm, you may enable
the command, which means it will not ask for confirmation again. *Note
Disabling::.
Text Mode
=========
When you edit files of text in a human language, it's more convenient
to use Text mode rather than Fundamental mode. To enter Text mode, type
`M-x text-mode'.
In Text mode, only blank lines and page delimiters separate
paragraphs. As a result, paragraphs can be indented, and adaptive
filling determines what indentation to use when filling a paragraph.
*Note Adaptive Fill::.
Text mode defines <TAB> to run `indent-relative' (*note
Indentation::.), so that you can conveniently indent a line like the
previous line. When the previous line is not indented,
`indent-relative' runs `tab-to-tab-stop', which uses Emacs tab stops
that you can set (*note Tab Stops::.).
Text mode turns off the features concerned with comments except when
you explicitly invoke them. It changes the syntax table so that periods
are not considered part of a word, while apostrophes, backspaces and
underlines are considered part of words.
If you indent the first lines of paragraphs, then you should use
Paragraph-Indent Text mode rather than Text mode. In this mode, you do
not need to have blank lines between paragraphs, because the first-line
indentation is sufficient to start a paragraph; however paragraphs in
which every line is indented are not supported. Use `M-x
paragraph-indent-text-mode' to enter this mode.
Text mode, and all the modes based on it, define `M-<TAB>' as the
command `ispell-complete-word', which performs completion of the
partial word in the buffer before point, using the spelling dictionary
as the space of possible words. *Note Spelling::.
Entering Text mode runs the hook `text-mode-hook'. Other major
modes related to Text mode also run this hook, followed by hooks of
their own; this includes Paragraph-Indent Text mode, Nroff mode, TeX
mode, Outline mode, and Mail mode. Hook functions on `text-mode-hook'
can look at the value of `major-mode' to see which of these modes is
actually being entered. *Note Hooks::.
Emacs provides two other modes for editing text that is to be passed
through a text formatter to produce fancy formatted printed output.
*Note Nroff Mode::, for editing input to the formatter nroff. *Note
TeX Mode::, for editing input to the formatter TeX.
Another mode is used for editing outlines. It allows you to view the
text at various levels of detail. You can view either the outline
headings alone or both headings and text; you can also hide some of the
headings at lower levels from view to make the high level structure more
visible. *Note Outline Mode::.
Outline Mode
============
Outline mode is a major mode much like Text mode but intended for
editing outlines. It allows you to make parts of the text temporarily
invisible so that you can see the outline structure. Type `M-x
outline-mode' to switch to Outline mode as the major mode of the current
buffer.
When Outline mode makes a line invisible, the line does not appear on
the screen. The screen appears exactly as if the invisible line were
deleted, except that an ellipsis (three periods in a row) appears at the
end of the previous visible line (only one ellipsis no matter how many
invisible lines follow).
Editing commands that operate on lines, such as `C-n' and `C-p',
treat the text of the invisible line as part of the previous visible
line. Killing an entire visible line, including its terminating
newline, really kills all the following invisible lines along with it.
Outline minor mode provides the same commands as the major mode,
Outline mode, but you can use it in conjunction with other major modes.
Type `M-x outline-minor-mode' to enable the Outline minor mode in the
current buffer. You can also specify this in the text of a file, with
a file local variable of the form `mode: outline-minor' (*note File
Variables::.).
The major mode, Outline mode, provides special key bindings on the
`C-c' prefix. Outline minor mode provides similar bindings with `C-c
@' as the prefix; this is to reduce the conflicts with the major mode's
special commands. (The variable `outline-minor-mode-prefix' controls
the prefix used.)
Entering Outline mode runs the hook `text-mode-hook' followed by the
hook `outline-mode-hook' (*note Hooks::.).
Format of Outlines
------------------
Outline mode assumes that the lines in the buffer are of two types:
"heading lines" and "body lines". A heading line represents a topic in
the outline. Heading lines start with one or more stars; the number of
stars determines the depth of the heading in the outline structure.
Thus, a heading line with one star is a major topic; all the heading
lines with two stars between it and the next one-star heading are its
subtopics; and so on. Any line that is not a heading line is a body
line. Body lines belong with the preceding heading line. Here is an
example:
* Food
This is the body,
which says something about the topic of food.
** Delicious Food
This is the body of the second-level header.
** Distasteful Food
This could have
a body too, with
several lines.
*** Dormitory Food
* Shelter
Another first-level topic with its header line.
A heading line together with all following body lines is called
collectively an "entry". A heading line together with all following
deeper heading lines and their body lines is called a "subtree".
You can customize the criterion for distinguishing heading lines by
setting the variable `outline-regexp'. Any line whose beginning has a
match for this regexp is considered a heading line. Matches that start
within a line (not at the left margin) do not count. The length of the
matching text determines the level of the heading; longer matches make
a more deeply nested level. Thus, for example, if a text formatter has
commands `@chapter', `@section' and `@subsection' to divide the
document into chapters and sections, you could make those lines count
as heading lines by setting `outline-regexp' to
`"@chap\\|@\\(sub\\)*section"'. Note the trick: the two words
`chapter' and `section' are equally long, but by defining the regexp to
match only `chap' we ensure that the length of the text matched on a
chapter heading is shorter, so that Outline mode will know that
sections are contained in chapters. This works as long as no other
command starts with `@chap'.
It is possible to change the rule for calculating the level of a
heading line by setting the variable `outline-level'. The value of
`outline-level' should be a function that takes no arguments and
returns the level of the current heading. Some major modes such as C,
Nroff, and Emacs Lisp mode set this variable in order to work with
Outline minor mode.
Outline Motion Commands
-----------------------
Outline mode provides special motion commands that move backward and
forward to heading lines.
`C-c C-n'
Move point to the next visible heading line
(`outline-next-visible-heading').
`C-c C-p'
Move point to the previous visible heading line
(`outline-previous-visible-heading').
`C-c C-f'
Move point to the next visible heading line at the same level as
the one point is on (`outline-forward-same-level').
`C-c C-b'
Move point to the previous visible heading line at the same level
(`outline-backward-same-level').
`C-c C-u'
Move point up to a lower-level (more inclusive) visible heading
line (`outline-up-heading').
`C-c C-n' (`outline-next-visible-heading') moves down to the next
heading line. `C-c C-p' (`outline-previous-visible-heading') moves
similarly backward. Both accept numeric arguments as repeat counts.
The names emphasize that invisible headings are skipped, but this is
not really a special feature. All editing commands that look for lines
ignore the invisible lines automatically.
More powerful motion commands understand the level structure of
headings. `C-c C-f' (`outline-forward-same-level') and `C-c C-b'
(`outline-backward-same-level') move from one heading line to another
visible heading at the same depth in the outline. `C-c C-u'
(`outline-up-heading') moves backward to another heading that is less
deeply nested.
Outline Visibility Commands
---------------------------
The other special commands of outline mode are used to make lines
visible or invisible. Their names all start with `hide' or `show'.
Most of them fall into pairs of opposites. They are not undoable;
instead, you can undo right past them. Making lines visible or
invisible is simply not recorded by the undo mechanism.
`C-c C-t'
Make all body lines in the buffer invisible (`hide-body').
`C-c C-a'
Make all lines in the buffer visible (`show-all').
`C-c C-d'
Make everything under this heading invisible, not including this
heading itself (`hide-subtree').
`C-c C-s'
Make everything under this heading visible, including body,
subheadings, and their bodies (`show-subtree').
`C-c C-l'
Make the body of this heading line, and of all its subheadings,
invisible (`hide-leaves').
`C-c C-k'
Make all subheadings of this heading line, at all levels, visible
(`show-branches').
`C-c C-i'
Make immediate subheadings (one level down) of this heading line
visible (`show-children').
`C-c C-c'
Make this heading line's body invisible (`hide-entry').
`C-c C-e'
Make this heading line's body visible (`show-entry').
`C-c C-q'
Hide everything except the top N levels of heading lines
(`hide-sublevels').
`C-c C-o'
Hide everything except for the heading or body that point is in,
plus the headings leading up from there to the top level of the
outline (`hide-other').
Two commands that are exact opposites are `C-c C-c' (`hide-entry')
and `C-c C-e' (`show-entry'). They are used with point on a heading
line, and apply only to the body lines of that heading. Subheadings
and their bodies are not affected.
Two more powerful opposites are `C-c C-d' (`hide-subtree') and `C-c
C-s' (`show-subtree'). Both expect to be used when point is on a
heading line, and both apply to all the lines of that heading's
"subtree": its body, all its subheadings, both direct and indirect, and
all of their bodies. In other words, the subtree contains everything
following this heading line, up to and not including the next heading of
the same or higher rank.
Intermediate between a visible subtree and an invisible one is having
all the subheadings visible but none of the body. There are two
commands for doing this, depending on whether you want to hide the
bodies or make the subheadings visible. They are `C-c C-l'
(`hide-leaves') and `C-c C-k' (`show-branches').
A little weaker than `show-branches' is `C-c C-i' (`show-children').
It makes just the direct subheadings visible--those one level down.
Deeper subheadings remain invisible, if they were invisible.
Two commands have a blanket effect on the whole file. `C-c C-t'
(`hide-body') makes all body lines invisible, so that you see just the
outline structure. `C-c C-a' (`show-all') makes all lines visible.
These commands can be thought of as a pair of opposites even though
`C-c C-a' applies to more than just body lines.
The command `C-c C-q' (`hide-sublevels') hides all but the top level
headings. With a numeric argument N, it hides everything except the
top N levels of heading lines.
The command `C-c C-o' (`hide-other') hides everything except the
heading or body text that point is in, plus its parents (the headers
leading up from there to top level in the outline).
You can turn off the use of ellipses at the ends of visible lines by
setting `selective-display-ellipses' to `nil'. Then there is no
visible indication of the presence of invisible lines.
When incremental search finds text that is hidden by Outline mode,
it makes that part of the buffer visible. If you exit the search at
that position, the text remains visible.
Viewing One Outline in Multiple Views
-------------------------------------
You can display two views of a single outline at the same time, in
different windows. To do this, you must create an indirect buffer using
`M-x make-indirect-buffer'. The first argument of this command is the
existing outline buffer name, and its second argument is the name to
use for the new indirect buffer. *Note Indirect Buffers::.
Once the indirect buffer exists, you can display it in a window in
the normal fashion, with `C-x 4 b' or other Emacs commands. The Outline
mode commands to show and hide parts of the text operate on each buffer
independently; as a result, each buffer can have its own view. If you
want more than two views on the same outline, create additional indirect
buffers.
TeX Mode
========
TeX is a powerful text formatter written by Donald Knuth; it is also
free, like GNU Emacs. LaTeX is a simplified input format for TeX,
implemented by TeX macros; it comes with TeX. SliTeX is a special form
of LaTeX.
Emacs has a special TeX mode for editing TeX input files. It
provides facilities for checking the balance of delimiters and for
invoking TeX on all or part of the file.
TeX mode has three variants, Plain TeX mode, LaTeX mode, and SliTeX
mode (these three distinct major modes differ only slightly). They are
designed for editing the three different formats. The command `M-x
tex-mode' looks at the contents of the buffer to determine whether the
contents appear to be either LaTeX input or SliTeX input; if so, it
selects the appropriate mode. If the file contents do not appear to be
LaTeX or SliTeX, it selects Plain TeX mode. If the contents are
insufficient to determine this, the variable `tex-default-mode'
controls which mode is used.
When `M-x tex-mode' does not guess right, you can use the commands
`M-x plain-tex-mode', `M-x latex-mode', and `M-x slitex-mode' to select
explicitly the particular variants of TeX mode.
TeX Editing Commands
--------------------
Here are the special commands provided in TeX mode for editing the
text of the file.
`"'
Insert, according to context, either ```' or `"' or `'''
(`tex-insert-quote').
`C-j'
Insert a paragraph break (two newlines) and check the previous
paragraph for unbalanced braces or dollar signs
(`tex-terminate-paragraph').
`M-x tex-validate-region'
Check each paragraph in the region for unbalanced braces or dollar
signs.
`C-c {'
Insert `{}' and position point between them (`tex-insert-braces').
`C-c }'
Move forward past the next unmatched close brace (`up-list').
In TeX, the character `"' is not normally used; we use ```' to start
a quotation and `''' to end one. To make editing easier under this
formatting convention, TeX mode overrides the normal meaning of the key
`"' with a command that inserts a pair of single-quotes or backquotes
(`tex-insert-quote'). To be precise, this command inserts ```' after
whitespace or an open brace, `"' after a backslash, and `''' after any
other character.
If you need the character `"' itself in unusual contexts, use `C-q'
to insert it. Also, `"' with a numeric argument always inserts that
number of `"' characters. You can turn off the feature of `"'
expansion by eliminating that binding in the local map (*note Key
Bindings::.).
In TeX mode, `$' has a special syntax code which attempts to
understand the way TeX math mode delimiters match. When you insert a
`$' that is meant to exit math mode, the position of the matching `$'
that entered math mode is displayed for a second. This is the same
feature that displays the open brace that matches a close brace that is
inserted. However, there is no way to tell whether a `$' enters math
mode or leaves it; so when you insert a `$' that enters math mode, the
previous `$' position is shown as if it were a match, even though they
are actually unrelated.
TeX uses braces as delimiters that must match. Some users prefer to
keep braces balanced at all times, rather than inserting them singly.
Use `C-c {' (`tex-insert-braces') to insert a pair of braces. It
leaves point between the two braces so you can insert the text that
belongs inside. Afterward, use the command `C-c }' (`up-list') to move
forward past the close brace.
There are two commands for checking the matching of braces. `C-j'
(`tex-terminate-paragraph') checks the paragraph before point, and
inserts two newlines to start a new paragraph. It prints a message in
the echo area if any mismatch is found. `M-x tex-validate-region'
checks a region, paragraph by paragraph. The errors are listed in the
`*Occur*' buffer, and you can use `C-c C-c' or `Mouse-2' in that buffer
to go to a particular mismatch.
Note that Emacs commands count square brackets and parentheses in
TeX mode, not just braces. This is not strictly correct for the
purpose of checking TeX syntax. However, parentheses and square
brackets are likely to be used in text as matching delimiters and it is
useful for the various motion commands and automatic match display to
work with them.
LaTeX Editing Commands
----------------------
LaTeX mode, and its variant, SliTeX mode, provide a few extra
features not applicable to plain TeX.
`C-c C-o'
Insert `\begin' and `\end' for LaTeX block and position point on a
line between them (`tex-latex-block').
`C-c C-e'
Close the innermost LaTeX block not yet closed
(`tex-close-latex-block').
In LaTeX input, `\begin' and `\end' commands are used to group
blocks of text. To insert a `\begin' and a matching `\end' (on a new
line following the `\begin'), use `C-c C-o' (`tex-latex-block'). A
blank line is inserted between the two, and point is left there. You
can use completion when you enter the block type; to specify additional
block type names beyond the standard list, set the variable
`latex-block-names'. For example, here's how to add `theorem',
`corollary', and `proof':
(setq latex-block-names '("theorem" "corollary" "proof"))
In LaTeX input, `\begin' and `\end' commands must balance. You can
use `C-c C-e' (`tex-close-latex-block') to insert automatically a
matching `\end' to match the last unmatched `\begin'. It indents the
`\end' to match the corresponding `\begin'. It inserts a newline after
`\end' if point is at the beginning of a line.
TeX Printing Commands
---------------------
You can invoke TeX as an inferior of Emacs on either the entire
contents of the buffer or just a region at a time. Running TeX in this
way on just one chapter is a good way to see what your changes look
like without taking the time to format the entire file.
`C-c C-r'
Invoke TeX on the current region, together with the buffer's header
(`tex-region').
`C-c C-b'
Invoke TeX on the entire current buffer (`tex-buffer').
`C-c <TAB>'
Invoke BibTeX on the current file (`tex-bibtex-file').
`C-c C-f'
Invoke TeX on the current file (`tex-file').
`C-c C-l'
Recenter the window showing output from the inferior TeX so that
the last line can be seen (`tex-recenter-output-buffer').
`C-c C-k'
Kill the TeX subprocess (`tex-kill-job').
`C-c C-p'
Print the output from the last `C-c C-r', `C-c C-b', or `C-c C-f'
command (`tex-print').
`C-c C-v'
Preview the output from the last `C-c C-r', `C-c C-b', or `C-c
C-f' command (`tex-view').
`C-c C-q'
Show the printer queue (`tex-show-print-queue').
You can pass the current buffer through an inferior TeX by means of
`C-c C-b' (`tex-buffer'). The formatted output appears in a temporary
file; to print it, type `C-c C-p' (`tex-print'). Afterward, you can
use `C-c C-q' (`tex-show-print-queue') to view the progress of your
output towards being printed. If your terminal has the ability to
display TeX output files, you can preview the output on the terminal
with `C-c C-v' (`tex-view').
You can specify the directory to use for running TeX by setting the
variable `tex-directory'. `"."' is the default value. If your
environment variable `TEXINPUTS' contains relative directory names, or
if your files contains `\input' commands with relative file names, then
`tex-directory' *must* be `"."' or you will get the wrong results.
Otherwise, it is safe to specify some other directory, such as `"/tmp"'.
If you want to specify which shell commands are used in the inferior
TeX, you can do so by setting the values of the variables
`tex-run-command', `latex-run-command', `slitex-run-command',
`tex-dvi-print-command', `tex-dvi-view-command', and
`tex-show-queue-command'. You *must* set the value of
`tex-dvi-view-command' for your particular terminal; this variable has
no default value. The other variables have default values that may (or
may not) be appropriate for your system.
Normally, the file name given to these commands comes at the end of
the command string; for example, `latex FILENAME'. In some cases,
however, the file name needs to be embedded in the command; an example
is when you need to provide the file name as an argument to one command
whose output is piped to another. You can specify where to put the
file name with `*' in the command string. For example,
(setq tex-dvi-print-command "dvips -f * | lpr")
The terminal output from TeX, including any error messages, appears
in a buffer called `*tex-shell*'. If TeX gets an error, you can switch
to this buffer and feed it input (this works as in Shell mode; *note
Interactive Shell::.). Without switching to this buffer you can scroll
it so that its last line is visible by typing `C-c C-l'.
Type `C-c C-k' (`tex-kill-job') to kill the TeX process if you see
that its output is no longer useful. Using `C-c C-b' or `C-c C-r' also
kills any TeX process still running.
You can also pass an arbitrary region through an inferior TeX by
typing `C-c C-r' (`tex-region'). This is tricky, however, because most
files of TeX input contain commands at the beginning to set parameters
and define macros, without which no later part of the file will format
correctly. To solve this problem, `C-c C-r' allows you to designate a
part of the file as containing essential commands; it is included before
the specified region as part of the input to TeX. The designated part
of the file is called the "header".
To indicate the bounds of the header in Plain TeX mode, you insert
two special strings in the file. Insert `%**start of header' before the
header, and `%**end of header' after it. Each string must appear
entirely on one line, but there may be other text on the line before or
after. The lines containing the two strings are included in the header.
If `%**start of header' does not appear within the first 100 lines of
the buffer, `C-c C-r' assumes that there is no header.
In LaTeX mode, the header begins with `\documentstyle' and ends with
`\begin{document}'. These are commands that LaTeX requires you to use
in any case, so nothing special needs to be done to identify the header.
The commands (`tex-buffer') and (`tex-region') do all of their work
in a temporary directory, and do not have available any of the auxiliary
files needed by TeX for cross-references; these commands are generally
not suitable for running the final copy in which all of the
cross-references need to be correct.
When you want the auxiliary files for cross references, use `C-c
C-f' (`tex-file') which runs TeX on the current buffer's file, in that
file's directory. Before running TeX, it offers to save any modified
buffers. Generally, you need to use (`tex-file') twice to get the
cross-references right.
The value of the variable `tex-start-options-string' specifies
options for the TeX run. The default value causes TeX to run in
nonstopmode. To run TeX interactively, set the variable to `""'.
Large TeX documents are often split into several files--one main
file, plus subfiles. Running TeX on a subfile typically does not work;
you have to run it on the main file. In order to make `tex-file'
useful when you are editing a subfile, you can set the variable
`tex-main-file' to the name of the main file. Then `tex-file' runs TeX
on that file.
The most convenient way to use `tex-main-file' is to specify it in a
local variable list in each of the subfiles. *Note File Variables::.
For LaTeX files, you can use BibTeX to process the auxiliary file
for the current buffer's file. BibTeX looks up bibliographic citations
in a data base and prepares the cited references for the bibliography
section. The command `C-c TAB' (`tex-bibtex-file') runs the shell
command (`tex-bibtex-command') to produce a `.bbl' file for the current
buffer's file. Generally, you need to do `C-c C-f' (`tex-file') once
to generate the `.aux' file, then do `C-c TAB' (`tex-bibtex-file'), and
then repeat `C-c C-f' (`tex-file') twice more to get the
cross-references correct.
Entering any kind of TeX mode runs the hooks `text-mode-hook' and
`tex-mode-hook'. Then it runs either `plain-tex-mode-hook' or
`latex-mode-hook', whichever is appropriate. For SliTeX files, it
calls `slitex-mode-hook'. Starting the TeX shell runs the hook
`tex-shell-hook'. *Note Hooks::.
Nroff Mode
==========
Nroff mode is a mode like Text mode but modified to handle nroff
commands present in the text. Invoke `M-x nroff-mode' to enter this
mode. It differs from Text mode in only a few ways. All nroff command
lines are considered paragraph separators, so that filling will never
garble the nroff commands. Pages are separated by `.bp' commands.
Comments start with backslash-doublequote. Also, three special
commands are provided that are not in Text mode:
`M-n'
Move to the beginning of the next line that isn't an nroff command
(`forward-text-line'). An argument is a repeat count.
`M-p'
Like `M-n' but move up (`backward-text-line').
`M-?'
Prints in the echo area the number of text lines (lines that are
not nroff commands) in the region (`count-text-lines').
The other feature of Nroff mode is that you can turn on Electric
Nroff mode. This is a minor mode that you can turn on or off with `M-x
electric-nroff-mode' (*note Minor Modes::.). When the mode is on, each
time you use <RET> to end a line that contains an nroff command that
opens a kind of grouping, the matching nroff command to close that
grouping is automatically inserted on the following line. For example,
if you are at the beginning of a line and type `. ( b <RET>', this
inserts the matching command `.)b' on a new line following point.
If you use Outline minor mode with Nroff mode (*note Outline
Mode::.), heading lines are lines of the form `.H' followed by a number
(the header level).
Entering Nroff mode runs the hook `text-mode-hook', followed by the
hook `nroff-mode-hook' (*note Hooks::.).
Editing Formatted Text
======================
"Enriched mode" is a minor mode for editing files that contain
formatted text in WYSIWYG fashion, as in a word processor. Currently,
formatted text in Enriched mode can specify fonts, colors, underlining,
margins, and types of filling and justification. In the future, we plan
to implement other formatting features as well.
Enriched mode is a minor mode (*note Minor Modes::.). Typically it
is used in conjunction with Text mode (*note Text Mode::.). However,
you can also use it with other major modes such as Outline mode and
Paragraph-Indent Text mode.
Potentially, Emacs can store formatted text files in various file
formats. Currently, only one format is implemented: "text/enriched"
format, which is defined by the MIME protocol. *Note Format
Conversion: (elisp)Format Conversion, for details of how Emacs
recognizes and converts file formats.
The Emacs distribution contains a formatted text file that can serve
as an example. Its name is `etc/enriched.doc'. It contains samples
illustrating all the features described in this section. It also
contains a list of ideas for future enhancements.
Requesting to Edit Formatted Text
---------------------------------
Whenever you visit a file that Emacs saved in the text/enriched
format, Emacs automatically converts the formatting information in the
file into Emacs's own internal format (text properties), and turns on
Enriched mode.
To create a new file of formatted text, first visit the nonexistent
file, then type `M-x enriched-mode' before you start inserting text.
This command turns on Enriched mode. Do this before you begin inserting
text, to ensure that the text you insert is handled properly.
More generally, the command `enriched-mode' turns Enriched mode on
if it was off, and off if it was on. With a prefix argument, this
command turns Enriched mode on if the argument is positive, and turns
the mode off otherwise.
When you save a buffer while Enriched mode is enabled in it, Emacs
automatically converts the text to text/enriched format while writing it
into the file. When you visit the file again, Emacs will automatically
recognize the format, reconvert the text, and turn on Enriched mode
again.
Normally, after visiting a file in text/enriched format, Emacs
refills each paragraph to fit the specified right margin. You can turn
off this refilling, to save time, by setting the variable
`enriched-fill-after-visiting' to `nil' or to `ask'.
However, when visiting a file that was saved from Enriched mode,
there is no need for refilling, because Emacs saves the right margin
settings along with the text.
You can add annotations for saving additional text properties, which
Emacs normally does not save, by adding to `enriched-translations'.
Note that the text/enriched standard requires any non-standard
annotations to have names starting with `x-', as in `x-read-only'.
This ensures that they will not conflict with standard annotations that
may be added later.
Hard and Soft Newlines
----------------------
In formatted text, Emacs distinguishes between two different kinds of
newlines, "hard" newlines and "soft" newlines.
Hard newlines are used to separate paragraphs, or items in a list, or
anywhere that there should always be a line break regardless of the
margins. The <RET> command (`newline') and `C-o' (`open-line') insert
hard newlines.
Soft newlines are used to make text fit between the margins. All the
fill commands, including Auto Fill, insert soft newlines--and they
delete only soft newlines.
Although hard and soft newlines look the same, it is important to
bear the difference in mind. Do not use <RET> to break lines in the
middle of filled paragraphs, or else you will get hard newlines that are
barriers to further filling. Instead, let Auto Fill mode break lines,
so that if the text or the margins change, Emacs can refill the lines
properly. *Note Auto Fill::.
On the other hand, in tables and lists, where the lines should always
remain as you type them, you can use <RET> to end lines. For these
lines, you may also want to set the justification style to `unfilled'.
*Note Format Justification::.
Editing Format Information
--------------------------
There are two ways to alter the formatting information for a
formatted text file: with keyboard commands, and with the mouse.
The easiest way to add properties to your document is by using the
Text Properties menu. You can get to this menu in two ways: from the
Edit menu in the menu bar, or with `C-mouse-2' (hold the <CTRL> key and
press the middle mouse button).
Most of the items in the Text Properties menu lead to other submenus.
These are described in the sections that follow. Some items run
commands directly:
`Remove Properties'
Delete from the region all the text properties that the Text
Properties menu works with (`facemenu-remove-props').
`Remove All'
Delete *all* text properties from the region
(`facemenu-remove-all').
`List Properties'
List all the text properties of the character following point
(`list-text-properties-at').
`Display Faces'
Display a list of all the defined faces.
`Display Colors'
Display a list of all the defined colors.
Faces in Formatted Text
-----------------------
The Faces submenu lists various Emacs faces including `bold',
`italic', and `underline'. Selecting one of these adds the chosen face
to the region. *Note Faces::. You can also specify a face with these
keyboard commands:
`M-g d'
Set the region, or the next inserted character, to the `default'
face (`facemenu-set-default').
`M-g b'
Set the region, or the next inserted character, to the `bold' face
(`facemenu-set-bold').
`M-g i'
Set the region, or the next inserted character, to the `italic'
face (`facemenu-set-italic').
`M-g l'
Set the region, or the next inserted character, to the
`bold-italic' face (`facemenu-set-bold-italic').
`M-g u'
Set the region, or the next inserted character, to the `underline'
face (`facemenu-set-underline').
`M-g o FACE <RET>'
Set the region, or the next inserted character, to the face FACE
(`facemenu-set-face').
If you use these commands with a prefix argument--or, in Transient
Mark mode, if the region is not active--then these commands specify a
face to use for your next self-inserting input. *Note Transient
Mark::. This applies to both the keyboard commands and the menu
commands.
Enriched mode defines two additional faces: `excerpt' and `fixed'.
These correspond to codes used in the text/enriched file format.
The `excerpt' face is intended for quotations. This face is the
same as `italic' unless you customize it (*note Face Customization::.).
The `fixed' face is meant to say, "Use a fixed-width font for this
part of the text." Emacs currently supports only fixed-width fonts;
therefore, the `fixed' annotation is not necessary now. However, we
plan to support variable width fonts in future Emacs versions, and
other systems that display text/enriched format may not use a
fixed-width font as the default. So if you specifically want a certain
part of the text to use a fixed-width font, you should specify the
`fixed' face for that part.
The `fixed' face is normally defined to use a different font from
the default. However, different systems have different fonts installed,
so you may need to customize this.
If your terminal cannot display different faces, you will not be able
to see them, but you can still edit documents containing faces. You can
even add faces and colors to documents. They will be visible when the
file is viewed on a terminal that can display them.
Colors in Formatted Text
------------------------
You can specify foreground and background colors for portions of the
text. There is a menu for specifying the foreground color and a menu
for specifying the background color. Each color menu lists all the
colors that you have used in Enriched mode in the current Emacs session.
If you specify a color with a prefix argument--or, in Transient Mark
mode, if the region is not active--then it applies to your next
self-inserting input. *Note Transient Mark::. Otherwise, the command
applies to the region.
Each color menu contains one additional item: `Other'. You can use
this item to specify a color that is not listed in the menu; it reads
the color name with the minibuffer. To display list of available colors
and their names, use the `Display Colors' menu item in the Text
Properties menu (*note Editing Format Info::.).
Any color that you specify in this way, or that is mentioned in a
formatted text file that you read in, is added to both color menus for
the duration of the Emacs session.
There are no key bindings for specifying colors, but you can do so
with the extended commands `M-x facemenu-set-foreground' and `M-x
facemenu-set-background'. Both of these commands read the name of the
color with the minibuffer.
Indentation in Formatted Text
-----------------------------
When editing formatted text, you can specify different amounts of
indentation for the right or left margin of an entire paragraph or a
part of a paragraph. The margins you specify automatically affect the
Emacs fill commands (*note Filling::.) and line-breaking commands.
The Indentation submenu provides a convenient interface for
specifying these properties. The submenu contains four items:
`Indent More'
Indent the region by 4 columns (`increase-left-margin'). In
Enriched mode, this command is also available on `C-x <TAB>'; if
you supply a numeric argument, that says how many columns to add
to the margin (a negative argument reduces the number of columns).
`Indent Less'
Remove 4 columns of indentation from the region.
`Indent Right More'
Make the text narrower by indenting 4 columns at the right margin.
`Indent Right Less'
Remove 4 columns of indentation from the right margin.
You can use these commands repeatedly to increase or decrease the
indentation.
The most common way to use these commands is to change the
indentation of an entire paragraph. However, that is not the only use.
You can change the margins at any point; the new values take effect at
the end of the line (for right margins) or the beginning of the next
line (for left margins).
This makes it possible to format paragraphs with "hanging indents",
which means that the first line is indented less than subsequent lines.
To set up a hanging indent, increase the indentation of the region
starting after the first word of the paragraph and running until the end
of the paragraph.
Indenting the first line of a paragraph is easier. Set the margin
for the whole paragraph where you want it to be for the body of the
paragraph, then indent the first line by inserting extra spaces or tabs.
Sometimes, as a result of editing, the filling of a paragraph becomes
messed up--parts of the paragraph may extend past the left or right
margins. When this happens, use `M-q' (`fill-paragraph') to refill the
paragraph.
The variable `standard-indent' specifies how many columns these
commands should add to or subtract from the indentation. The default
value is 4. The overall default right margin for Enriched mode is
controlled by the variable `fill-column', as usual.
The fill prefix, if any, works in addition to the specified paragraph
indentation: `C-x .' does not include the specified indentation's
whitespace in the new value for the fill prefix, and the fill commands
look for the fill prefix after the indentation on each line. *Note
Fill Prefix::.
Justification in Formatted Text
-------------------------------
When editing formatted text, you can specify various styles of
justification for a paragraph. The style you specify automatically
affects the Emacs fill commands.
The Justification submenu provides a convenient interface for
specifying the style. The submenu contains five items:
`Flush Left'
This is the most common style of justification (at least for
English). Lines are aligned at the left margin but left uneven at
the right.
`Flush Right'
This aligns each line with the right margin. Spaces and tabs are
added on the left, if necessary, to make lines line up on the
right.
`Full'
This justifies the text, aligning both edges of each line.
Justified text looks very nice in a printed book, where the spaces
can all be adjusted equally, but it does not look as nice with a
fixed-width font on the screen. Perhaps a future version of Emacs
will be able to adjust the width of spaces in a line to achieve
elegant justification.
`Center'
This centers every line between the current margins.
`None'
This turns off filling entirely. Each line will remain as you
wrote it; the fill and auto-fill functions will have no effect on
text which has this setting. You can, however, still indent the
left margin. In unfilled regions, all newlines are treated as
hard newlines (*note Hard and Soft Newlines::.) .
In Enriched mode, you can also specify justification from the
keyboard using the `M-j' prefix character:
`M-j l'
Make the region left-filled (`set-justification-left').
`M-j r'
Make the region right-filled (`set-justification-right').
`M-j f'
Make the region fully-justified (`set-justification-full').
`M-j c'
`M-S'
Make the region centered (`set-justification-center').
`M-j u'
Make the region unfilled (`set-justification-none').
Justification styles apply to entire paragraphs. All the
justification-changing commands operate on the paragraph containing
point, or, if the region is active, on all paragraphs which overlap the
region.
The default justification style is specified by the variable
`default-justification'. Its value should be one of the symbols
`left', `right', `full', `center', or `none'.
Setting Other Text Properties
-----------------------------
The Other Properties menu lets you add or remove three other useful
text properties: `read-only', `invisible' and `intangible'. The
`intangible' property disallows moving point within the text, the
`invisible' text property hides text from display, and the `read-only'
property disallows alteration of the text.
Each of these special properties has a menu item to add it to the
region. The last menu item, `Remove Special', removes all of these
special properties from the text in the region.
Currently, the `invisible' and `intangible' properties are *not*
saved in the text/enriched format. The `read-only' property is saved,
but it is not a standard part of the text/enriched format, so other
editors may not respect it.
Forcing Enriched Mode
---------------------
Normally, Emacs knows when you are editing formatted text because it
recognizes the special annotations used in the file that you visited.
However, there are situations in which you must take special actions to
convert file contents or turn on Enriched mode:
* When you visit a file that was created with some other editor,
Emacs may not recognize the file as being in the text/enriched
format. In this case, when you visit the file you will see the
formatting commands rather than the formatted text. Type `M-x
format-decode-buffer' to translate it.
* When you *insert* a file into a buffer, rather than visiting it.
Emacs does the necessary conversions on the text which you insert,
but it does not enable Enriched mode. If you wish to do that,
type `M-x enriched-mode'.
The command `format-decode-buffer' translates text in various
formats into Emacs's internal format. It asks you to specify the format
to translate from; however, normally you can type just <RET>, which
tells Emacs to guess the format.
If you wish to look at text/enriched file in its raw form, as a
sequence of characters rather than as formatted text, use the `M-x
find-file-literally' command. This visits a file, like `find-file',
but does not do format conversion. It also inhibits character code
conversion (*note Coding Systems::.) and automatic uncompression (*note
Compressed Files::.). To disable format conversion but allow character
code conversion and/or automatic uncompression if appropriate, use
`format-find-file' with suitable arguments.
Editing Programs
****************
Emacs has many commands designed to understand the syntax of
programming languages such as Lisp and C. These commands can
* Move over or kill balanced expressions or "sexps" (*note Lists::.).
* Move over or mark top-level expressions--"defuns", in Lisp;
functions, in C (*note Defuns::.).
* Show how parentheses balance (*note Matching::.).
* Insert, kill or align comments (*note Comments::.).
* Follow the usual indentation conventions of the language (*note
Program Indent::.).
The commands for words, sentences and paragraphs are very useful in
editing code even though their canonical application is for editing
human language text. Most symbols contain words (*note Words::.);
sentences can be found in strings and comments (*note Sentences::.).
Paragraphs per se don't exist in code, but the paragraph commands are
useful anyway, because programming language major modes define
paragraphs to begin and end at blank lines (*note Paragraphs::.).
Judicious use of blank lines to make the program clearer will also
provide useful chunks of text for the paragraph commands to work on.
The selective display feature is useful for looking at the overall
structure of a function (*note Selective Display::.). This feature
causes only the lines that are indented less than a specified amount to
appear on the screen.
Major Modes for Programming Languages
=====================================
Emacs also has major modes for the programming languages Lisp, Scheme
(a variant of Lisp), Awk, C, C++, Fortran, Icon, Java, Objective-C,
Pascal, Perl, Pike, CORBA IDL, and Tcl. There is also a major mode for
makefiles, called Makefile mode. An second alternative mode for Perl is
called CPerl mode.
Ideally, a major mode should be implemented for each programming
language that you might want to edit with Emacs; but often the mode for
one language can serve for other syntactically similar languages. The
language modes that exist are those that someone decided to take the
trouble to write.
There are several forms of Lisp mode, which differ in the way they
interface to Lisp execution. *Note Executing Lisp::.
Each of the programming language major modes defines the <TAB> key
to run an indentation function that knows the indentation conventions of
that language and updates the current line's indentation accordingly.
For example, in C mode <TAB> is bound to `c-indent-line'. `C-j' is
normally defined to do <RET> followed by <TAB>; thus, it too indents in
a mode-specific fashion.
In most programming languages, indentation is likely to vary from
line to line. So the major modes for those languages rebind <DEL> to
treat a tab as if it were the equivalent number of spaces (using the
command `backward-delete-char-untabify'). This makes it possible to
rub out indentation one column at a time without worrying whether it is
made up of spaces or tabs. Use `C-b C-d' to delete a tab character
before point, in these modes.
Programming language modes define paragraphs to be separated only by
blank lines, so that the paragraph commands remain useful. Auto Fill
mode, if enabled in a programming language major mode, indents the new
lines which it creates.
Turning on a major mode runs a normal hook called the "mode hook",
which is the value of a Lisp variable. Each major mode has a mode hook,
and the hook's name is always made from the mode command's name by
adding `-hook'. For example, turning on C mode runs the hook
`c-mode-hook', while turning on Lisp mode runs the hook
`lisp-mode-hook'. *Note Hooks::.
Lists and Sexps
===============
By convention, Emacs keys for dealing with balanced expressions are
usually Control-Meta characters. They tend to be analogous in function
to their Control and Meta equivalents. These commands are usually
thought of as pertaining to expressions in programming languages, but
can be useful with any language in which some sort of parentheses exist
(including human languages).
These commands fall into two classes. Some deal only with "lists"
(parenthetical groupings). They see nothing except parentheses,
brackets, braces (whichever ones must balance in the language you are
working with), and escape characters that might be used to quote those.
The other commands deal with expressions or "sexps". The word `sexp'
is derived from "s-expression", the ancient term for an expression in
Lisp. But in Emacs, the notion of `sexp' is not limited to Lisp. It
refers to an expression in whatever language your program is written in.
Each programming language has its own major mode, which customizes the
syntax tables so that expressions in that language count as sexps.
Sexps typically include symbols, numbers, and string constants, as
well as anything contained in parentheses, brackets or braces.
In languages that use prefix and infix operators, such as C, it is
not possible for all expressions to be sexps. For example, C mode does
not recognize `foo + bar' as a sexp, even though it *is* a C expression;
it recognizes `foo' as one sexp and `bar' as another, with the `+' as
punctuation between them. This is a fundamental ambiguity: both `foo +
bar' and `foo' are legitimate choices for the sexp to move over if
point is at the `f'. Note that `(foo + bar)' is a single sexp in C
mode.
Some languages have obscure forms of expression syntax that nobody
has bothered to make Emacs understand properly.
List And Sexp Commands
======================
`C-M-f'
Move forward over a sexp (`forward-sexp').
`C-M-b'
Move backward over a sexp (`backward-sexp').
`C-M-k'
Kill sexp forward (`kill-sexp').
`C-M-<DEL>'
Kill sexp backward (`backward-kill-sexp').
`C-M-u'
Move up and backward in list structure (`backward-up-list').
`C-M-d'
Move down and forward in list structure (`down-list').
`C-M-n'
Move forward over a list (`forward-list').
`C-M-p'
Move backward over a list (`backward-list').
`C-M-t'
Transpose expressions (`transpose-sexps').
`C-M-@'
Put mark after following expression (`mark-sexp').
To move forward over a sexp, use `C-M-f' (`forward-sexp'). If the
first significant character after point is an opening delimiter (`(' in
Lisp; `(', `[' or `{' in C), `C-M-f' moves past the matching closing
delimiter. If the character begins a symbol, string, or number,
`C-M-f' moves over that.
The command `C-M-b' (`backward-sexp') moves backward over a sexp.
The detailed rules are like those above for `C-M-f', but with
directions reversed. If there are any prefix characters (single-quote,
backquote and comma, in Lisp) preceding the sexp, `C-M-b' moves back
over them as well. The sexp commands move across comments as if they
were whitespace in most modes.
`C-M-f' or `C-M-b' with an argument repeats that operation the
specified number of times; with a negative argument, it moves in the
opposite direction.
Killing a whole sexp can be done with `C-M-k' (`kill-sexp') or
`C-M-<DEL>' (`backward-kill-sexp'). `C-M-k' kills the characters that
`C-M-f' would move over, and `C-M-<DEL>' kills the characters that
`C-M-b' would move over.
The "list commands" move over lists, as the sexp commands do, but
skip blithely over any number of other kinds of sexps (symbols,
strings, etc.). They are `C-M-n' (`forward-list') and `C-M-p'
(`backward-list'). The main reason they are useful is that they
usually ignore comments (since the comments usually do not contain any
lists).
`C-M-n' and `C-M-p' stay at the same level in parentheses, when
that's possible. To move *up* one (or N) levels, use `C-M-u'
(`backward-up-list'). `C-M-u' moves backward up past one unmatched
opening delimiter. A positive argument serves as a repeat count; a
negative argument reverses direction of motion and also requests
repetition, so it moves forward and up one or more levels.
To move *down* in list structure, use `C-M-d' (`down-list'). In
Lisp mode, where `(' is the only opening delimiter, this is nearly the
same as searching for a `('. An argument specifies the number of
levels of parentheses to go down.
A somewhat random-sounding command which is nevertheless handy is
`C-M-t' (`transpose-sexps'), which drags the previous sexp across the
next one. An argument serves as a repeat count, and a negative
argument drags backwards (thus canceling out the effect of `C-M-t' with
a positive argument). An argument of zero, rather than doing nothing,
transposes the sexps ending after point and the mark.
To set the region around the next sexp in the buffer, use `C-M-@'
(`mark-sexp'), which sets mark at the same place that `C-M-f' would
move to. `C-M-@' takes arguments like `C-M-f'. In particular, a
negative argument is useful for putting the mark at the beginning of
the previous sexp.
The list and sexp commands' understanding of syntax is completely
controlled by the syntax table. Any character can, for example, be
declared to be an opening delimiter and act like an open parenthesis.
*Note Syntax::.
Defuns
======
In Emacs, a parenthetical grouping at the top level in the buffer is
called a "defun". The name derives from the fact that most top-level
lists in a Lisp file are instances of the special form `defun', but any
top-level parenthetical grouping counts as a defun in Emacs parlance
regardless of what its contents are, and regardless of the programming
language in use. For example, in C, the body of a function definition
is a defun.
`C-M-a'
Move to beginning of current or preceding defun
(`beginning-of-defun').
`C-M-e'
Move to end of current or following defun (`end-of-defun').
`C-M-h'
Put region around whole current or following defun (`mark-defun').
The commands to move to the beginning and end of the current defun
are `C-M-a' (`beginning-of-defun') and `C-M-e' (`end-of-defun').
If you wish to operate on the current defun, use `C-M-h'
(`mark-defun') which puts point at the beginning and mark at the end of
the current or next defun. For example, this is the easiest way to get
ready to move the defun to a different place in the text. In C mode,
`C-M-h' runs the function `c-mark-function', which is almost the same
as `mark-defun'; the difference is that it backs up over the argument
declarations, function name and returned data type so that the entire C
function is inside the region. *Note Marking Objects::.
Emacs assumes that any open-parenthesis found in the leftmost column
is the start of a defun. Therefore, *never put an open-parenthesis at
the left margin in a Lisp file unless it is the start of a top-level
list. Never put an open-brace or other opening delimiter at the
beginning of a line of C code unless it starts the body of a function.*
The most likely problem case is when you want an opening delimiter at
the start of a line inside a string. To avoid trouble, put an escape
character (`\', in C and Emacs Lisp, `/' in some other Lisp dialects)
before the opening delimiter. It will not affect the contents of the
string.
In the remotest past, the original Emacs found defuns by moving
upward a level of parentheses until there were no more levels to go up.
This always required scanning all the way back to the beginning of the
buffer, even for a small function. To speed up the operation, Emacs
was changed to assume that any `(' (or other character assigned the
syntactic class of opening-delimiter) at the left margin is the start
of a defun. This heuristic is nearly always right and avoids the
costly scan; however, it mandates the convention described above.
Indentation for Programs
========================
The best way to keep a program properly indented is to use Emacs to
reindent it as you change it. Emacs has commands to indent properly
either a single line, a specified number of lines, or all of the lines
inside a single parenthetical grouping.
Emacs also provides a Lisp pretty-printer in the library `pp'. This
program reformats a Lisp object with indentation chosen to look nice.
Basic Program Indentation Commands
----------------------------------
`<TAB>'
Adjust indentation of current line.
`C-j'
Equivalent to <RET> followed by <TAB> (`newline-and-indent').
The basic indentation command is <TAB>, which gives the current line
the correct indentation as determined from the previous lines. The
function that <TAB> runs depends on the major mode; it is
`lisp-indent-line' in Lisp mode, `c-indent-line' in C mode, etc. These
functions understand different syntaxes for different languages, but
they all do about the same thing. <TAB> in any programming-language
major mode inserts or deletes whitespace at the beginning of the
current line, independent of where point is in the line. If point is
inside the whitespace at the beginning of the line, <TAB> leaves it at
the end of that whitespace; otherwise, <TAB> leaves point fixed with
respect to the characters around it.
Use `C-q <TAB>' to insert a tab at point.
When entering lines of new code, use `C-j' (`newline-and-indent'),
which is equivalent to a <RET> followed by a <TAB>. `C-j' creates a
blank line and then gives it the appropriate indentation.
<TAB> indents the second and following lines of the body of a
parenthetical grouping each under the preceding one; therefore, if you
alter one line's indentation to be nonstandard, the lines below will
tend to follow it. This behavior is convenient in cases where you have
overridden the standard result of <TAB> because you find it unaesthetic
for a particular line.
Remember that an open-parenthesis, open-brace or other opening
delimiter at the left margin is assumed by Emacs (including the
indentation routines) to be the start of a function. Therefore, you
must never have an opening delimiter in column zero that is not the
beginning of a function, not even inside a string. This restriction is
vital for making the indentation commands fast; you must simply accept
it. *Note Defuns::, for more information on this.
Indenting Several Lines
-----------------------
When you wish to reindent several lines of code which have been
altered or moved to a different level in the list structure, you have
several commands available.
`C-M-q'
Reindent all the lines within one list (`indent-sexp').
`C-u <TAB>'
Shift an entire list rigidly sideways so that its first line is
properly indented.
`C-M-\'
Reindent all lines in the region (`indent-region').
You can reindent the contents of a single list by positioning point
before the beginning of it and typing `C-M-q' (`indent-sexp' in Lisp
mode, `c-indent-exp' in C mode; also bound to other suitable commands
in other modes). The indentation of the line the sexp starts on is not
changed; therefore, only the relative indentation within the list, and
not its position, is changed. To correct the position as well, type a
<TAB> before the `C-M-q'.
If the relative indentation within a list is correct but the
indentation of its first line is not, go to that line and type `C-u
<TAB>'. <TAB> with a numeric argument reindents the current line as
usual, then reindents by the same amount all the lines in the grouping
starting on the current line. In other words, it reindents the whole
grouping rigidly as a unit. It is clever, though, and does not alter
lines that start inside strings, or C preprocessor lines when in C mode.
Another way to specify the range to be reindented is with the region.
The command `C-M-\' (`indent-region') applies <TAB> to every line whose
first character is between point and mark.
Customizing Lisp Indentation
----------------------------
The indentation pattern for a Lisp expression can depend on the
function called by the expression. For each Lisp function, you can
choose among several predefined patterns of indentation, or define an
arbitrary one with a Lisp program.
The standard pattern of indentation is as follows: the second line
of the expression is indented under the first argument, if that is on
the same line as the beginning of the expression; otherwise, the second
line is indented underneath the function name. Each following line is
indented under the previous line whose nesting depth is the same.
If the variable `lisp-indent-offset' is non-`nil', it overrides the
usual indentation pattern for the second line of an expression, so that
such lines are always indented `lisp-indent-offset' more columns than
the containing list.
The standard pattern is overridden for certain functions. Functions
whose names start with `def' always indent the second line by
`lisp-body-indent' extra columns beyond the open-parenthesis starting
the expression.
The standard pattern can be overridden in various ways for individual
functions, according to the `lisp-indent-function' property of the
function name. There are four possibilities for this property:
`nil'
This is the same as no property; the standard indentation pattern
is used.
`defun'
The pattern used for function names that start with `def' is used
for this function also.
a number, NUMBER
The first NUMBER arguments of the function are "distinguished"
arguments; the rest are considered the "body" of the expression.
A line in the expression is indented according to whether the
first argument on it is distinguished or not. If the argument is
part of the body, the line is indented `lisp-body-indent' more
columns than the open-parenthesis starting the containing
expression. If the argument is distinguished and is either the
first or second argument, it is indented *twice* that many extra
columns. If the argument is distinguished and not the first or
second argument, the standard pattern is followed for that line.
a symbol, SYMBOL
SYMBOL should be a function name; that function is called to
calculate the indentation of a line within this expression. The
function receives two arguments:
STATE
The value returned by `parse-partial-sexp' (a Lisp primitive
for indentation and nesting computation) when it parses up to
the beginning of this line.
POS
The position at which the line being indented begins.
It should return either a number, which is the number of columns of
indentation for that line, or a list whose car is such a number.
The difference between returning a number and returning a list is
that a number says that all following lines at the same nesting
level should be indented just like this one; a list says that
following lines might call for different indentations. This makes
a difference when the indentation is being computed by `C-M-q'; if
the value is a number, `C-M-q' need not recalculate indentation
for the following lines until the end of the list.
Commands for C Indentation
--------------------------
Here are the commands for indentation in C mode and related modes:
`C-c C-q'
Reindent the current top-level function definition or aggregate
type declaration (`c-indent-defun').
`C-M-q'
Reindent each line in the balanced expression that follows point
(`c-indent-exp'). A prefix argument inhibits error checking and
warning messages about invalid syntax.
`<TAB>'
Reindent the current line, and/or in some cases insert a tab
character (`c-indent-command').
If `c-tab-always-indent' is `t', this command always reindents the
current line and does nothing else. This is the default.
If that variable is `nil', this command reindents the current line
only if point is at the left margin or in the line's indentation;
otherwise, it inserts a tab (or the equivalent number of spaces,
if `indent-tabs-mode' is `nil').
Any other value (not `nil' or `t') means always reindent the line,
and also insert a tab if within a comment, a string, or a
preprocessor directive.
`C-u <TAB>'
Reindent the current line according to its syntax; also rigidly
reindent any other lines of the expression that starts on the
current line. *Note Multi-line Indent::.
To reindent the whole current buffer, type `C-x h C-M-\'. This
first selects the whole buffer as the region, then reindents that
region.
To reindent the current block, use `C-M-u C-M-q'. This moves to the
front of the block and then reindents it all.
Customizing C Indentation
-------------------------
C mode and related modes use a simple yet flexible mechanism for
customizing indentation. The mechanism works in two steps: first it
classifies the line syntactically according to its contents and context;
second, it associates each kind of syntactic construct with an
indentation offset which you can customize.
Step 1--Syntactic Analysis
..........................
In the first step, the C indentation mechanism looks at the line
before the one you are currently indenting and determines the syntactic
components of the construct on that line. It builds a list of these
syntactic components, each of which contains a "syntactic symbol" and
sometimes also a buffer position. Some syntactic symbols describe
grammatical elements, for example `statement' and `substatement';
others describe locations amidst grammatical elements, for example
`class-open' and `knr-argdecl'.
Conceptually, a line of C code is always indented relative to the
indentation of some line higher up in the buffer. This is represented
by the buffer positions in the syntactic component list.
Here is an example. Suppose we have the following code in a C++ mode
buffer (the line numbers don't actually appear in the buffer):
1: void swap (int& a, int& b)
2: {
3: int tmp = a;
4: a = b;
5: b = tmp;
6: }
If you type `C-c C-s' (which runs the command
`c-show-syntactic-information') on line 4, it shows the result of the
indentation mechanism for that line:
((statement . 32))
This indicates that the line is a statement and it is indented
relative to buffer position 32, which happens to be the `i' in `int' on
line 3. If you move the cursor to line 3 and type `C-c C-s', it
displays this:
((defun-block-intro . 28))
This indicates that the `int' line is the first statement in a
block, and is indented relative to buffer position 28, which is the
brace just after the function header.
Here is another example:
1: int add (int val, int incr, int doit)
2: {
3: if (doit)
4: {
5: return (val + incr);
6: }
7: return (val);
8: }
Typing `C-c C-s' on line 4 displays this:
((substatement-open . 43))
This says that the brace *opens* a substatement block. By the way,
a "substatement" indicates the line after an `if', `else', `while',
`do', `switch', `for', `try', `catch', `finally', or `synchronized'
statement.
Within the C indentation commands, after a line has been analyzed
syntactically for indentation, the variable `c-syntactic-context'
contains a list that describes the results. Each element in this list
is a "syntactic component": a cons cell containing a syntactic symbol
and (optionally) its corresponding buffer position. There may be
several elements in a component list; typically only one element has a
buffer position.
Step 2--Indentation Calculation
...............................
The C indentation mechanism calculates the indentation for the
current line using the list of syntactic components,
`c-syntactic-context', derived from syntactic analysis. Each component
is a cons cell that contains a syntactic symbol and may also contain a
buffer position.
Each component contributes to the final total indentation of the line
in two ways. First, the syntactic symbol identifies an element of
`c-offsets-alist', which is an association list mapping syntactic
symbols into indentation offsets. Each syntactic symbol's offset adds
to the total indentation. Second, if the component includes a buffer
position, the column number of that position adds to the indentation.
All these offsets and column numbers, added together, give the total
indentation.
The following examples demonstrate the workings of the C indentation
mechanism:
1: void swap (int& a, int& b)
2: {
3: int tmp = a;
4: a = b;
5: b = tmp;
6: }
Suppose that point is on line 3 and you type <TAB> to reindent the
line. As explained above (*note Syntactic Analysis::.), the syntactic
component list for that line is:
((defun-block-intro . 28))
In this case, the indentation calculation first looks up
`defun-block-intro' in the `c-offsets-alist' alist. Suppose that it
finds the integer 2; it adds this to the running total (initialized to
zero), yielding a updated total indentation of 2 spaces.
The next step is to find the column number of buffer position 28.
Since the brace at buffer position 28 is in column zero, this adds 0 to
the running total. Since this line has only one syntactic component,
the total indentation for the line is 2 spaces.
1: int add (int val, int incr, int doit)
2: {
3: if (doit)
4: {
5: return(val + incr);
6: }
7: return(val);
8: }
If you type <TAB> on line 4, the same process is performed, but with
different data. The syntactic component list for this line is:
((substatement-open . 43))
Here, the indentation calculation's first job is to look up the
symbol `substatement-open' in `c-offsets-alist'. Let's assume that the
offset for this symbol is 2. At this point the running total is 2 (0 +
2 = 2). Then it adds the column number of buffer position 43, which is
the `i' in `if' on line 3. This character is in column 2 on that line.
Adding this yields a total indentation of 4 spaces.
If a syntactic symbol in the analysis of a line does not appear in
`c-offsets-alist', it is ignored; if in addition the variable
`c-strict-syntax-p' is non-`nil', it is an error.
Changing Indentation Style
..........................
There are two ways to customize the indentation style for the C-like
modes. First, you can select one of several predefined styles, each of
which specifies offsets for all the syntactic symbols. For more
flexibility, you can customize the handling of individual syntactic
symbols. *Note Syntactic Symbols::, for a list of all defined syntactic
symbols.
`M-x c-set-style <RET> STYLE <RET>'
Select predefined indentation style STYLE. Type `?' when entering
STYLE to see a list of supported styles; to find out what a style
looks like, select it and reindent some C code.
`C-c C-o SYMBOL <RET> OFFSET <RET>'
Set the indentation offset for syntactic symbol SYMBOL
(`c-set-offset'). The second argument OFFSET specifies the new
indentation offset.
The `c-offsets-alist' variable controls the amount of indentation to
give to each syntactic symbol. Its value is an association list, and
each element of the list has the form `(SYNTACTIC-SYMBOL . OFFSET)'.
By changing the offsets for various syntactic symbols, you can
customize indentation in fine detail. To change this alist, use
`c-set-offset' (see below).
Each offset value in `c-offsets-alist' can be an integer, a function
or variable name, a list, or one of the following symbols: `+', `-',
`++', `--', `*', or `/', indicating positive or negative multiples of
the variable `c-basic-offset'. Thus, if you want to change the levels
of indentation to be 3 spaces instead of 2 spaces, set `c-basic-offset'
to 3.
Using a function as the offset value provides the ultimate
flexibility in customizing indentation. The function is called with a
single argument containing the `cons' of the syntactic symbol and the
buffer position, if any. The function should return an integer offset.
If the offset value is a list, its elements are processed according
to the rules above until a non-`nil' value is found. That value is
then added to the total indentation in the normal manner. The primary
use for this is to combine the results of several functions.
The command `C-c C-o' (`c-set-offset') is the easiest way to set
offsets, both interactively or in your `~/.emacs' file. First specify
the syntactic symbol, then the offset you want. *Note Syntactic
Symbols::, for a list of valid syntactic symbols and their meanings.
Syntactic Symbols
.................
Here is a table of valid syntactic symbols for indentation in C and
related modes, with their syntactic meanings. Normally, most of these
symbols are assigned offsets in `c-offsets-alist'.
`string'
Inside a multi-line string.
`c'
Inside a multi-line C style block comment.
`defun-open'
On a brace that opens a function definition.
`defun-close'
On a brace that closes a function definition.
`defun-block-intro'
In the first line in a top-level defun.
`class-open'
On a brace that opens a class definition.
`class-close'
On a brace that closes a class definition.
`inline-open'
On a brace that opens an in-class inline method.
`inline-close'
On a brace that closes an in-class inline method.
`extern-lang-open'
On a brace that opens an external language block.
`extern-lang-close'
On a brace that closes an external language block.
`func-decl-cont'
The region between a function definition's argument list and the
defun opening brace (excluding K&R function definitions). In C,
you cannot put anything but whitespace and comments between them;
in C++ and Java, `throws' declarations and other things can appear
in this context.
`knr-argdecl-intro'
On the first line of a K&R C argument declaration.
`knr-argdecl'
In one of the subsequent lines in a K&R C argument declaration.
`topmost-intro'
On the first line in a topmost construct definition.
`topmost-intro-cont'
On the topmost definition continuation lines.
`member-init-intro'
On the first line in a member initialization list.
`member-init-cont'
On one of the subsequent member initialization list lines.
`inher-intro'
On the first line of a multiple inheritance list.
`inher-cont'
On one of the subsequent multiple inheritance lines.
`block-open'
On a statement block open brace.
`block-close'
On a statement block close brace.
`brace-list-open'
On the opening brace of an `enum' or `static' array list.
`brace-list-close'
On the closing brace of an `enum' or `static' array list.
`brace-list-intro'
On the first line in an `enum' or `static' array list.
`brace-list-entry'
On one of the subsequent lines in an `enum' or `static' array list.
`brace-entry-open'
On one of the subsequent lines in an `enum' or `static' array
list, when the line begins with an open brace.
`statement'
On an ordinary statement.
`statement-cont'
On a continuation line of a statement.
`statement-block-intro'
On the first line in a new statement block.
`statement-case-intro'
On the first line in a `case' "block."
`statement-case-open'
On the first line in a `case' block starting with brace.
`inexpr-statement'
On a statement block inside an expression. This is used for a GNU
extension to the C language, and for Pike special functions that
take a statement block as an argument.
`inexpr-class'
On a class definition inside an expression. This is used for
anonymous classes and anonymous array initializers in Java.
`substatement'
On the first line after an `if', `while', `for', `do', or `else'.
`substatement-open'
On the brace that opens a substatement block.
`case-label'
On a `case' or `default' label.
`access-label'
On a C++ `private', `protected', or `public' access label.
`label'
On any ordinary label.
`do-while-closure'
On the `while' that ends a `do'-`while' construct.
`else-clause'
On the `else' of an `if'-`else' construct.
`catch-clause'
On the `catch' and `finally' lines in `try'...`catch' constructs
in C++ and Java.
`comment-intro'
On a line containing only a comment introduction.
`arglist-intro'
On the first line in an argument list.
`arglist-cont'
On one of the subsequent argument list lines when no arguments
follow on the same line as the arglist opening parenthesis.
`arglist-cont-nonempty'
On one of the subsequent argument list lines when at least one
argument follows on the same line as the arglist opening
parenthesis.
`arglist-close'
On the closing parenthesis of an argument list.
`stream-op'
On one of the lines continuing a stream operator construct.
`inclass'
On a construct that is nested inside a class definition. The
indentation is relative to the open brace of the class definition.
`inextern-lang'
On a construct that is nested inside an external language block.
`inexpr-statement'
On the first line of statement block inside an expression. This
is used for the GCC extension to C that uses the syntax `({ ...
})'. It is also used for the special functions that takes a
statement block as an argument in Pike.
`inexpr-class'
On the first line of a class definition inside an expression.
This is used for anonymous classes and anonymous array
initializers in Java.
`cpp-macro'
On the start of a cpp macro.
`friend'
On a C++ `friend' declaration.
`objc-method-intro'
On the first line of an Objective-C method definition.
`objc-method-args-cont'
On one of the lines continuing an Objective-C method definition.
`objc-method-call-cont'
On one of the lines continuing an Objective-C method call.
`inlambda'
Like `inclass', but used inside lambda (i.e. anonymous) functions.
Only used in Pike.
`lambda-intro-cont'
On a line continuing the header of a lambda function, between the
`lambda' keyword and the function body. Only used in Pike.
Variables for C Indentation
...........................
This section describes additional variables which control the
indentation behavior of C mode and related mode.
`c-offsets-alist'
Association list of syntactic symbols and their indentation
offsets. You should not set this directly, only with
`c-set-offset'. *Note Changing Indent Style::, for details.
`c-style-alist'
Variable for defining indentation styles; see below.
`c-basic-offset'
Amount of basic offset used by `+' and `-' symbols in
`c-offsets-alist'.
`c-special-indent-hook'
Hook for user-defined special indentation adjustments. This hook
is called after a line is indented by C mode and related modes.
The variable `c-style-alist' specifies the predefined indentation
styles. Each element has form `(NAME VARIABLE-SETTING...)', where NAME
is the name of the style. Each VARIABLE-SETTING has the form `(VARIABLE
. VALUE)'; VARIABLE is one of the customization variables used by C
mode, and VALUE is the value for that variable when using the selected
style.
When VARIABLE is `c-offsets-alist', that is a special case: VALUE is
appended to the front of the value of `c-offsets-alist' instead of
replacing that value outright. Therefore, it is not necessary for
VALUE to specify each and every syntactic symbol--only those for which
the style differs from the default.
The indentation of lines containing only comments is also affected by
the variable `c-comment-only-line-offset' (*note Comments in C::.).
C Indentation Styles
....................
A "C style" is a collection of indentation style customizations.
Emacs comes with several predefined indentation styles for C and related
modes, including `gnu', `k&r', `bsd', `stroustrup', `linux', `python',
`java', `whitesmith', `ellemtel', and `cc-mode'. The default style is
`gnu'.
To choose the style you want, use the command `M-x c-set-style'.
Specify a style name as an argument (case is not significant in C style
names). The chosen style only affects newly visited buffers, not those
you are already editing. You can also set the variable
`c-default-style' to specify the style for various major modes. Its
value should be an alist, in which each element specifies one major
mode and which indentation style to use for it. For example,
(setq c-default-style
'((java-mode . "java") (other . "gnu")))
specifies an explicit choice for Java mode, and the default `gnu' style
for the other C-like modes.
To define a new C indentation style, call the function `c-add-style':
(c-add-style NAME VALUES USE-NOW)
Here NAME is the name of the new style (a string), and VALUES is an
alist whose elements have the form `(VARIABLE . VALUE)'. The variables
you specify should be among those documented in *Note Variables for C
Indent::.
If USE-NOW is non-`nil', `c-add-style' switches to the new style
after defining it.
Automatic Display Of Matching Parentheses
=========================================
The Emacs parenthesis-matching feature is designed to show
automatically how parentheses match in the text. Whenever you type a
self-inserting character that is a closing delimiter, the cursor moves
momentarily to the location of the matching opening delimiter, provided
that is on the screen. If it is not on the screen, some text near it is
displayed in the echo area. Either way, you can tell what grouping is
being closed off.
In Lisp, automatic matching applies only to parentheses. In C, it
applies to braces and brackets too. Emacs knows which characters to
regard as matching delimiters based on the syntax table, which is set
by the major mode. *Note Syntax::.
If the opening delimiter and closing delimiter are mismatched--such
as in `[x)'--a warning message is displayed in the echo area. The
correct matches are specified in the syntax table.
Three variables control parenthesis match display.
`blink-matching-paren' turns the feature on or off; `nil' turns it off,
but the default is `t' to turn match display on.
`blink-matching-delay' says how many seconds to wait; the default is 1,
but on some systems it is useful to specify a fraction of a second.
`blink-matching-paren-distance' specifies how many characters back to
search to find the matching opening delimiter. If the match is not
found in that far, scanning stops, and nothing is displayed. This is
to prevent scanning for the matching delimiter from wasting lots of
time when there is no match. The default is 12,000.
When using X Windows, you can request a more powerful alternative
kind of automatic parenthesis matching by enabling Show Paren mode.
This mode turns off the usual kind of matching parenthesis display and
instead uses highlighting to show what matches. Whenever point is after
a close parenthesis, the close parenthesis and its matching open
parenthesis are both highlighted; otherwise, if point is before an open
parenthesis, the matching close parenthesis is highlighted. (There is
no need to highlight the open parenthesis after point because the cursor
appears on top of that character.) Use the command `M-x
show-paren-mode' to enable or disable this mode.
Manipulating Comments
=====================
Because comments are such an important part of programming, Emacs
provides special commands for editing and inserting comments.
Comment Commands
----------------
The comment commands insert, kill and align comments.
`M-;'
Insert or align comment (`indent-for-comment').
`C-x ;'
Set comment column (`set-comment-column').
`C-u - C-x ;'
Kill comment on current line (`kill-comment').
`C-M-j'
Like <RET> followed by inserting and aligning a comment
(`indent-new-comment-line').
`M-x comment-region'
Add or remove comment delimiters on all the lines in the region.
The command that creates a comment is `M-;' (`indent-for-comment').
If there is no comment already on the line, a new comment is created,
aligned at a specific column called the "comment column". The comment
is created by inserting the string Emacs thinks comments should start
with (the value of `comment-start'; see below). Point is left after
that string. If the text of the line extends past the comment column,
then the indentation is done to a suitable boundary (usually, at least
one space is inserted). If the major mode has specified a string to
terminate comments, that is inserted after point, to keep the syntax
valid.
`M-;' can also be used to align an existing comment. If a line
already contains the string that starts comments, then `M-;' just moves
point after it and reindents it to the conventional place. Exception:
comments starting in column 0 are not moved.
Some major modes have special rules for indenting certain kinds of
comments in certain contexts. For example, in Lisp code, comments which
start with two semicolons are indented as if they were lines of code,
instead of at the comment column. Comments which start with three
semicolons are supposed to start at the left margin. Emacs understands
these conventions by indenting a double-semicolon comment using <TAB>,
and by not changing the indentation of a triple-semicolon comment at
all.
;; This function is just an example
;;; Here either two or three semicolons are appropriate.
(defun foo (x)
;;; And now, the first part of the function:
;; The following line adds one.
(1+ x)) ; This line adds one.
In C code, a comment preceded on its line by nothing but whitespace
is indented like a line of code.
Even when an existing comment is properly aligned, `M-;' is still
useful for moving directly to the start of the comment.
`C-u - C-x ;' (`kill-comment') kills the comment on the current line,
if there is one. The indentation before the start of the comment is
killed as well. If there does not appear to be a comment in the line,
nothing is done. To reinsert the comment on another line, move to the
end of that line, do `C-y', and then do `M-;' to realign it. Note that
`C-u - C-x ;' is not a distinct key; it is `C-x ;'
(`set-comment-column') with a negative argument. That command is
programmed so that when it receives a negative argument it calls
`kill-comment'. However, `kill-comment' is a valid command which you
could bind directly to a key if you wanted to.
Multiple Lines of Comments
--------------------------
If you are typing a comment and wish to continue it on another line,
you can use the command `C-M-j' (`indent-new-comment-line'). This
terminates the comment you are typing, creates a new blank line
afterward, and begins a new comment indented under the old one. When
Auto Fill mode is on, going past the fill column while typing a comment
causes the comment to be continued in just this fashion. If point is
not at the end of the line when `C-M-j' is typed, the text on the rest
of the line becomes part of the new comment line.
To turn existing lines into comment lines, use the `M-x
comment-region' command. It adds comment delimiters to the lines that
start in the region, thus commenting them out. With a negative
argument, it does the opposite--it deletes comment delimiters from the
lines in the region.
With a positive argument, `comment-region' duplicates the last
character of the comment start sequence it adds; the argument specifies
how many copies of the character to insert. Thus, in Lisp mode, `C-u 2
M-x comment-region' adds `;;' to each line. Duplicating the comment
delimiter is a way of calling attention to the comment. It can also
affect how the comment is indented. In Lisp, for proper indentation,
you should use an argument of two, if between defuns, and three, if
within a defun.
The variable `comment-padding' specifies how many spaces
`comment-region' should insert on each line between the comment
delimiter and the line's original text. The default is 1.
Options Controlling Comments
----------------------------
The comment column is stored in the variable `comment-column'. You
can set it to a number explicitly. Alternatively, the command `C-x ;'
(`set-comment-column') sets the comment column to the column point is
at. `C-u C-x ;' sets the comment column to match the last comment
before point in the buffer, and then does a `M-;' to align the current
line's comment under the previous one. Note that `C-u - C-x ;' runs
the function `kill-comment' as described above.
The variable `comment-column' is per-buffer: setting the variable in
the normal fashion affects only the current buffer, but there is a
default value which you can change with `setq-default'. *Note
Locals::. Many major modes initialize this variable for the current
buffer.
The comment commands recognize comments based on the regular
expression that is the value of the variable `comment-start-skip'.
Make sure this regexp does not match the null string. It may match more
than the comment starting delimiter in the strictest sense of the word;
for example, in C mode the value of the variable is `"/\\*+ *"', which
matches extra stars and spaces after the `/*' itself. (Note that `\\'
is needed in Lisp syntax to include a `\' in the string, which is
needed to deny the first star its special meaning in regexp syntax.
*Note Regexps::.)
When a comment command makes a new comment, it inserts the value of
`comment-start' to begin it. The value of `comment-end' is inserted
after point, so that it will follow the text that you will insert into
the comment. In C mode, `comment-start' has the value `"/* "' and
`comment-end' has the value `" */"'.
The variable `comment-multi-line' controls how `C-M-j'
(`indent-new-comment-line') behaves when used inside a comment. If
`comment-multi-line' is `nil', as it normally is, then the comment on
the starting line is terminated and a new comment is started on the new
following line. If `comment-multi-line' is not `nil', then the new
following line is set up as part of the same comment that was found on
the starting line. This is done by not inserting a terminator on the
old line, and not inserting a starter on the new line. In languages
where multi-line comments work, the choice of value for this variable
is a matter of taste.
The variable `comment-indent-function' should contain a function
that will be called to compute the indentation for a newly inserted
comment or for aligning an existing comment. It is set differently by
various major modes. The function is called with no arguments, but with
point at the beginning of the comment, or at the end of a line if a new
comment is to be inserted. It should return the column in which the
comment ought to start. For example, in Lisp mode, the indent hook
function bases its decision on how many semicolons begin an existing
comment, and on the code in the preceding lines.
Editing Without Unbalanced Parentheses
======================================
`M-('
Put parentheses around next sexp(s) (`insert-parentheses').
`M-)'
Move past next close parenthesis and reindent
(`move-past-close-and-reindent').
The commands `M-(' (`insert-parentheses') and `M-)'
(`move-past-close-and-reindent') are designed to facilitate a style of
editing which keeps parentheses balanced at all times. `M-(' inserts a
pair of parentheses, either together as in `()', or, if given an
argument, around the next several sexps. It leaves point after the
open parenthesis. The command `M-)' moves past the close parenthesis,
deleting any indentation preceding it, and indenting with `C-j' after
it.
For example, instead of typing `( F O O )', you can type `M-( F O
O', which has the same effect except for leaving the cursor before the
close parenthesis.
`M-(' may insert a space before the open parenthesis, depending on
the syntax class of the preceding character. Set
`parens-require-spaces' to `nil' value if you wish to inhibit this.
Completion for Symbol Names
===========================
Usually completion happens in the minibuffer. But one kind of
completion is available in all buffers: completion for symbol names.
The character `M-<TAB>' runs a command to complete the partial
symbol before point against the set of meaningful symbol names. Any
additional characters determined by the partial name are inserted at
point.
If the partial name in the buffer has more than one possible
completion and they have no additional characters in common, a list of
all possible completions is displayed in another window.
In most programming language major modes, `M-<TAB>' runs the command
`complete-symbol', which provides two kinds of completion. Normally it
does completion based on a tags table (*note Tags::.); with a numeric
argument (regardless of the value), it does completion based on the
names listed in the Info file indexes for your language. Thus, to
complete the name of a symbol defined in your own program, use
`M-<TAB>' with no argument; to complete the name of a standard library
function, use `C-u M-<TAB>'. Of course, Info-based completion works
only if there is an Info file for the standard library functions of
your language, and only if it is installed at your site.
In Emacs-Lisp mode, the name space for completion normally consists
of nontrivial symbols present in Emacs--those that have function
definitions, values or properties. However, if there is an
open-parenthesis immediately before the beginning of the partial symbol,
only symbols with function definitions are considered as completions.
The command which implements this is `lisp-complete-symbol'.
In Text mode and related modes, `M-<TAB>' completes words based on
the spell-checker's dictionary. *Note Spelling::.
Which Function Mode
===================
Which Function mode is a minor mode that displays the current
function name in the mode line, as you move around in a buffer.
To enable (or disable) Which Function mode, use the command `M-x
which-function-mode'. This command is global; it applies to all
buffers, both existing ones and those yet to be created. However, this
only affects certain major modes, those listed in the value of
`which-func-modes'. (If the value is `t', then Which Function mode
applies to all major modes that know how to support it--which are the
major modes that support Imenu.)
Documentation Commands
======================
As you edit Lisp code to be run in Emacs, the commands `C-h f'
(`describe-function') and `C-h v' (`describe-variable') can be used to
print documentation of functions and variables that you want to call.
These commands use the minibuffer to read the name of a function or
variable to document, and display the documentation in a window.
For extra convenience, these commands provide default arguments
based on the code in the neighborhood of point. `C-h f' sets the
default to the function called in the innermost list containing point.
`C-h v' uses the symbol name around or adjacent to point as its default.
For Emacs Lisp code, you can also use Eldoc mode. This minor mode
constantly displays in the echo area the argument list for the function
being called at point. (In other words, it finds the function call that
point is contained in, and displays the argument list of that function.)
Eldoc mode applies in Emacs Lisp and Lisp Interaction modes only. Use
the command `M-x eldoc-mode' to enable or disable this feature.
For C, Lisp, and other languages, you can use `C-h C-i'
(`info-lookup-symbol') to view the Info documentation for a symbol.
You specify the symbol with the minibuffer; by default, it uses the
symbol that appears in the buffer at point. The major mode determines
where to look for documentation for the symbol--which Info files and
which indices. You can also use `M-x info-lookup-file' to look for
documentation for a file name.
You can read the "man page" for an operating system command, library
function, or system call, with the `M-x manual-entry' command. It runs
the `man' program to format the man page, and runs it asynchronously if
your system permits, so that you can keep on editing while the page is
being formatted. (MS-DOS and MS-Windows 3 do not permit asynchronous
subprocesses, so on these systems you cannot edit while Emacs waits for
`man' to exit.) The result goes in a buffer named `*Man TOPIC*'.
These buffers use a special major mode, Man mode, that facilitates
scrolling and examining other manual pages. For details, type `C-h m'
while in a man page buffer.
For a long man page, setting the faces properly can take substantial
time. By default, Emacs uses faces in man pages if Emacs can display
different fonts or colors. You can turn off use of faces in man pages
by setting the variable `Man-fontify-manpage-flag' to `nil'.
If you insert the text of a man page into an Emacs buffer in some
other fashion, you can use the command `M-x Man-fontify-manpage' to
perform the same conversions that `M-x manual-entry' does.
Eventually the GNU project hopes to replace most man pages with
better-organized manuals that you can browse with Info. *Note Misc
Help::. Since this process is only partially completed, it is still
useful to read manual pages.
Change Logs
===========
The Emacs command `C-x 4 a' adds a new entry to the change log file
for the file you are editing (`add-change-log-entry-other-window').
A change log file contains a chronological record of when and why you
have changed a program, consisting of a sequence of entries describing
individual changes. Normally it is kept in a file called `ChangeLog'
in the same directory as the file you are editing, or one of its parent
directories. A single `ChangeLog' file can record changes for all the
files in its directory and all its subdirectories.
A change log entry starts with a header line that contains your name,
your email address (taken from the variable `user-mail-address'), and
the current date and time. Aside from these header lines, every line
in the change log starts with a space or a tab. The bulk of the entry
consists of "items", each of which starts with a line starting with
whitespace and a star. Here are two entries, both dated in May 1993,
each with two items:
1993-05-25 Richard Stallman <rms@gnu.org>
* man.el: Rename symbols `man-*' to `Man-*'.
(manual-entry): Make prompt string clearer.
* simple.el (blink-matching-paren-distance):
Change default to 12,000.
1993-05-24 Richard Stallman <rms@gnu.org>
* vc.el (minor-mode-map-alist): Don't use it if it's void.
(vc-cancel-version): Doc fix.
(Previous Emacs versions used a different format for the date.)
One entry can describe several changes; each change should have its
own item. Normally there should be a blank line between items. When
items are related (parts of the same change, in different places), group
them by leaving no blank line between them. The second entry above
contains two items grouped in this way.
`C-x 4 a' visits the change log file and creates a new entry unless
the most recent entry is for today's date and your name. It also
creates a new item for the current file. For many languages, it can
even guess the name of the function or other object that was changed.
The change log file is visited in Change Log mode. In this major
mode, each bunch of grouped items counts as one paragraph, and each
entry is considered a page. This facilitates editing the entries.
`C-j' and auto-fill indent each new line like the previous line; this
is convenient for entering the contents of an entry.
Version control systems are another way to keep track of changes in
your program and keep a change log. *Note Log Buffer::.
Tags Tables
===========
A "tags table" is a description of how a multi-file program is
broken up into files. It lists the names of the component files and the
names and positions of the functions (or other named subunits) in each
file. Grouping the related files makes it possible to search or replace
through all the files with one command. Recording the function names
and positions makes possible the `M-.' command which finds the
definition of a function by looking up which of the files it is in.
Tags tables are stored in files called "tags table files". The
conventional name for a tags table file is `TAGS'.
Each entry in the tags table records the name of one tag, the name
of the file that the tag is defined in (implicitly), and the position
in that file of the tag's definition.
Just what names from the described files are recorded in the tags
table depends on the programming language of the described file. They
normally include all functions and subroutines, and may also include
global variables, data types, and anything else convenient. Each name
recorded is called a "tag".
Source File Tag Syntax
----------------------
Here is how tag syntax is defined for the most popular languages:
* In C code, any C function or typedef is a tag, and so are
definitions of `struct', `union' and `enum'. `#define' macro
definitions and `enum' constants are also tags, unless you specify
`--no-defines' when making the tags table. Similarly, global
variables are tags, unless you specify `--no-globals'. Use of
`--no-globals' and `--no-defines' can make the tags table file
much smaller.
* In C++ code, in addition to all the tag constructs of C code,
member functions are also recognized, and optionally member
variables if you use the `--members' option. Tags for variables
and functions in classes are named `CLASS::VARIABLE' and
`CLASS::FUNCTION'.
* In Java code, tags include all the constructs recognized in C++,
plus the `extends' and `implements' constructs. Tags for variables
and functions in classes are named `CLASS.VARIABLE' and
`CLASS.FUNCTION'.
* In LaTeX text, the argument of any of the commands `\chapter',
`\section', `\subsection', `\subsubsection', `\eqno', `\label',
`\ref', `\cite', `\bibitem', `\part', `\appendix', `\entry', or
`\index', is a tag.
Other commands can make tags as well, if you specify them in the
environment variable `TEXTAGS' before invoking `etags'. The value
of this environment variable should be a colon-separated list of
command names. For example,
TEXTAGS="def:newcommand:newenvironment"
export TEXTAGS
specifies (using Bourne shell syntax) that the commands `\def',
`\newcommand' and `\newenvironment' also define tags.
* In Lisp code, any function defined with `defun', any variable
defined with `defvar' or `defconst', and in general the first
argument of any expression that starts with `(def' in column zero,
is a tag.
* In Scheme code, tags include anything defined with `def' or with a
construct whose name starts with `def'. They also include
variables set with `set!' at top level in the file.
Several other languages are also supported:
* In assembler code, labels appearing at the beginning of a line,
followed by a colon, are tags.
* In Bison or Yacc input files, each rule defines as a tag the
nonterminal it constructs. The portions of the file that contain
C code are parsed as C code.
* In Cobol code, tags are paragraph names; that is, any word
starting in column 8 and followed by a period.
* In Erlang code, the tags are the functions, records, and macros
defined in the file.
* In Fortran code, functions, subroutines and blockdata are tags.
* In Objective C code, tags include Objective C definitions for
classes, class categories, methods, and protocols.
* In Pascal code, the tags are the functions and procedures defined
in the file.
* In Perl code, the tags are the procedures defined by the `sub'
keyword.
* In Postscript code, the tags are the functions.
* In Prolog code, a tag name appears at the left margin.
You can also generate tags based on regexp matching (*note Create
Tags Table::.) to handle other formats and languages.
Creating Tags Tables
--------------------
The `etags' program is used to create a tags table file. It knows
the syntax of several languages, as described in *Note Tag Syntax::.
Here is how to run `etags':
etags INPUTFILES...
The `etags' program reads the specified files, and writes a tags table
named `TAGS' in the current working directory. `etags' recognizes the
language used in an input file based on its file name and contents.
You can specify the language with the `--language=NAME' option,
described below.
If the tags table data become outdated due to changes in the files
described in the table, the way to update the tags table is the same
way it was made in the first place. It is not necessary to do this
often.
If the tags table fails to record a tag, or records it for the wrong
file, then Emacs cannot possibly find its definition. However, if the
position recorded in the tags table becomes a little bit wrong (due to
some editing in the file that the tag definition is in), the only
consequence is a slight delay in finding the tag. Even if the stored
position is very wrong, Emacs will still find the tag, but it must
search the entire file for it.
So you should update a tags table when you define new tags that you
want to have listed, or when you move tag definitions from one file to
another, or when changes become substantial. Normally there is no need
to update the tags table after each edit, or even every day.
One tags table can effectively include another. Specify the included
tags file name with the `--include=FILE' option when creating the file
that is to include it. The latter file then acts as if it contained
all the files specified in the included file, as well as the files it
directly contains.
If you specify the source files with relative file names when you run
`etags', the tags file will contain file names relative to the
directory where the tags file was initially written. This way, you can
move an entire directory tree containing both the tags file and the
source files, and the tags file will still refer correctly to the source
files.
If you specify absolute file names as arguments to `etags', then the
tags file will contain absolute file names. This way, the tags file
will still refer to the same files even if you move it, as long as the
source files remain in the same place. Absolute file names start with
`/', or with `DEVICE:/' on MS-DOS and MS-Windows.
When you want to make a tags table from a great number of files, you
may have problems listing them on the command line, because some systems
have a limit on its length. The simplest way to circumvent this limit
is to tell `etags' to read the file names from its standard input, by
typing a dash in place of the file names, like this:
find . -name "*.[chCH]" -print | etags -
Use the option `--language=NAME' to specify the language explicitly.
You can intermix these options with file names; each one applies to
the file names that follow it. Specify `--language=auto' to tell
`etags' to resume guessing the language from the file names and file
contents. Specify `--language=none' to turn off language-specific
processing entirely; then `etags' recognizes tags by regexp matching
alone. `etags --help' prints the list of the languages `etags' knows,
and the file name rules for guessing the language.
The `--regex' option provides a general way of recognizing tags
based on regexp matching. You can freely intermix it with file names.
Each `--regex' option adds to the preceding ones, and applies only to
the following files. The syntax is:
--regex=/TAGREGEXP[/NAMEREGEXP]/
where TAGREGEXP is used to match the lines to tag. It is always
anchored, that is, it behaves as if preceded by `^'. If you want to
account for indentation, just match any initial number of blanks by
beginning your regular expression with `[ \t]*'. In the regular
expressions, `\' quotes the next character, and `\t' stands for the tab
character. Note that `etags' does not handle the other C escape
sequences for special characters.
The syntax of regular expressions in `etags' is the same as in
Emacs, augmented with the "interval operator", which works as in `grep'
and `ed'. The syntax of an interval operator is `\{M,N\}', and its
meaning is to match the preceding expression at least M times and up to
N times.
You should not match more characters with TAGREGEXP than that needed
to recognize what you want to tag. If the match is such that more
characters than needed are unavoidably matched by TAGREGEXP, you may
find useful to add a NAMEREGEXP, in order to narrow the tag scope. You
can find some examples below.
The `-R' option deletes all the regexps defined with `--regex'
options. It applies to the file names following it, as you can see
from the following example:
etags --regex=/REG1/ voo.doo --regex=/REG2/ \
bar.ber -R --lang=lisp los.er
Here `etags' chooses the parsing language for `voo.doo' and `bar.ber'
according to their contents. `etags' also uses REG1 to recognize
additional tags in `voo.doo', and both REG1 and REG2 to recognize
additional tags in `bar.ber'. `etags' uses the Lisp tags rules, and no
regexp matching, to recognize tags in `los.er'.
Here are some more examples. The regexps are quoted to protect them
from shell interpretation.
* Tag the `DEFVAR' macros in the emacs source files:
--regex='/[ \t]*DEFVAR_[A-Z_ \t(]+"\([^"]+\)"/'
* Tag VHDL files (this example is a single long line, broken here for
formatting reasons):
--language=none
--regex='/[ \t]*\(ARCHITECTURE\|CONFIGURATION\) +[^ ]* +OF/'
--regex='/[ \t]*\(ATTRIBUTE\|ENTITY\|FUNCTION\|PACKAGE\
\( BODY\)?\|PROCEDURE\|PROCESS\|TYPE\)[ \t]+\([^ \t(]+\)/\3/'
* Tag Tcl files (this last example shows the usage of a NAMEREGEXP):
--lang=none --regex='/proc[ \t]+\([^ \t]+\)/\1/'
For a list of the other available `etags' options, execute `etags
--help'.
Selecting a Tags Table
----------------------
Emacs has at any time one "selected" tags table, and all the commands
for working with tags tables use the selected one. To select a tags
table, type `M-x visit-tags-table', which reads the tags table file
name as an argument. The name `TAGS' in the default directory is used
as the default file name.
All this command does is store the file name in the variable
`tags-file-name'. Emacs does not actually read in the tags table
contents until you try to use them. Setting this variable yourself is
just as good as using `visit-tags-table'. The variable's initial value
is `nil'; that value tells all the commands for working with tags tables
that they must ask for a tags table file name to use.
Using `visit-tags-table' when a tags table is already loaded gives
you a choice: you can add the new tags table to the current list of
tags tables, or start a new list. The tags commands use all the tags
tables in the current list. If you start a new list, the new tags table
is used *instead* of others. If you add the new table to the current
list, it is used *as well as* the others. When the tags commands scan
the list of tags tables, they don't always start at the beginning of
the list; they start with the first tags table (if any) that describes
the current file, proceed from there to the end of the list, and then
scan from the beginning of the list until they have covered all the
tables in the list.
You can specify a precise list of tags tables by setting the variable
`tags-table-list' to a list of strings, like this:
(setq tags-table-list
'("~/emacs" "/usr/local/lib/emacs/src"))
This tells the tags commands to look at the `TAGS' files in your
`~/emacs' directory and in the `/usr/local/lib/emacs/src' directory.
The order depends on which file you are in and which tags table
mentions that file, as explained above.
Do not set both `tags-file-name' and `tags-table-list'.
Finding a Tag
-------------
The most important thing that a tags table enables you to do is to
find the definition of a specific tag.
`M-. TAG <RET>'
Find first definition of TAG (`find-tag').
`C-u M-.'
Find next alternate definition of last tag specified.
`C-u - M-.'
Go back to previous tag found.
`C-M-. PATTERN <RET>'
Find a tag whose name matches PATTERN (`find-tag-regexp').
`C-u C-M-.'
Find the next tag whose name matches the last pattern used.
`C-x 4 . TAG <RET>'
Find first definition of TAG, but display it in another window
(`find-tag-other-window').
`C-x 5 . TAG <RET>'
Find first definition of TAG, and create a new frame to select the
buffer (`find-tag-other-frame').
`M-*'
Pop back to where you previously invoked `M-.' and friends.
`M-.' (`find-tag') is the command to find the definition of a
specified tag. It searches through the tags table for that tag, as a
string, and then uses the tags table info to determine the file that the
definition is in and the approximate character position in the file of
the definition. Then `find-tag' visits that file, moves point to the
approximate character position, and searches ever-increasing distances
away to find the tag definition.
If an empty argument is given (just type <RET>), the sexp in the
buffer before or around point is used as the TAG argument. *Note
Lists::, for info on sexps.
You don't need to give `M-.' the full name of the tag; a part will
do. This is because `M-.' finds tags in the table which contain TAG as
a substring. However, it prefers an exact match to a substring match.
To find other tags that match the same substring, give `find-tag' a
numeric argument, as in `C-u M-.'; this does not read a tag name, but
continues searching the tags table's text for another tag containing
the same substring last used. If you have a real <META> key, `M-0 M-.'
is an easier alternative to `C-u M-.'.
Like most commands that can switch buffers, `find-tag' has a variant
that displays the new buffer in another window, and one that makes a
new frame for it. The former is `C-x 4 .', which invokes the command
`find-tag-other-window'. The latter is `C-x 5 .', which invokes
`find-tag-other-frame'.
To move back to places you've found tags recently, use `C-u - M-.';
more generally, `M-.' with a negative numeric argument. This command
can take you to another buffer. `C-x 4 .' with a negative argument
finds the previous tag location in another window.
As well as going back to places you've found tags recently, you can
go back to places *from where* you found them. Use `M-*', which
invokes the command `pop-tag-mark', for this. Typically you would find
and study the definition of something with `M-.' and then return to
where you were with `M-*'.
Both `C-u - M-.' and `M-*' allow you to retrace your steps to a
depth determined by the variable `find-tag-marker-ring-length'.
The command `C-M-.' (`find-tag-regexp') visits the tags that match a
specified regular expression. It is just like `M-.' except that it
does regexp matching instead of substring matching.
Searching and Replacing with Tags Tables
----------------------------------------
The commands in this section visit and search all the files listed
in the selected tags table, one by one. For these commands, the tags
table serves only to specify a sequence of files to search.
`M-x tags-search <RET> REGEXP <RET>'
Search for REGEXP through the files in the selected tags table.
`M-x tags-query-replace <RET> REGEXP <RET> REPLACEMENT <RET>'
Perform a `query-replace-regexp' on each file in the selected tags
table.
`M-,'
Restart one of the commands above, from the current location of
point (`tags-loop-continue').
`M-x tags-search' reads a regexp using the minibuffer, then searches
for matches in all the files in the selected tags table, one file at a
time. It displays the name of the file being searched so you can
follow its progress. As soon as it finds an occurrence, `tags-search'
returns.
Having found one match, you probably want to find all the rest. To
find one more match, type `M-,' (`tags-loop-continue') to resume the
`tags-search'. This searches the rest of the current buffer, followed
by the remaining files of the tags table.
`M-x tags-query-replace' performs a single `query-replace-regexp'
through all the files in the tags table. It reads a regexp to search
for and a string to replace with, just like ordinary `M-x
query-replace-regexp'. It searches much like `M-x tags-search', but
repeatedly, processing matches according to your input. *Note
Replace::, for more information on query replace.
It is possible to get through all the files in the tags table with a
single invocation of `M-x tags-query-replace'. But often it is useful
to exit temporarily, which you can do with any input event that has no
special query replace meaning. You can resume the query replace
subsequently by typing `M-,'; this command resumes the last tags search
or replace command that you did.
The commands in this section carry out much broader searches than the
`find-tag' family. The `find-tag' commands search only for definitions
of tags that match your substring or regexp. The commands
`tags-search' and `tags-query-replace' find every occurrence of the
regexp, as ordinary search commands and replace commands do in the
current buffer.
These commands create buffers only temporarily for the files that
they have to search (those which are not already visited in Emacs
buffers). Buffers in which no match is found are quickly killed; the
others continue to exist.
It may have struck you that `tags-search' is a lot like `grep'. You
can also run `grep' itself as an inferior of Emacs and have Emacs show
you the matching lines one by one. This works much like running a
compilation; finding the source locations of the `grep' matches works
like finding the compilation errors. *Note Compilation::.
Tags Table Inquiries
--------------------
`M-x list-tags <RET> FILE <RET>'
Display a list of the tags defined in the program file FILE.
`M-x tags-apropos <RET> REGEXP <RET>'
Display a list of all tags matching REGEXP.
`M-x list-tags' reads the name of one of the files described by the
selected tags table, and displays a list of all the tags defined in
that file. The "file name" argument is really just a string to compare
against the file names recorded in the tags table; it is read as a
string rather than as a file name. Therefore, completion and
defaulting are not available, and you must enter the file name the same
way it appears in the tags table. Do not include a directory as part of
the file name unless the file name recorded in the tags table includes a
directory.
`M-x tags-apropos' is like `apropos' for tags (*note Apropos::.).
It reads a regexp, then finds all the tags in the selected tags table
whose entries match that regexp, and displays the tag names found.
You can also perform completion in the buffer on the name space of
tag names in the current tags tables. *Note Symbol Completion::.
Merging Files with Emerge
=========================
It's not unusual for programmers to get their signals crossed and
modify the same program in two different directions. To recover from
this confusion, you need to merge the two versions. Emerge makes this
easier. See also *Note Comparing Files::, for commands to compare in a
more manual fashion, and *Note Emerge: (ediff)Emerge.
Overview of Emerge
------------------
To start Emerge, run one of these four commands:
`M-x emerge-files'
Merge two specified files.
`M-x emerge-files-with-ancestor'
Merge two specified files, with reference to a common ancestor.
`M-x emerge-buffers'
Merge two buffers.
`M-x emerge-buffers-with-ancestor'
Merge two buffers with reference to a common ancestor in a third
buffer.
The Emerge commands compare two files or buffers, and display the
comparison in three buffers: one for each input text (the "A buffer"
and the "B buffer"), and one (the "merge buffer") where merging takes
place. The merge buffer shows the full merged text, not just the
differences. Wherever the two input texts differ, you can choose which
one of them to include in the merge buffer.
The Emerge commands that take input from existing buffers use only
the accessible portions of those buffers, if they are narrowed (*note
Narrowing::.).
If a common ancestor version is available, from which the two texts
to be merged were both derived, Emerge can use it to guess which
alternative is right. Wherever one current version agrees with the
ancestor, Emerge presumes that the other current version is a deliberate
change which should be kept in the merged version. Use the
`with-ancestor' commands if you want to specify a common ancestor text.
These commands read three file or buffer names--variant A, variant B,
and the common ancestor.
After the comparison is done and the buffers are prepared, the
interactive merging starts. You control the merging by typing special
"merge commands" in the merge buffer. The merge buffer shows you a
full merged text, not just differences. For each run of differences
between the input texts, you can choose which one of them to keep, or
edit them both together.
The merge buffer uses a special major mode, Emerge mode, with
commands for making these choices. But you can also edit the buffer
with ordinary Emacs commands.
At any given time, the attention of Emerge is focused on one
particular difference, called the "selected" difference. This
difference is marked off in the three buffers like this:
vvvvvvvvvvvvvvvvvvvv
TEXT THAT DIFFERS
^^^^^^^^^^^^^^^^^^^^
Emerge numbers all the differences sequentially and the mode line
always shows the number of the selected difference.
Normally, the merge buffer starts out with the A version of the text.
But when the A version of a difference agrees with the common ancestor,
then the B version is initially preferred for that difference.
Emerge leaves the merged text in the merge buffer when you exit. At
that point, you can save it in a file with `C-x C-w'. If you give a
numeric argument to `emerge-files' or `emerge-files-with-ancestor', it
reads the name of the output file using the minibuffer. (This is the
last file name those commands read.) Then exiting from Emerge saves
the merged text in the output file.
Normally, Emerge commands save the output buffer in its file when you
exit. If you abort Emerge with `C-]', the Emerge command does not save
the output buffer, but you can save it yourself if you wish.
Submodes of Emerge
------------------
You can choose between two modes for giving merge commands: Fast mode
and Edit mode. In Fast mode, basic merge commands are single
characters, but ordinary Emacs commands are disabled. This is
convenient if you use only merge commands. In Edit mode, all merge
commands start with the prefix key `C-c C-c', and the normal Emacs
commands are also available. This allows editing the merge buffer, but
slows down Emerge operations.
Use `e' to switch to Edit mode, and `C-c C-c f' to switch to Fast
mode. The mode line indicates Edit and Fast modes with `E' and `F'.
Emerge has two additional submodes that affect how particular merge
commands work: Auto Advance mode and Skip Prefers mode.
If Auto Advance mode is in effect, the `a' and `b' commands advance
to the next difference. This lets you go through the merge faster as
long as you simply choose one of the alternatives from the input. The
mode line indicates Auto Advance mode with `A'.
If Skip Prefers mode is in effect, the `n' and `p' commands skip
over differences in states prefer-A and prefer-B (*note State of
Difference::.). Thus you see only differences for which neither version
is presumed "correct." The mode line indicates Skip Prefers mode with
`S'.
Use the command `s a' (`emerge-auto-advance-mode') to set or clear
Auto Advance mode. Use `s s' (`emerge-skip-prefers-mode') to set or
clear Skip Prefers mode. These commands turn on the mode with a
positive argument, turns it off with a negative or zero argument, and
toggle the mode with no argument.
State of a Difference
---------------------
In the merge buffer, a difference is marked with lines of `v' and
`^' characters. Each difference has one of these seven states:
A
The difference is showing the A version. The `a' command always
produces this state; the mode line indicates it with `A'.
B
The difference is showing the B version. The `b' command always
produces this state; the mode line indicates it with `B'.
default-A
default-B
The difference is showing the A or the B state by default, because
you haven't made a choice. All differences start in the default-A
state (and thus the merge buffer is a copy of the A buffer),
except those for which one alternative is "preferred" (see below).
When you select a difference, its state changes from default-A or
default-B to plain A or B. Thus, the selected difference never has
state default-A or default-B, and these states are never displayed
in the mode line.
The command `d a' chooses default-A as the default state, and `d
b' chooses default-B. This chosen default applies to all
differences which you haven't ever selected and for which no
alternative is preferred. If you are moving through the merge
sequentially, the differences you haven't selected are those
following the selected one. Thus, while moving sequentially, you
can effectively make the A version the default for some sections
of the merge buffer and the B version the default for others by
using `d a' and `d b' between sections.
prefer-A
prefer-B
The difference is showing the A or B state because it is
"preferred". This means that you haven't made an explicit choice,
but one alternative seems likely to be right because the other
alternative agrees with the common ancestor. Thus, where the A
buffer agrees with the common ancestor, the B version is
preferred, because chances are it is the one that was actually
changed.
These two states are displayed in the mode line as `A*' and `B*'.
combined
The difference is showing a combination of the A and B states, as a
result of the `x c' or `x C' commands.
Once a difference is in this state, the `a' and `b' commands don't
do anything to it unless you give them a numeric argument.
The mode line displays this state as `comb'.
Merge Commands
--------------
Here are the Merge commands for Fast mode; in Edit mode, precede them
with `C-c C-c':
`p'
Select the previous difference.
`n'
Select the next difference.
`a'
Choose the A version of this difference.
`b'
Choose the B version of this difference.
`C-u N j'
Select difference number N.
`.'
Select the difference containing point. You can use this command
in the merge buffer or in the A or B buffer.
`q'
Quit--finish the merge.
`C-]'
Abort--exit merging and do not save the output.
`f'
Go into Fast mode. (In Edit mode, this is actually `C-c C-c f'.)
`e'
Go into Edit mode.
`l'
Recenter (like `C-l') all three windows.
`-'
Specify part of a prefix numeric argument.
`DIGIT'
Also specify part of a prefix numeric argument.
`d a'
Choose the A version as the default from here down in the merge
buffer.
`d b'
Choose the B version as the default from here down in the merge
buffer.
`c a'
Copy the A version of this difference into the kill ring.
`c b'
Copy the B version of this difference into the kill ring.
`i a'
Insert the A version of this difference at point.
`i b'
Insert the B version of this difference at point.
`m'
Put point and mark around the difference.
`^'
Scroll all three windows down (like `M-v').
`v'
Scroll all three windows up (like `C-v').
`<'
Scroll all three windows left (like `C-x <').
`>'
Scroll all three windows right (like `C-x >').
`|'
Reset horizontal scroll on all three windows.
`x 1'
Shrink the merge window to one line. (Use `C-u l' to restore it
to full size.)
`x c'
Combine the two versions of this difference (*note Combining in
Emerge::.).
`x f'
Show the names of the files/buffers Emerge is operating on, in a
Help window. (Use `C-u l' to restore windows.)
`x j'
Join this difference with the following one. (`C-u x j' joins
this difference with the previous one.)
`x s'
Split this difference into two differences. Before you use this
command, position point in each of the three buffers at the place
where you want to split the difference.
`x t'
Trim identical lines off the top and bottom of the difference.
Such lines occur when the A and B versions are identical but
differ from the ancestor version.
Exiting Emerge
--------------
The `q' command (`emerge-quit') finishes the merge, storing the
results into the output file if you specified one. It restores the A
and B buffers to their proper contents, or kills them if they were
created by Emerge and you haven't changed them. It also disables the
Emerge commands in the merge buffer, since executing them later could
damage the contents of the various buffers.
`C-]' aborts the merge. This means exiting without writing the
output file. If you didn't specify an output file, then there is no
real difference between aborting and finishing the merge.
If the Emerge command was called from another Lisp program, then its
return value is `t' for successful completion, or `nil' if you abort.
Combining the Two Versions
--------------------------
Sometimes you want to keep *both* alternatives for a particular
difference. To do this, use `x c', which edits the merge buffer like
this:
#ifdef NEW
VERSION FROM A BUFFER
#else /* not NEW */
VERSION FROM B BUFFER
#endif /* not NEW */
While this example shows C preprocessor conditionals delimiting the two
alternative versions, you can specify the strings to use by setting the
variable `emerge-combine-versions-template' to a string of your choice.
In the string, `%a' says where to put version A, and `%b' says where
to put version B. The default setting, which produces the results
shown above, looks like this:
"#ifdef NEW\n%a#else /* not NEW */\n%b#endif /* not NEW */\n"
Fine Points of Emerge
---------------------
During the merge, you mustn't try to edit the A and B buffers
yourself. Emerge modifies them temporarily, but ultimately puts them
back the way they were.
You can have any number of merges going at once--just don't use any
one buffer as input to more than one merge at once, since the temporary
changes made in these buffers would get in each other's way.
Starting Emerge can take a long time because it needs to compare the
files fully. Emacs can't do anything else until `diff' finishes.
Perhaps in the future someone will change Emerge to do the comparison in
the background when the input files are large--then you could keep on
doing other things with Emacs until Emerge is ready to accept commands.
After setting up the merge, Emerge runs the hook
`emerge-startup-hook' (*note Hooks::.).
C and Related Modes
===================
This section describes special features available in C, C++,
Objective-C, Java, CORBA IDL, and Pike modes. When we say "C mode and
related modes," those are the modes we mean.
C Mode Motion Commands
----------------------
This section describes commands for moving point, in C mode and
related modes.
`C-c C-u'
Move point back to the containing preprocessor conditional,
leaving the mark behind. A prefix argument acts as a repeat
count. With a negative argument, move point forward to the end of
the containing preprocessor conditional. When going backwards,
`#elif' is treated like `#else' followed by `#if'. When going
forwards, `#elif' is ignored.
`C-c C-p'
Move point back over a preprocessor conditional, leaving the mark
behind. A prefix argument acts as a repeat count. With a negative
argument, move forward.
`C-c C-n'
Move point forward across a preprocessor conditional, leaving the
mark behind. A prefix argument acts as a repeat count. With a
negative argument, move backward.
`M-a'
Move point to the beginning of the innermost C statement
(`c-beginning-of-statement'). If point is already at the beginning
of a statement, move to the beginning of the preceding statement.
With prefix argument N, move back N - 1 statements.
If point is within a string or comment, or next to a comment (only
whitespace between them), this command moves by sentences instead
of statements.
When called from a program, this function takes three optional
arguments: the numeric prefix argument, a buffer position limit
(don't move back before that place), and a flag that controls
whether to do sentence motion when inside of a comment.
`M-e'
Move point to the end of the innermost C statement; like `M-a'
except that it moves in the other direction (`c-end-of-statement').
`M-x c-backward-into-nomenclature'
Move point backward to beginning of a C++ nomenclature section or
word. With prefix argument N, move N times. If N is negative,
move forward. C++ nomenclature means a symbol name in the style
of NamingSymbolsWithMixedCaseAndNoUnderlines; each capital letter
begins a section or word.
In the GNU project, we recommend using underscores to separate
words within an identifier in C or C++, rather than using case
distinctions.
`M-x c-forward-into-nomenclature'
Move point forward to end of a C++ nomenclature section or word.
With prefix argument N, move N times.
Electric C Characters
---------------------
In C mode and related modes, certain printing characters are
"electric"--in addition to inserting themselves, they also reindent the
current line and may insert newlines. This feature is controlled by
the variable `c-auto-newline'. The "electric" characters are `{', `}',
`:', `#', `;', `,', `<', `>', `/', `*', `(', and `)'.
Electric characters insert newlines only when the "auto-newline"
feature is enabled (indicated by `/a' in the mode line after the mode
name). This feature is controlled by the variable `c-auto-newline'.
You can turn this feature on or off with the command `C-c C-a':
`C-c C-a'
Toggle the auto-newline feature (`c-toggle-auto-state'). With a
prefix argument, this command turns the auto-newline feature on if
the argument is positive, and off if it is negative.
The colon character is electric because that is appropriate for a
single colon. But when you want to insert a double colon in C++, the
electric behavior of colon is inconvenient. You can insert a double
colon with no reindentation or newlines by typing `C-c :':
`C-c :'
Insert a double colon scope operator at point, without reindenting
the line or adding any newlines (`c-scope-operator').
The electric `#' key reindents the line if it appears to be the
beginning of a preprocessor directive. This happens when the value of
`c-electric-pound-behavior' is `(alignleft)'. You can turn this
feature off by setting `c-electric-pound-behavior' to `nil'.
The variable `c-hanging-braces-alist' controls the insertion of
newlines before and after inserted braces. It is an association list
with elements of the following form: `(SYNTACTIC-SYMBOL . NL-LIST)'.
Most of the syntactic symbols that appear in `c-offsets-alist' are
meaningful here as well.
The list NL-LIST may contain either of the symbols `before' or
`after', or both; or it may be `nil'. When a brace is inserted, the
syntactic context it defines is looked up in `c-hanging-braces-alist';
if it is found, the NL-LIST is used to determine where newlines are
inserted: either before the brace, after, or both. If not found, the
default is to insert a newline both before and after braces.
The variable `c-hanging-colons-alist' controls the insertion of
newlines before and after inserted colons. It is an association list
with elements of the following form: `(SYNTACTIC-SYMBOL . NL-LIST)'.
The list NL-LIST may contain either of the symbols `before' or `after',
or both; or it may be `nil'.
When a colon is inserted, the syntactic symbol it defines is looked
up in this list, and if found, the NL-LIST is used to determine where
newlines are inserted: either before the brace, after, or both. If the
syntactic symbol is not found in this list, no newlines are inserted.
Electric characters can also delete newlines automatically when the
auto-newline feature is enabled. This feature makes auto-newline more
acceptable, by deleting the newlines in the most common cases where you
do not want them. Emacs can recognize several cases in which deleting a
newline might be desirable; by setting the variable `c-cleanup-list',
you can specify *which* of these cases that should happen. The
variable's value is a list of symbols, each describing one case for
possible deletion of a newline. Here are the meaningful symbols, and
their meanings:
`brace-catch-brace'
Clean up `} catch (CONDITION) {' constructs by placing the entire
construct on a single line. The clean-up occurs when you type the
`{', if there is nothing between the braces aside from `catch' and
CONDITION.
`brace-else-brace'
Clean up `} else {' constructs by placing the entire construct on
a single line. The clean-up occurs when you type the `{' after
the `else', but only if there is nothing but white space between
the braces and the `else'.
`brace-elseif-brace'
Clean up `} else if (...) {' constructs by placing the entire
construct on a single line. The clean-up occurs when you type the
`{', if there is nothing but white space between the `}' and `{'
aside from the keywords and the `if'-condition.
`empty-defun-braces'
Clean up empty defun braces by placing the braces on the same
line. Clean-up occurs when you type the closing brace.
`defun-close-semi'
Clean up the semicolon after a `struct' or similar type
declaration, by placing the semicolon on the same line as the
closing brace. Clean-up occurs when you type the semicolon.
`list-close-comma'
Clean up commas following braces in array and aggregate
initializers. Clean-up occurs when you type the comma.
`scope-operator'
Clean up double colons which may designate a C++ scope operator, by
placing the colons together. Clean-up occurs when you type the
second colon, but only when the two colons are separated by
nothing but whitespace.
Hungry Delete Feature in C
--------------------------
When the "hungry-delete" feature is enabled (indicated by `/h' or
`/ah' in the mode line after the mode name), a single <DEL> command
deletes all preceding whitespace, not just one space. To turn this
feature on or off, use `C-c C-d':
`C-c C-d'
Toggle the hungry-delete feature (`c-toggle-hungry-state'). With a
prefix argument, this command turns the hungry-delete feature on
if the argument is positive, and off if it is negative.
`C-c C-t'
Toggle the auto-newline and hungry-delete features, both at once
(`c-toggle-auto-hungry-state').
The variable `c-hungry-delete-key' controls whether the
hungry-delete feature is enabled.
Other Commands for C Mode
-------------------------
`C-M-h'
Put mark at the end of a function definition, and put point at the
beginning (`c-mark-function').
`M-q'
Fill a paragraph, handling C and C++ comments (`c-fill-paragraph').
If any part of the current line is a comment or within a comment,
this command fills the comment or the paragraph of it that point
is in, preserving the comment indentation and comment delimiters.
`C-c C-e'
Run the C preprocessor on the text in the region, and show the
result, which includes the expansion of all the macro calls
(`c-macro-expand'). The buffer text before the region is also
included in preprocessing, for the sake of macros defined there,
but the output from this part isn't shown.
When you are debugging C code that uses macros, sometimes it is
hard to figure out precisely how the macros expand. With this
command, you don't have to figure it out; you can see the
expansions.
`C-c C-\'
Insert or align `\' characters at the ends of the lines of the
region (`c-backslash-region'). This is useful after writing or
editing a C macro definition.
If a line already ends in `\', this command adjusts the amount of
whitespace before it. Otherwise, it inserts a new `\'. However,
the last line in the region is treated specially; no `\' is
inserted on that line, and any `\' there is deleted.
`M-x cpp-highlight-buffer'
Highlight parts of the text according to its preprocessor
conditionals. This command displays another buffer named `*CPP
Edit*', which serves as a graphic menu for selecting how to
display particular kinds of conditionals and their contents.
After changing various settings, click on `[A]pply these settings'
(or go to that buffer and type `a') to rehighlight the C mode
buffer accordingly.
`C-c C-s'
Display the syntactic information about the current source line
(`c-show-syntactic-information'). This is the information that
directs how the line is indented.
Comments in C Modes
-------------------
C mode and related modes use a number of variables for controlling
comment format.
`c-comment-only-line-offset'
Extra offset for line which contains only the start of a comment.
It can be either an integer or a cons cell of the form
`(NON-ANCHORED-OFFSET . ANCHORED-OFFSET)', where
NON-ANCHORED-OFFSET is the amount of offset given to
non-column-zero anchored comment-only lines, and ANCHORED-OFFSET
is the amount of offset to give column-zero anchored comment-only
lines. Just an integer as value is equivalent to `(VAL . 0)'.
`c-comment-start-regexp'
This buffer-local variable specifies how to recognize the start of
a comment.
`c-hanging-comment-ender-p'
If this variable is `nil', `c-fill-paragraph' leaves the comment
terminator of a block comment on a line by itself. The default
value is `t', which puts the comment-end delimiter `*/' at the end
of the last line of the comment text.
`c-hanging-comment-starter-p'
If this variable is `nil', `c-fill-paragraph' leaves the starting
delimiter of a block comment on a line by itself. The default
value is `t', which puts the comment-start delimiter `/*' at the
beginning of the first line of the comment text.
Fortran Mode
============
Fortran mode provides special motion commands for Fortran statements
and subprograms, and indentation commands that understand Fortran
conventions of nesting, line numbers and continuation statements.
Fortran mode has its own Auto Fill mode that breaks long lines into
proper Fortran continuation lines.
Special commands for comments are provided because Fortran comments
are unlike those of other languages. Built-in abbrevs optionally save
typing when you insert Fortran keywords.
Use `M-x fortran-mode' to switch to this major mode. This command
runs the hook `fortran-mode-hook' (*note Hooks::.).
Motion Commands
---------------
Fortran mode provides special commands to move by subprograms
(functions and subroutines) and by statements. There is also a command
to put the region around one subprogram, convenient for killing it or
moving it.
`C-M-a'
Move to beginning of subprogram
(`beginning-of-fortran-subprogram').
`C-M-e'
Move to end of subprogram (`end-of-fortran-subprogram').
`C-M-h'
Put point at beginning of subprogram and mark at end
(`mark-fortran-subprogram').
`C-c C-n'
Move to beginning of current or next statement
(`fortran-next-statement').
`C-c C-p'
Move to beginning of current or previous statement
(`fortran-previous-statement').
Fortran Indentation
-------------------
Special commands and features are needed for indenting Fortran code
in order to make sure various syntactic entities (line numbers, comment
line indicators and continuation line flags) appear in the columns that
are required for standard Fortran.
Fortran Indentation Commands
............................
`<TAB>'
Indent the current line (`fortran-indent-line').
`C-j'
Indent the current and start a new indented line
(`fortran-indent-new-line').
`C-M-j'
Break the current line and set up a continuation line.
`M-^'
Join this line to the previous line.
`C-M-q'
Indent all the lines of the subprogram point is in
(`fortran-indent-subprogram').
Fortran mode redefines <TAB> to reindent the current line for
Fortran (`fortran-indent-line'). This command indents line numbers and
continuation markers to their required columns, and independently
indents the body of the statement based on its nesting in the program.
The key `C-j' runs the command `fortran-indent-new-line', which
reindents the current line then makes and indents a new line. This
command is useful to reindent the closing statement of `do' loops and
other blocks before starting a new line.
The key `C-M-q' runs `fortran-indent-subprogram', a command to
reindent all the lines of the Fortran subprogram (function or
subroutine) containing point.
The key `C-M-j' runs `fortran-split-line', which splits a line in
the appropriate fashion for Fortran. In a non-comment line, the second
half becomes a continuation line and is indented accordingly. In a
comment line, both halves become separate comment lines.
`M-^' runs the command `fortran-join-line', which is more or less
the inverse of `fortran-split-line'. It joins the current line to the
previous line in a suitable way for Fortran code.
Continuation Lines
..................
Most modern Fortran compilers allow two ways of writing continuation
lines. If the first non-space character on a line is in column 5, then
that line is a continuation of the previous line. We call this "fixed
format". (In GNU Emacs we always count columns from 0.) The variable
`fortran-continuation-string' specifies what character to put on column
5. A line that starts with a tab character followed by any digit
except `0' is also a continuation line. We call this style of
continuation "tab format".
Fortran mode can make either style of continuation line, but you
must specify which one you prefer. The value of the variable
`indent-tabs-mode' controls the choice: `nil' for fixed format, and
non-`nil' for tab format. You can tell which style is presently in
effect by the presence or absence of the string `Tab' in the mode line.
If the text on a line starts with the conventional Fortran
continuation marker `$', or if it begins with any non-whitespace
character in column 5, Fortran mode treats it as a continuation line.
When you indent a continuation line with <TAB>, it converts the line to
the current continuation style. When you split a Fortran statement
with `C-M-j', the continuation marker on the newline is created
according to the continuation style.
The setting of continuation style affects several other aspects of
editing in Fortran mode. In fixed format mode, the minimum column
number for the body of a statement is 6. Lines inside of Fortran
blocks that are indented to larger column numbers always use only the
space character for whitespace. In tab format mode, the minimum column
number for the statement body is 8, and the whitespace before column 8
must always consist of one tab character.
When you enter Fortran mode for an existing file, it tries to deduce
the proper continuation style automatically from the file contents.
The first line that begins with either a tab character or six spaces
determines the choice. The variable `fortran-analyze-depth' specifies
how many lines to consider (at the beginning of the file); if none of
those lines indicates a style, then the variable
`fortran-tab-mode-default' specifies the style. If it is `nil', that
specifies fixed format, and non-`nil' specifies tab format.
Line Numbers
............
If a number is the first non-whitespace in the line, Fortran
indentation assumes it is a line number and moves it to columns 0
through 4. (Columns always count from 0 in GNU Emacs.)
Line numbers of four digits or less are normally indented one space.
The variable `fortran-line-number-indent' controls this; it specifies
the maximum indentation a line number can have. Line numbers are
indented to right-justify them to end in column 4 unless that would
require more than this maximum indentation. The default value of the
variable is 1.
Simply inserting a line number is enough to indent it according to
these rules. As each digit is inserted, the indentation is recomputed.
To turn off this feature, set the variable
`fortran-electric-line-number' to `nil'. Then inserting line numbers
is like inserting anything else.
Syntactic Conventions
.....................
Fortran mode assumes that you follow certain conventions that
simplify the task of understanding a Fortran program well enough to
indent it properly:
* Two nested `do' loops never share a `continue' statement.
* Fortran keywords such as `if', `else', `then', `do' and others are
written without embedded whitespace or line breaks.
Fortran compilers generally ignore whitespace outside of string
constants, but Fortran mode does not recognize these keywords if
they are not contiguous. Constructs such as `else if' or `end do'
are acceptable, but the second word should be on the same line as
the first and not on a continuation line.
If you fail to follow these conventions, the indentation commands may
indent some lines unaesthetically. However, a correct Fortran program
retains its meaning when reindented even if the conventions are not
followed.
Variables for Fortran Indentation
.................................
Several additional variables control how Fortran indentation works:
`fortran-do-indent'
Extra indentation within each level of `do' statement (default 3).
`fortran-if-indent'
Extra indentation within each level of `if' statement (default 3).
This value is also used for extra indentation within each level of
the Fortran 90 `where' statement.
`fortran-structure-indent'
Extra indentation within each level of `structure', `union', or
`map' statements (default 3).
`fortran-continuation-indent'
Extra indentation for bodies of continuation lines (default 5).
`fortran-check-all-num-for-matching-do'
If this is `nil', indentation assumes that each `do' statement
ends on a `continue' statement. Therefore, when computing
indentation for a statement other than `continue', it can save time
by not checking for a `do' statement ending there. If this is
non-`nil', indenting any numbered statement must check for a `do'
that ends there. The default is `nil'.
`fortran-blink-matching-if'
If this is `t', indenting an `endif' statement moves the cursor
momentarily to the matching `if' statement to show where it is.
The default is `nil'.
`fortran-minimum-statement-indent-fixed'
Minimum indentation for fortran statements when using fixed format
continuation line style. Statement bodies are never indented less
than this much. The default is 6.
`fortran-minimum-statement-indent-tab'
Minimum indentation for fortran statements for tab format
continuation line style. Statement bodies are never indented less
than this much. The default is 8.
Fortran Comments
----------------
The usual Emacs comment commands assume that a comment can follow a
line of code. In Fortran, the standard comment syntax requires an
entire line to be just a comment. Therefore, Fortran mode replaces the
standard Emacs comment commands and defines some new variables.
Fortran mode can also handle a nonstandard comment syntax where
comments start with `!' and can follow other text. Because only some
Fortran compilers accept this syntax, Fortran mode will not insert such
comments unless you have said in advance to do so. To do this, set the
variable `comment-start' to `"!"' (*note Variables::.).
`M-;'
Align comment or insert new comment (`fortran-comment-indent').
`C-x ;'
Applies to nonstandard `!' comments only.
`C-c ;'
Turn all lines of the region into comments, or (with argument)
turn them back into real code (`fortran-comment-region').
`M-;' in Fortran mode is redefined as the command
`fortran-comment-indent'. Like the usual `M-;' command, this
recognizes any kind of existing comment and aligns its text
appropriately; if there is no existing comment, a comment is inserted
and aligned. But inserting and aligning comments are not the same in
Fortran mode as in other modes.
When a new comment must be inserted, if the current line is blank, a
full-line comment is inserted. On a non-blank line, a nonstandard `!'
comment is inserted if you have said you want to use them. Otherwise a
full-line comment is inserted on a new line before the current line.
Nonstandard `!' comments are aligned like comments in other
languages, but full-line comments are different. In a standard
full-line comment, the comment delimiter itself must always appear in
column zero. What can be aligned is the text within the comment. You
can choose from three styles of alignment by setting the variable
`fortran-comment-indent-style' to one of these values:
`fixed'
Align the text at a fixed column, which is the sum of
`fortran-comment-line-extra-indent' and the minimum statement
indentation. This is the default.
The minimum statement indentation is
`fortran-minimum-statement-indent-fixed' for fixed format
continuation line style and `fortran-minimum-statement-indent-tab'
for tab format style.
`relative'
Align the text as if it were a line of code, but with an additional
`fortran-comment-line-extra-indent' columns of indentation.
`nil'
Don't move text in full-line comments automatically at all.
In addition, you can specify the character to be used to indent
within full-line comments by setting the variable
`fortran-comment-indent-char' to the single-character string you want
to use.
Fortran mode introduces two variables `comment-line-start' and
`comment-line-start-skip', which play for full-line comments the same
roles played by `comment-start' and `comment-start-skip' for ordinary
text-following comments. Normally these are set properly by Fortran
mode, so you do not need to change them.
The normal Emacs comment command `C-x ;' has not been redefined. If
you use `!' comments, this command can be used with them. Otherwise it
is useless in Fortran mode.
The command `C-c ;' (`fortran-comment-region') turns all the lines
of the region into comments by inserting the string `C$$$' at the front
of each one. With a numeric argument, it turns the region back into
live code by deleting `C$$$' from the front of each line in it. The
string used for these comments can be controlled by setting the
variable `fortran-comment-region'. Note that here we have an example
of a command and a variable with the same name; these two uses of the
name never conflict because in Lisp and in Emacs it is always clear
from the context which one is meant.
Fortran Auto Fill Mode
----------------------
Fortran Auto Fill mode is a minor mode which automatically splits
Fortran statements as you insert them when they become too wide.
Splitting a statement involves making continuation lines using
`fortran-continuation-string' (*note ForIndent Cont::.). This
splitting happens when you type <SPC>, <RET>, or <TAB>, and also in the
Fortran indentation commands.
`M-x fortran-auto-fill-mode' turns Fortran Auto Fill mode on if it
was off, or off if it was on. This command works the same as `M-x
auto-fill-mode' does for normal Auto Fill mode (*note Filling::.). A
positive numeric argument turns Fortran Auto Fill mode on, and a
negative argument turns it off. You can see when Fortran Auto Fill mode
is in effect by the presence of the word `Fill' in the mode line,
inside the parentheses. Fortran Auto Fill mode is a minor mode, turned
on or off for each buffer individually. *Note Minor Modes::.
Fortran Auto Fill mode breaks lines at spaces or delimiters when the
lines get longer than the desired width (the value of `fill-column').
The delimiters that Fortran Auto Fill mode may break at are `,', `'',
`+', `-', `/', `*', `=', and `)'. The line break comes after the
delimiter if the variable `fortran-break-before-delimiters' is `nil'.
Otherwise (and by default), the break comes before the delimiter.
By default, Fortran Auto Fill mode is not enabled. If you want this
feature turned on permanently, add a hook function to
`fortran-mode-hook' to execute `(fortran-auto-fill-mode 1)'. *Note
Hooks::.
Checking Columns in Fortran
---------------------------
`C-c C-r'
Display a "column ruler" momentarily above the current line
(`fortran-column-ruler').
`C-c C-w'
Split the current window horizontally temporarily so that it is 72
columns wide. This may help you avoid making lines longer than the
72-character limit that some Fortran compilers impose
(`fortran-window-create-momentarily').
The command `C-c C-r' (`fortran-column-ruler') shows a column ruler
momentarily above the current line. The comment ruler is two lines of
text that show you the locations of columns with special significance in
Fortran programs. Square brackets show the limits of the columns for
line numbers, and curly brackets show the limits of the columns for the
statement body. Column numbers appear above them.
Note that the column numbers count from zero, as always in GNU Emacs.
As a result, the numbers may be one less than those you are familiar
with; but the positions they indicate in the line are standard for
Fortran.
The text used to display the column ruler depends on the value of
the variable `indent-tabs-mode'. If `indent-tabs-mode' is `nil', then
the value of the variable `fortran-column-ruler-fixed' is used as the
column ruler. Otherwise, the variable `fortran-column-ruler-tab' is
displayed. By changing these variables, you can change the column
ruler display.
For even more help, use `C-c C-w' (`fortran-window-create'), a
command which splits the current window horizontally, making a window 72
columns wide. By editing in this window you can immediately see when
you make a line too wide to be correct Fortran.
Fortran Keyword Abbrevs
-----------------------
Fortran mode provides many built-in abbrevs for common keywords and
declarations. These are the same sort of abbrev that you can define
yourself. To use them, you must turn on Abbrev mode. *Note Abbrevs::.
The built-in abbrevs are unusual in one way: they all start with a
semicolon. You cannot normally use semicolon in an abbrev, but Fortran
mode makes this possible by changing the syntax of semicolon to "word
constituent."
For example, one built-in Fortran abbrev is `;c' for `continue'. If
you insert `;c' and then insert a punctuation character such as a space
or a newline, the `;c' expands automatically to `continue', provided
Abbrev mode is enabled.
Type `;?' or `;C-h' to display a list of all the built-in Fortran
abbrevs and what they stand for.
Other Fortran Mode Commands
---------------------------
`C-x n d'
Narrow to the current Fortran subprogram.
Fortran mode redefines the key `C-x n d' to run the command
`fortran-narrow-to-subprogram', which is the Fortran analogue of the
key's usual definition. It narrows the buffer to the subprogram
containing point.
Asm Mode
========
Asm mode is a major mode for editing files of assembler code. It
defines these commands:
`<TAB>'
`tab-to-tab-stop'.
`C-j'
Insert a newline and then indent using `tab-to-tab-stop'.
`:'
Insert a colon and then remove the indentation from before the
label preceding colon. Then do `tab-to-tab-stop'.
`;'
Insert or align a comment.
The variable `asm-comment-char' specifies which character starts
comments in assembler syntax.
Compiling and Testing Programs
******************************
The previous chapter discusses the Emacs commands that are useful for
making changes in programs. This chapter deals with commands that
assist in the larger process of developing and maintaining programs.
Running Compilations under Emacs
================================
Emacs can run compilers for noninteractive languages such as C and
Fortran as inferior processes, feeding the error log into an Emacs
buffer. It can also parse the error messages and show you the source
lines where compilation errors occurred.
`M-x compile'
Run a compiler asynchronously under Emacs, with error messages to
`*compilation*' buffer.
`M-x grep'
Run `grep' asynchronously under Emacs, with matching lines listed
in the buffer named `*grep*'.
`M-x grep-find'
Run `grep' via `find', with user-specified arguments, and collect
output in the buffer named `*grep*'.
`M-x kill-compilation'
`M-x kill-grep'
Kill the running compilation or `grep' subprocess.
To run `make' or another compilation command, do `M-x compile'.
This command reads a shell command line using the minibuffer, and then
executes the command in an inferior shell, putting output in the buffer
named `*compilation*'. The current buffer's default directory is used
as the working directory for the execution of the command; normally,
therefore, the compilation happens in this directory.
When the shell command line is read, the minibuffer appears
containing a default command line, which is the command you used the
last time you did `M-x compile'. If you type just <RET>, the same
command line is used again. For the first `M-x compile', the default is
`make -k'. The default compilation command comes from the variable
`compile-command'; if the appropriate compilation command for a file is
something other than `make -k', it can be useful for the file to
specify a local value for `compile-command' (*note File Variables::.).
Starting a compilation displays the buffer `*compilation*' in
another window but does not select it. The buffer's mode line tells you
whether compilation is finished, with the word `run' or `exit' inside
the parentheses. You do not have to keep this buffer visible;
compilation continues in any case. While a compilation is going on, the
string `Compiling' appears in the mode lines of all windows. When this
string disappears, the compilation is finished.
If you want to watch the compilation transcript as it appears, switch
to the `*compilation*' buffer and move point to the end of the buffer.
When point is at the end, new compilation output is inserted above
point, which remains at the end. If point is not at the end of the
buffer, it remains fixed while more compilation output is added at the
end of the buffer.
If you set the variable `compilation-scroll-output' to a non-`nil'
value, then the compilation buffer always scrolls to follow output as
it comes in.
To kill the compilation process, do `M-x kill-compilation'. When
the compiler process terminates, the mode line of the `*compilation*'
buffer changes to say `signal' instead of `run'. Starting a new
compilation also kills any running compilation, as only one can exist
at any time. However, `M-x compile' asks for confirmation before
actually killing a compilation that is running.
Searching with Grep under Emacs
===============================
Just as you can run a compiler from Emacs and then visit the lines
where there were compilation errors, you can also run `grep' and then
visit the lines on which matches were found. This works by treating
the matches reported by `grep' as if they were "errors."
To do this, type `M-x grep', then enter a command line that
specifies how to run `grep'. Use the same arguments you would give
`grep' when running it normally: a `grep'-style regexp (usually in
single-quotes to quote the shell's special characters) followed by file
names, which may use wildcards. The output from `grep' goes in the
`*grep*' buffer. You can find the corresponding lines in the original
files using `C-x `' and <RET>, as with compilation errors.
If you specify a prefix argument for `M-x grep', it figures out the
tag (*note Tags::.) around point, and puts that into the default `grep'
command.
The command `M-x grep-find' is similar to `M-x grep', but it
supplies a different initial default for the command--one that runs
both `find' and `grep', so as to search every file in a directory tree.
See also the `find-grep-dired' command, in *Note Dired and Find::.
Compilation Mode
================
The `*compilation*' buffer uses a special major mode, Compilation
mode, whose main feature is to provide a convenient way to look at the
source line where the error happened.
`C-x `'
Visit the locus of the next compiler error message or `grep' match.
`<RET>'
Visit the locus of the error message that point is on. This
command is used in the compilation buffer.
`Mouse-2'
Visit the locus of the error message that you click on.
You can visit the source for any particular error message by moving
point in `*compilation*' to that error message and typing <RET>
(`compile-goto-error'). Or click `Mouse-2' on the error message; you
need not switch to the `*compilation*' buffer first.
To parse the compiler error messages sequentially, type `C-x `'
(`next-error'). The character following the `C-x' is the backquote or
"grave accent," not the single-quote. This command is available in all
buffers, not just in `*compilation*'; it displays the next error
message at the top of one window and source location of the error in
another window.
The first time `C-x `' is used after the start of a compilation, it
moves to the first error's location. Subsequent uses of `C-x `'
advance down to subsequent errors. If you visit a specific error
message with <RET> or `Mouse-2', subsequent `C-x `' commands advance
from there. When `C-x `' gets to the end of the buffer and finds no
more error messages to visit, it fails and signals an Emacs error.
`C-u C-x `' starts scanning from the beginning of the compilation
buffer. This is one way to process the same set of errors again.
Compilation mode also redefines the keys <SPC> and <DEL> to scroll
by screenfuls, and `M-n' and `M-p' to move to the next or previous
error message. You can also use `M-{' and `M-}' to move up or down to
an error message for a different source file.
The features of Compilation mode are also available in a minor mode
called Compilation Minor mode. This lets you parse error messages in
any buffer, not just a normal compilation output buffer. Type `M-x
compilation-minor-mode' to enable the minor mode. This defines the keys
<RET> and `Mouse-2', as in the Compilation major mode.
Compilation minor mode works in any buffer, as long as the contents
are in a format that it understands. In an Rlogin buffer (*note Remote
Host::.), Compilation minor mode automatically accesses remote source
files by FTP (*note File Names::.).
Subshells for Compilation
=========================
Emacs uses a shell to run the compilation command, but specifies the
option for a noninteractive shell. This means, in particular, that the
shell should start with no prompt. If you find your usual shell prompt
making an unsightly appearance in the `*compilation*' buffer, it means
you have made a mistake in your shell's init file by setting the prompt
unconditionally. (This init file's name may be `.bashrc', `.profile',
`.cshrc', `.shrc', or various other things, depending on the shell you
use.) The shell init file should set the prompt only if there already
is a prompt. In csh, here is how to do it:
if ($?prompt) set prompt = ...
And here's how to do it in bash:
if [ "${PS1+set}" = set ]
then PS1=...
fi
There may well be other things that your shell's init file ought to
do only for an interactive shell. You can use the same method to
conditionalize them.
The MS-DOS "operating system" does not support asynchronous
subprocesses; to work around this lack, `M-x compile' runs the
compilation command synchronously on MS-DOS. As a consequence, you must
wait until the command finishes before you can do anything else in
Emacs. *Note MS-DOS::.
Running Debuggers Under Emacs
=============================
The GUD (Grand Unified Debugger) library provides an interface to
various symbolic debuggers from within Emacs. We recommend the debugger
GDB, which is free software, but you can also run DBX, SDB or XDB if you
have them. GUD can also serve as an interface to the Perl's debugging
mode, the Python debugger PDB, and to JDB, the Java Debugger.
Starting GUD
------------
There are several commands for starting a debugger, each
corresponding to a particular debugger program.
`M-x gdb <RET> FILE <RET>'
Run GDB as a subprocess of Emacs. This command creates a buffer
for input and output to GDB, and switches to it. If a GDB buffer
already exists, it just switches to that buffer.
`M-x dbx <RET> FILE <RET>'
Similar, but run DBX instead of GDB.
`M-x xdb <RET> FILE <RET>'
Similar, but run XDB instead of GDB. Use the variable
`gud-xdb-directories' to specify directories to search for source
files.
`M-x sdb <RET> FILE <RET>'
Similar, but run SDB instead of GDB.
Some versions of SDB do not mention source file names in their
messages. When you use them, you need to have a valid tags table
(*note Tags::.) in order for GUD to find functions in the source
code. If you have not visited a tags table or the tags table
doesn't list one of the functions, you get a message saying `The
sdb support requires a valid tags table to work'. If this
happens, generate a valid tags table in the working directory and
try again.
`M-x perldb <RET> FILE <RET>'
Run the Perl interpreter in debug mode to debug FILE, a Perl
program.
`M-x jdb <RET> FILE <RET>'
Run the Java debugger to debug FILE.
`M-x pdb <RET> FILE <RET>'
Run the Python debugger to debug FILE.
Each of these commands takes one argument: a command line to invoke
the debugger. In the simplest case, specify just the name of the
executable file you want to debug. You may also use options that the
debugger supports. However, shell wildcards and variables are not
allowed. GUD assumes that the first argument not starting with a `-'
is the executable file name.
Emacs can only run one debugger process at a time.
Debugger Operation
------------------
When you run a debugger with GUD, the debugger uses an Emacs buffer
for its ordinary input and output. This is called the GUD buffer. The
debugger displays the source files of the program by visiting them in
Emacs buffers. An arrow (`=>') in one of these buffers indicates the
current execution line. Moving point in this buffer does not move the
arrow.
You can start editing these source files at any time in the buffers
that were made to display them. The arrow is not part of the file's
text; it appears only on the screen. If you do modify a source file,
keep in mind that inserting or deleting lines will throw off the arrow's
positioning; GUD has no way of figuring out which line corresponded
before your changes to the line number in a debugger message. Also,
you'll typically have to recompile and restart the program for your
changes to be reflected in the debugger's tables.
If you wish, you can control your debugger process entirely through
the debugger buffer, which uses a variant of Shell mode. All the usual
commands for your debugger are available, and you can use the Shell mode
history commands to repeat them. *Note Shell Mode::.
Commands of GUD
---------------
The GUD interaction buffer uses a variant of Shell mode, so the
commands of Shell mode are available (*note Shell Mode::.). GUD mode
also provides commands for setting and clearing breakpoints, for
selecting stack frames, and for stepping through the program. These
commands are available both in the GUD buffer and globally, but with
different key bindings.
The breakpoint commands are usually used in source file buffers,
because that is the way to specify where to set or clear the breakpoint.
Here's the global command to set a breakpoint:
`C-x <SPC>'
Set a breakpoint on the source line that point is on.
Here are the other special commands provided by GUD. The keys
starting with `C-c' are available only in the GUD interaction buffer.
The key bindings that start with `C-x C-a' are available in the GUD
interaction buffer and also in source files.
`C-c C-l'
`C-x C-a C-l'
Display in another window the last line referred to in the GUD
buffer (that is, the line indicated in the last location message).
This runs the command `gud-refresh'.
`C-c C-s'
`C-x C-a C-s'
Execute a single line of code (`gud-step'). If the line contains
a function call, execution stops after entering the called
function.
`C-c C-n'
`C-x C-a C-n'
Execute a single line of code, stepping across entire function
calls at full speed (`gud-next').
`C-c C-i'
`C-x C-a C-i'
Execute a single machine instruction (`gud-stepi').
`C-c C-r'
`C-x C-a C-r'
Continue execution without specifying any stopping point. The
program will run until it hits a breakpoint, terminates, or gets a
signal that the debugger is checking for (`gud-cont').
`C-c C-d'
`C-x C-a C-d'
Delete the breakpoint(s) on the current source line, if any
(`gud-remove'). If you use this command in the GUD interaction
buffer, it applies to the line where the program last stopped.
`C-c C-t'
`C-x C-a C-t'
Set a temporary breakpoint on the current source line, if any. If
you use this command in the GUD interaction buffer, it applies to
the line where the program last stopped.
The above commands are common to all supported debuggers. If you are
using GDB or (some versions of) DBX, these additional commands are
available:
`C-c <'
`C-x C-a <'
Select the next enclosing stack frame (`gud-up'). This is
equivalent to the `up' command.
`C-c >'
`C-x C-a >'
Select the next inner stack frame (`gud-down'). This is
equivalent to the `down' command.
If you are using GDB, these additional key bindings are available:
`<TAB>'
With GDB, complete a symbol name (`gud-gdb-complete-command').
This key is available only in the GUD interaction buffer, and
requires GDB versions 4.13 and later.
`C-c C-f'
`C-x C-a C-f'
Run the program until the selected stack frame returns (or until it
stops for some other reason).
These commands interpret a numeric argument as a repeat count, when
that makes sense.
Because <TAB> serves as a completion command, you can't use it to
enter a tab as input to the program you are debugging with GDB.
Instead, type `C-q <TAB>' to enter a tab.
GUD Customization
-----------------
On startup, GUD runs one of the following hooks: `gdb-mode-hook', if
you are using GDB; `dbx-mode-hook', if you are using DBX;
`sdb-mode-hook', if you are using SDB; `xdb-mode-hook', if you are
using XDB; `perldb-mode-hook', for Perl debugging mode;
`jdb-mode-hook', for PDB; `jdb-mode-hook', for JDB. You can use these
hooks to define custom key bindings for the debugger interaction
buffer. *Note Hooks::.
Here is a convenient way to define a command that sends a particular
command string to the debugger, and set up a key binding for it in the
debugger interaction buffer:
(gud-def FUNCTION CMDSTRING BINDING DOCSTRING)
This defines a command named FUNCTION which sends CMDSTRING to the
debugger process, and gives it the documentation string DOCSTRING. You
can use the command thus defined in any buffer. If BINDING is
non-`nil', `gud-def' also binds the command to `C-c BINDING' in the GUD
buffer's mode and to `C-x C-a BINDING' generally.
The command string CMDSTRING may contain certain `%'-sequences that
stand for data to be filled in at the time FUNCTION is called:
`%f'
The name of the current source file. If the current buffer is the
GUD buffer, then the "current source file" is the file that the
program stopped in.
`%l'
The number of the current source line. If the current buffer is
the GUD buffer, then the "current source line" is the line that
the program stopped in.
`%e'
The text of the C lvalue or function-call expression at or
adjacent to point.
`%a'
The text of the hexadecimal address at or adjacent to point.
`%p'
The numeric argument of the called function, as a decimal number.
If the command is used without a numeric argument, `%p' stands for
the empty string.
If you don't use `%p' in the command string, the command you define
ignores any numeric argument.
Executing Lisp Expressions
==========================
Emacs has several different major modes for Lisp and Scheme. They
are the same in terms of editing commands, but differ in the commands
for executing Lisp expressions. Each mode has its own purpose.
Emacs-Lisp mode
The mode for editing source files of programs to run in Emacs Lisp.
This mode defines `C-M-x' to evaluate the current defun. *Note
Lisp Libraries::.
Lisp Interaction mode
The mode for an interactive session with Emacs Lisp. It defines
`C-j' to evaluate the sexp before point and insert its value in the
buffer. *Note Lisp Interaction::.
Lisp mode
The mode for editing source files of programs that run in Lisps
other than Emacs Lisp. This mode defines `C-M-x' to send the
current defun to an inferior Lisp process. *Note External Lisp::.
Inferior Lisp mode
The mode for an interactive session with an inferior Lisp process.
This mode combines the special features of Lisp mode and Shell mode
(*note Shell Mode::.).
Scheme mode
Like Lisp mode but for Scheme programs.
Inferior Scheme mode
The mode for an interactive session with an inferior Scheme
process.
Most editing commands for working with Lisp programs are in fact
available globally. *Note Programs::.
Libraries of Lisp Code for Emacs
================================
Lisp code for Emacs editing commands is stored in files whose names
conventionally end in `.el'. This ending tells Emacs to edit them in
Emacs-Lisp mode (*note Executing Lisp::.).
To execute a file of Emacs Lisp code, use `M-x load-file'. This
command reads a file name using the minibuffer and then executes the
contents of that file as Lisp code. It is not necessary to visit the
file first; in any case, this command reads the file as found on disk,
not text in an Emacs buffer.
Once a file of Lisp code is installed in the Emacs Lisp library
directories, users can load it using `M-x load-library'. Programs can
load it by calling `load-library', or with `load', a more primitive
function that is similar but accepts some additional arguments.
`M-x load-library' differs from `M-x load-file' in that it searches
a sequence of directories and tries three file names in each directory.
Suppose your argument is LIB; the three names are `LIB.elc', `LIB.el',
and lastly just `LIB'. If `LIB.elc' exists, it is by convention the
result of compiling `LIB.el'; it is better to load the compiled file,
since it will load and run faster.
If `load-library' finds that `LIB.el' is newer than `LIB.elc' file,
it prints a warning, because it's likely that somebody made changes to
the `.el' file and forgot to recompile it.
Because the argument to `load-library' is usually not in itself a
valid file name, file name completion is not available. Indeed, when
using this command, you usually do not know exactly what file name will
be used.
The sequence of directories searched by `M-x load-library' is
specified by the variable `load-path', a list of strings that are
directory names. The default value of the list contains the directory
where the Lisp code for Emacs itself is stored. If you have libraries
of your own, put them in a single directory and add that directory to
`load-path'. `nil' in this list stands for the current default
directory, but it is probably not a good idea to put `nil' in the list.
If you find yourself wishing that `nil' were in the list, most likely
what you really want to do is use `M-x load-file' this once.
Often you do not have to give any command to load a library, because
the commands defined in the library are set up to "autoload" that
library. Trying to run any of those commands calls `load' to load the
library; this replaces the autoload definitions with the real ones from
the library.
Emacs Lisp code can be compiled into byte-code which loads faster,
takes up less space when loaded, and executes faster. *Note Byte
Compilation: (elisp)Byte Compilation. By convention, the compiled code
for a library goes in a separate file whose name consists of the
library source file with `c' appended. Thus, the compiled code for
`foo.el' goes in `foo.elc'. That's why `load-library' searches for
`.elc' files first.
Evaluating Emacs-Lisp Expressions
=================================
Lisp programs intended to be run in Emacs should be edited in
Emacs-Lisp mode; this happens automatically for file names ending in
`.el'. By contrast, Lisp mode itself is used for editing Lisp programs
intended for other Lisp systems. To switch to Emacs-Lisp mode
explicitly, use the command `M-x emacs-lisp-mode'.
For testing of Lisp programs to run in Emacs, it is often useful to
evaluate part of the program as it is found in the Emacs buffer. For
example, after changing the text of a Lisp function definition,
evaluating the definition installs the change for future calls to the
function. Evaluation of Lisp expressions is also useful in any kind of
editing, for invoking noninteractive functions (functions that are not
commands).
`M-:'
Read a single Lisp expression in the minibuffer, evaluate it, and
print the value in the echo area (`eval-expression').
`C-x C-e'
Evaluate the Lisp expression before point, and print the value in
the echo area (`eval-last-sexp').
`C-M-x'
Evaluate the defun containing or after point, and print the value
in the echo area (`eval-defun').
`M-x eval-region'
Evaluate all the Lisp expressions in the region.
`M-x eval-current-buffer'
Evaluate all the Lisp expressions in the buffer.
`M-:' (`eval-expression') is the most basic command for evaluating a
Lisp expression interactively. It reads the expression using the
minibuffer, so you can execute any expression on a buffer regardless of
what the buffer contains. When the expression is evaluated, the current
buffer is once again the buffer that was current when `M-:' was typed.
In Emacs-Lisp mode, the key `C-M-x' is bound to the command
`eval-defun', which parses the defun containing or following point as a
Lisp expression and evaluates it. The value is printed in the echo
area. This command is convenient for installing in the Lisp environment
changes that you have just made in the text of a function definition.
`C-M-x' treats `defvar' expressions specially. Normally, evaluating
a `defvar' expression does nothing if the variable it defines already
has a value. But `C-M-x' unconditionally resets the variable to the
initial value specified in the `defvar' expression. This special
feature is convenient for debugging Lisp programs.
The command `C-x C-e' (`eval-last-sexp') evaluates the Lisp
expression preceding point in the buffer, and displays the value in the
echo area. It is available in all major modes, not just Emacs-Lisp
mode. It does not treat `defvar' specially.
If `C-M-x', `C-x C-e', or `M-:' is given a numeric argument, it
inserts the value into the current buffer at point, rather than
displaying it in the echo area. The argument's value does not matter.
The most general command for evaluating Lisp expressions from a
buffer is `eval-region'. `M-x eval-region' parses the text of the
region as one or more Lisp expressions, evaluating them one by one.
`M-x eval-current-buffer' is similar but evaluates the entire buffer.
This is a reasonable way to install the contents of a file of Lisp code
that you are just ready to test. Later, as you find bugs and change
individual functions, use `C-M-x' on each function that you change.
This keeps the Lisp world in step with the source file.
Lisp Interaction Buffers
========================
The buffer `*scratch*' which is selected when Emacs starts up is
provided for evaluating Lisp expressions interactively inside Emacs.
The simplest way to use the `*scratch*' buffer is to insert Lisp
expressions and type `C-j' after each expression. This command reads
the Lisp expression before point, evaluates it, and inserts the value
in printed representation before point. The result is a complete
typescript of the expressions you have evaluated and their values.
The `*scratch*' buffer's major mode is Lisp Interaction mode, which
is the same as Emacs-Lisp mode except for the binding of `C-j'.
The rationale for this feature is that Emacs must have a buffer when
it starts up, but that buffer is not useful for editing files since a
new buffer is made for every file that you visit. The Lisp interpreter
typescript is the most useful thing I can think of for the initial
buffer to do. Type `M-x lisp-interaction-mode' to put the current
buffer in Lisp Interaction mode.
An alternative way of evaluating Emacs Lisp expressions interactively
is to use Inferior Emacs-Lisp mode, which provides an interface rather
like Shell mode (*note Shell Mode::.) for evaluating Emacs Lisp
expressions. Type `M-x ielm' to create an `*ielm*' buffer which uses
this mode.
Running an External Lisp
========================
Emacs has facilities for running programs in other Lisp systems.
You can run a Lisp process as an inferior of Emacs, and pass
expressions to it to be evaluated. You can also pass changed function
definitions directly from the Emacs buffers in which you edit the Lisp
programs to the inferior Lisp process.
To run an inferior Lisp process, type `M-x run-lisp'. This runs the
program named `lisp', the same program you would run by typing `lisp'
as a shell command, with both input and output going through an Emacs
buffer named `*lisp*'. That is to say, any "terminal output" from Lisp
will go into the buffer, advancing point, and any "terminal input" for
Lisp comes from text in the buffer. (You can change the name of the
Lisp executable file by setting the variable `inferior-lisp-program'.)
To give input to Lisp, go to the end of the buffer and type the
input, terminated by <RET>. The `*lisp*' buffer is in Inferior Lisp
mode, which combines the special characteristics of Lisp mode with most
of the features of Shell mode (*note Shell Mode::.). The definition of
<RET> to send a line to a subprocess is one of the features of Shell
mode.
For the source files of programs to run in external Lisps, use Lisp
mode. This mode can be selected with `M-x lisp-mode', and is used
automatically for files whose names end in `.l', `.lsp', or `.lisp', as
most Lisp systems usually expect.
When you edit a function in a Lisp program you are running, the
easiest way to send the changed definition to the inferior Lisp process
is the key `C-M-x'. In Lisp mode, this runs the function
`lisp-eval-defun', which finds the defun around or following point and
sends it as input to the Lisp process. (Emacs can send input to any
inferior process regardless of what buffer is current.)
Contrast the meanings of `C-M-x' in Lisp mode (for editing programs
to be run in another Lisp system) and Emacs-Lisp mode (for editing Lisp
programs to be run in Emacs): in both modes it has the effect of
installing the function definition that point is in, but the way of
doing so is different according to where the relevant Lisp environment
is found. *Note Executing Lisp::.
Abbrevs
*******
A defined "abbrev" is a word which "expands", if you insert it, into
some different text. Abbrevs are defined by the user to expand in
specific ways. For example, you might define `foo' as an abbrev
expanding to `find outer otter'. Then you would be able to insert
`find outer otter ' into the buffer by typing `f o o <SPC>'.
A second kind of abbreviation facility is called "dynamic abbrev
expansion". You use dynamic abbrev expansion with an explicit command
to expand the letters in the buffer before point by looking for other
words in the buffer that start with those letters. *Note Dynamic
Abbrevs::.
Abbrev Concepts
===============
An "abbrev" is a word which has been defined to "expand" into a
specified "expansion". When you insert a word-separator character
following the abbrev, that expands the abbrev--replacing the abbrev
with its expansion. For example, if `foo' is defined as an abbrev
expanding to `find outer otter', then you can insert `find outer
otter.' into the buffer by typing `f o o .'.
Abbrevs expand only when Abbrev mode (a minor mode) is enabled.
Disabling Abbrev mode does not cause abbrev definitions to be forgotten,
but they do not expand until Abbrev mode is enabled again. The command
`M-x abbrev-mode' toggles Abbrev mode; with a numeric argument, it
turns Abbrev mode on if the argument is positive, off otherwise. *Note
Minor Modes::. `abbrev-mode' is also a variable; Abbrev mode is on
when the variable is non-`nil'. The variable `abbrev-mode'
automatically becomes local to the current buffer when it is set.
Abbrev definitions can be "mode-specific"--active only in one major
mode. Abbrevs can also have "global" definitions that are active in
all major modes. The same abbrev can have a global definition and
various mode-specific definitions for different major modes. A
mode-specific definition for the current major mode overrides a global
definition.
Abbrevs can be defined interactively during the editing session.
Lists of abbrev definitions can also be saved in files and reloaded in
later sessions. Some users keep extensive lists of abbrevs that they
load in every session.
Defining Abbrevs
================
`C-x a g'
Define an abbrev, using one or more words before point as its
expansion (`add-global-abbrev').
`C-x a l'
Similar, but define an abbrev specific to the current major mode
(`add-mode-abbrev').
`C-x a i g'
Define a word in the buffer as an abbrev
(`inverse-add-global-abbrev').
`C-x a i l'
Define a word in the buffer as a mode-specific abbrev
(`inverse-add-mode-abbrev').
`M-x kill-all-abbrevs'
This command discards all abbrev definitions currently in effect,
leaving a blank slate.
The usual way to define an abbrev is to enter the text you want the
abbrev to expand to, position point after it, and type `C-x a g'
(`add-global-abbrev'). This reads the abbrev itself using the
minibuffer, and then defines it as an abbrev for one or more words
before point. Use a numeric argument to say how many words before
point should be taken as the expansion. For example, to define the
abbrev `foo' as mentioned above, insert the text `find outer otter' and
then type `C-u 3 C-x a g f o o <RET>'.
An argument of zero to `C-x a g' means to use the contents of the
region as the expansion of the abbrev being defined.
The command `C-x a l' (`add-mode-abbrev') is similar, but defines a
mode-specific abbrev. Mode-specific abbrevs are active only in a
particular major mode. `C-x a l' defines an abbrev for the major mode
in effect at the time `C-x a l' is typed. The arguments work the same
as for `C-x a g'.
If the text already in the buffer is the abbrev, rather than its
expansion, use command `C-x a i g' (`inverse-add-global-abbrev')
instead of `C-x a g', or use `C-x a i l' (`inverse-add-mode-abbrev')
instead of `C-x a l'. These commands are called "inverse" because they
invert the meaning of the two text strings they use (one from the
buffer and one read with the minibuffer).
To change the definition of an abbrev, just define a new definition.
When the abbrev has a prior definition, the abbrev definition commands
ask for confirmation for replacing it.
To remove an abbrev definition, give a negative argument to the
abbrev definition command: `C-u - C-x a g' or `C-u - C-x a l'. The
former removes a global definition, while the latter removes a
mode-specific definition.
`M-x kill-all-abbrevs' removes all the abbrev definitions there are,
both global and local.
Controlling Abbrev Expansion
============================
An abbrev expands whenever it is present in the buffer just before
point and you type a self-inserting whitespace or punctuation character
(<SPC>, comma, etc.). More precisely, any character that is not a word
constituent expands an abbrev, and any word-constituent character can
be part of an abbrev. The most common way to use an abbrev is to
insert it and then insert a punctuation character to expand it.
Abbrev expansion preserves case; thus, `foo' expands into `find
outer otter'; `Foo' into `Find outer otter', and `FOO' into `FIND OUTER
OTTER' or `Find Outer Otter' according to the variable
`abbrev-all-caps' (a non-`nil' value chooses the first of the two
expansions).
These commands are used to control abbrev expansion:
`M-''
Separate a prefix from a following abbrev to be expanded
(`abbrev-prefix-mark').
`C-x a e'
Expand the abbrev before point (`expand-abbrev'). This is
effective even when Abbrev mode is not enabled.
`M-x expand-region-abbrevs'
Expand some or all abbrevs found in the region.
You may wish to expand an abbrev with a prefix attached; for example,
if `cnst' expands into `construction', you might want to use it to
enter `reconstruction'. It does not work to type `recnst', because
that is not necessarily a defined abbrev. What you can do is use the
command `M-'' (`abbrev-prefix-mark') in between the prefix `re' and the
abbrev `cnst'. First, insert `re'. Then type `M-''; this inserts a
hyphen in the buffer to indicate that it has done its work. Then
insert the abbrev `cnst'; the buffer now contains `re-cnst'. Now
insert a non-word character to expand the abbrev `cnst' into
`construction'. This expansion step also deletes the hyphen that
indicated `M-'' had been used. The result is the desired
`reconstruction'.
If you actually want the text of the abbrev in the buffer, rather
than its expansion, you can accomplish this by inserting the following
punctuation with `C-q'. Thus, `foo C-q ,' leaves `foo,' in the buffer.
If you expand an abbrev by mistake, you can undo the expansion and
bring back the abbrev itself by typing `C-_' to undo (*note Undo::.).
This also undoes the insertion of the non-word character that expanded
the abbrev. If the result you want is the terminating non-word
character plus the unexpanded abbrev, you must reinsert the terminating
character, quoting it with `C-q'. You can also use the command `M-x
unexpand-abbrev' to cancel the last expansion without deleting the
terminating character.
`M-x expand-region-abbrevs' searches through the region for defined
abbrevs, and for each one found offers to replace it with its expansion.
This command is useful if you have typed in text using abbrevs but
forgot to turn on Abbrev mode first. It may also be useful together
with a special set of abbrev definitions for making several global
replacements at once. This command is effective even if Abbrev mode is
not enabled.
Expanding an abbrev runs the hook `pre-abbrev-expand-hook' (*note
Hooks::.).
Examining and Editing Abbrevs
=============================
`M-x list-abbrevs'
Display a list of all abbrev definitions.
`M-x edit-abbrevs'
Edit a list of abbrevs; you can add, alter or remove definitions.
The output from `M-x list-abbrevs' looks like this:
(lisp-mode-abbrev-table)
"dk" 0 "define-key"
(global-abbrev-table)
"dfn" 0 "definition"
(Some blank lines of no semantic significance, and some other abbrev
tables, have been omitted.)
A line containing a name in parentheses is the header for abbrevs in
a particular abbrev table; `global-abbrev-table' contains all the global
abbrevs, and the other abbrev tables that are named after major modes
contain the mode-specific abbrevs.
Within each abbrev table, each nonblank line defines one abbrev. The
word at the beginning of the line is the abbrev. The number that
follows is the number of times the abbrev has been expanded. Emacs
keeps track of this to help you see which abbrevs you actually use, so
that you can eliminate those that you don't use often. The string at
the end of the line is the expansion.
`M-x edit-abbrevs' allows you to add, change or kill abbrev
definitions by editing a list of them in an Emacs buffer. The list has
the same format described above. The buffer of abbrevs is called
`*Abbrevs*', and is in Edit-Abbrevs mode. Type `C-c C-c' in this
buffer to install the abbrev definitions as specified in the
buffer--and delete any abbrev definitions not listed.
The command `edit-abbrevs' is actually the same as `list-abbrevs'
except that it selects the buffer `*Abbrevs*' whereas `list-abbrevs'
merely displays it in another window.
Saving Abbrevs
==============
These commands allow you to keep abbrev definitions between editing
sessions.
`M-x write-abbrev-file <RET> FILE <RET>'
Write a file FILE describing all defined abbrevs.
`M-x read-abbrev-file <RET> FILE <RET>'
Read the file FILE and define abbrevs as specified therein.
`M-x quietly-read-abbrev-file <RET> FILE <RET>'
Similar but do not display a message about what is going on.
`M-x define-abbrevs'
Define abbrevs from definitions in current buffer.
`M-x insert-abbrevs'
Insert all abbrevs and their expansions into current buffer.
`M-x write-abbrev-file' reads a file name using the minibuffer and
then writes a description of all current abbrev definitions into that
file. This is used to save abbrev definitions for use in a later
session. The text stored in the file is a series of Lisp expressions
that, when executed, define the same abbrevs that you currently have.
`M-x read-abbrev-file' reads a file name using the minibuffer and
then reads the file, defining abbrevs according to the contents of the
file. `M-x quietly-read-abbrev-file' is the same except that it does
not display a message in the echo area saying that it is doing its
work; it is actually useful primarily in the `.emacs' file. If an
empty argument is given to either of these functions, they use the file
name specified in the variable `abbrev-file-name', which is by default
`"~/.abbrev_defs"'.
Emacs will offer to save abbrevs automatically if you have changed
any of them, whenever it offers to save all files (for `C-x s' or `C-x
C-c'). This feature can be inhibited by setting the variable
`save-abbrevs' to `nil'.
The commands `M-x insert-abbrevs' and `M-x define-abbrevs' are
similar to the previous commands but work on text in an Emacs buffer.
`M-x insert-abbrevs' inserts text into the current buffer before point,
describing all current abbrev definitions; `M-x define-abbrevs' parses
the entire current buffer and defines abbrevs accordingly.
Dynamic Abbrev Expansion
========================
The abbrev facility described above operates automatically as you
insert text, but all abbrevs must be defined explicitly. By contrast,
"dynamic abbrevs" allow the meanings of abbrevs to be determined
automatically from the contents of the buffer, but dynamic abbrev
expansion happens only when you request it explicitly.
`M-/'
Expand the word in the buffer before point as a "dynamic abbrev",
by searching in the buffer for words starting with that
abbreviation (`dabbrev-expand').
`C-M-/'
Complete the word before point as a dynamic abbrev
(`dabbrev-completion').
For example, if the buffer contains `does this follow ' and you type
`f o M-/', the effect is to insert `follow' because that is the last
word in the buffer that starts with `fo'. A numeric argument to `M-/'
says to take the second, third, etc. distinct expansion found looking
backward from point. Repeating `M-/' searches for an alternative
expansion by looking farther back. After scanning all the text before
point, it searches the text after point. The variable `dabbrev-limit',
if non-`nil', specifies how far in the buffer to search for an
expansion.
After scanning the current buffer, `M-/' normally searches other
buffers, unless you have set `dabbrev-check-all-buffers' to `nil'.
A negative argument to `M-/', as in `C-u - M-/', says to search
first for expansions after point, and second for expansions before
point. If you repeat the `M-/' to look for another expansion, do not
specify an argument. This tries all the expansions after point and
then the expansions before point.
After you have expanded a dynamic abbrev, you can copy additional
words that follow the expansion in its original context. Simply type
`<SPC> M-/' for each word you want to copy. The spacing and
punctuation between words is copied along with the words.
The command `C-M-/' (`dabbrev-completion') performs completion of a
dynamic abbreviation. Instead of trying the possible expansions one by
one, it finds all of them, then inserts the text that they have in
common. If they have nothing in common, `C-M-/' displays a list of
completions, from which you can select a choice in the usual manner.
*Note Completion::.
Dynamic abbrev expansion is completely independent of Abbrev mode;
the expansion of a word with `M-/' is completely independent of whether
it has a definition as an ordinary abbrev.
Customizing Dynamic Abbreviation
================================
Normally, dynamic abbrev expansion ignores case when searching for
expansions. That is, the expansion need not agree in case with the word
you are expanding.
This feature is controlled by the variable
`dabbrev-case-fold-search'. If it is `t', case is ignored in this
search; if `nil', the word and the expansion must match in case. If
the value of `dabbrev-case-fold-search' is `case-fold-search', which is
true by default, then the variable `case-fold-search' controls whether
to ignore case while searching for expansions.
Normally, dynamic abbrev expansion preserves the case pattern *of
the abbrev you have typed*, by converting the expansion to that case
pattern.
The variable `dabbrev-case-replace' controls whether to preserve the
case pattern of the abbrev. If it is `t', the abbrev's case pattern is
preserved in most cases; if `nil', the expansion is always copied
verbatim. If the value of `dabbrev-case-replace' is `case-replace',
which is true by default, then the variable `case-replace' controls
whether to copy the expansion verbatim.
However, if the expansion contains a complex mixed case pattern, and
the abbrev matches this pattern as far as it goes, then the expansion is
always copied verbatim, regardless of those variables. Thus, for
example, if the buffer contains `variableWithSillyCasePattern', and you
type `v a M-/', it copies the expansion verbatim including its case
pattern.
The variable `dabbrev-abbrev-char-regexp', if non-`nil', controls
which characters are considered part of a word, for dynamic expansion
purposes. The regular expression must match just one character, never
two or more. The same regular expression also determines which
characters are part of an expansion. The value `nil' has a special
meaning: abbreviations are made of word characters, but expansions are
made of word and symbol characters.
In shell scripts and makefiles, a variable name is sometimes prefixed
with `$' and sometimes not. Major modes for this kind of text can
customize dynamic abbreviation to handle optional prefixes by setting
the variable `dabbrev-abbrev-skip-leading-regexp'. Its value should be
a regular expression that matches the optional prefix that dynamic
abbreviation should ignore.
Editing Pictures
****************
To edit a picture made out of text characters (for example, a picture
of the division of a register into fields, as a comment in a program),
use the command `M-x edit-picture' to enter Picture mode.
In Picture mode, editing is based on the "quarter-plane" model of
text, according to which the text characters lie studded on an area that
stretches infinitely far to the right and downward. The concept of the
end of a line does not exist in this model; the most you can say is
where the last nonblank character on the line is found.
Of course, Emacs really always considers text as a sequence of
characters, and lines really do have ends. But Picture mode replaces
the most frequently-used commands with variants that simulate the
quarter-plane model of text. They do this by inserting spaces or by
converting tabs to spaces.
Most of the basic editing commands of Emacs are redefined by Picture
mode to do essentially the same thing but in a quarter-plane way. In
addition, Picture mode defines various keys starting with the `C-c'
prefix to run special picture editing commands.
One of these keys, `C-c C-c', is pretty important. Often a picture
is part of a larger file that is usually edited in some other major
mode. `M-x edit-picture' records the name of the previous major mode
so you can use the `C-c C-c' command (`picture-mode-exit') later to go
back to that mode. `C-c C-c' also deletes spaces from the ends of
lines, unless given a numeric argument.
The special commands of Picture mode all work in other modes
(provided the `picture' library is loaded), but are not bound to keys
except in Picture mode. The descriptions below talk of moving "one
column" and so on, but all the picture mode commands handle numeric
arguments as their normal equivalents do.
Turning on Picture mode runs the hook `picture-mode-hook' (*note
Hooks::.).
Basic Editing in Picture Mode
=============================
Most keys do the same thing in Picture mode that they usually do, but
do it in a quarter-plane style. For example, `C-f' is rebound to run
`picture-forward-column', a command which moves point one column to the
right, inserting a space if necessary so that the actual end of the
line makes no difference. `C-b' is rebound to run
`picture-backward-column', which always moves point left one column,
converting a tab to multiple spaces if necessary. `C-n' and `C-p' are
rebound to run `picture-move-down' and `picture-move-up', which can
either insert spaces or convert tabs as necessary to make sure that
point stays in exactly the same column. `C-e' runs
`picture-end-of-line', which moves to after the last nonblank character
on the line. There is no need to change `C-a', as the choice of screen
model does not affect beginnings of lines.
Insertion of text is adapted to the quarter-plane screen model
through the use of Overwrite mode (*note Minor Modes::.).
Self-inserting characters replace existing text, column by column,
rather than pushing existing text to the right. <RET> runs
`picture-newline', which just moves to the beginning of the following
line so that new text will replace that line.
Picture mode provides erasure instead of deletion and killing of
text. <DEL> (`picture-backward-clear-column') replaces the preceding
character with a space rather than removing it; this moves point
backwards. `C-d' (`picture-clear-column') replaces the next character
or characters with spaces, but does not move point. (If you want to
clear characters to spaces and move forward over them, use <SPC>.)
`C-k' (`picture-clear-line') really kills the contents of lines, but
does not delete the newlines from the buffer.
To do actual insertion, you must use special commands. `C-o'
(`picture-open-line') creates a blank line after the current line; it
never splits a line. `C-M-o' (`split-line') makes sense in Picture
mode, so it is not changed. `C-j' (`picture-duplicate-line') inserts
below the current line another line with the same contents.
To do actual deletion in Picture mode, use `C-w', `C-c C-d' (which
is defined as `delete-char', as `C-d' is in other modes), or one of the
picture rectangle commands (*note Rectangles in Picture::.).
Controlling Motion after Insert
===============================
Since "self-inserting" characters in Picture mode overwrite and move
point, there is no essential restriction on how point should be moved.
Normally point moves right, but you can specify any of the eight
orthogonal or diagonal directions for motion after a "self-inserting"
character. This is useful for drawing lines in the buffer.
`C-c <'
Move left after insertion (`picture-movement-left').
`C-c >'
Move right after insertion (`picture-movement-right').
`C-c ^'
Move up after insertion (`picture-movement-up').
`C-c .'
Move down after insertion (`picture-movement-down').
`C-c `'
Move up and left ("northwest") after insertion
(`picture-movement-nw').
`C-c ''
Move up and right ("northeast") after insertion
(`picture-movement-ne').
`C-c /'
Move down and left ("southwest") after insertion
(`picture-movement-sw').
`C-c \'
Move down and right ("southeast") after insertion
(`picture-movement-se').
Two motion commands move based on the current Picture insertion
direction. The command `C-c C-f' (`picture-motion') moves in the same
direction as motion after "insertion" currently does, while `C-c C-b'
(`picture-motion-reverse') moves in the opposite direction.
Picture Mode Tabs
=================
Two kinds of tab-like action are provided in Picture mode. Use
`M-<TAB>' (`picture-tab-search') for context-based tabbing. With no
argument, it moves to a point underneath the next "interesting"
character that follows whitespace in the previous nonblank line.
"Next" here means "appearing at a horizontal position greater than the
one point starts out at." With an argument, as in `C-u M-<TAB>', this
command moves to the next such interesting character in the current
line. `M-<TAB>' does not change the text; it only moves point.
"Interesting" characters are defined by the variable
`picture-tab-chars', which should define a set of characters. The
syntax for this variable is like the syntax used inside of `[...]' in a
regular expression--but without the `[' and the `]'. Its default value
is `"!-~"'.
<TAB> itself runs `picture-tab', which operates based on the current
tab stop settings; it is the Picture mode equivalent of
`tab-to-tab-stop'. Normally it just moves point, but with a numeric
argument it clears the text that it moves over.
The context-based and tab-stop-based forms of tabbing are brought
together by the command `C-c <TAB>' (`picture-set-tab-stops'). This
command sets the tab stops to the positions which `M-<TAB>' would
consider significant in the current line. The use of this command,
together with <TAB>, can get the effect of context-based tabbing. But
`M-<TAB>' is more convenient in the cases where it is sufficient.
It may be convenient to prevent use of actual tab characters in
pictures. For example, this prevents `C-x <TAB>' from messing up the
picture. You can do this by setting the variable `indent-tabs-mode' to
`nil'. *Note Just Spaces::.
Picture Mode Rectangle Commands
===============================
Picture mode defines commands for working on rectangular pieces of
the text in ways that fit with the quarter-plane model. The standard
rectangle commands may also be useful (*note Rectangles::.).
`C-c C-k'
Clear out the region-rectangle with spaces
(`picture-clear-rectangle'). With argument, delete the text.
`C-c C-w R'
Similar but save rectangle contents in register R first
(`picture-clear-rectangle-to-register').
`C-c C-y'
Copy last killed rectangle into the buffer by overwriting, with
upper left corner at point (`picture-yank-rectangle'). With
argument, insert instead.
`C-c C-x R'
Similar, but use the rectangle in register R
(`picture-yank-rectangle-from-register').
The picture rectangle commands `C-c C-k' (`picture-clear-rectangle')
and `C-c C-w' (`picture-clear-rectangle-to-register') differ from the
standard rectangle commands in that they normally clear the rectangle
instead of deleting it; this is analogous with the way `C-d' is changed
in Picture mode.
However, deletion of rectangles can be useful in Picture mode, so
these commands delete the rectangle if given a numeric argument. `C-c
C-k' either with or without a numeric argument saves the rectangle for
`C-c C-y'.
The Picture mode commands for yanking rectangles differ from the
standard ones in overwriting instead of inserting. This is the same way
that Picture mode insertion of other text differs from other modes.
`C-c C-y' (`picture-yank-rectangle') inserts (by overwriting) the
rectangle that was most recently killed, while `C-c C-x'
(`picture-yank-rectangle-from-register') does likewise for the
rectangle found in a specified register.
Sending Mail
************
To send a message in Emacs, you start by typing a command (`C-x m')
to select and initialize the `*mail*' buffer. Then you edit the text
and headers of the message in this buffer, and type another command
(`C-c C-s' or `C-c C-c') to send the message.
`C-x m'
Begin composing a message to send (`compose-mail').
`C-x 4 m'
Likewise, but display the message in another window
(`compose-mail-other-window').
`C-x 5 m'
Likewise, but make a new frame (`compose-mail-other-frame').
`C-c C-s'
In Mail mode, send the message (`mail-send').
`C-c C-c'
Send the message and bury the mail buffer (`mail-send-and-exit').
The command `C-x m' (`compose-mail') selects a buffer named `*mail*'
and initializes it with the skeleton of an outgoing message. `C-x 4 m'
(`compose-mail-other-window') selects the `*mail*' buffer in a
different window, leaving the previous current buffer visible. `C-x 5
m' (`compose-mail-other-frame') creates a new frame to select the
`*mail*' buffer.
Because the mail-composition buffer is an ordinary Emacs buffer, you
can switch to other buffers while in the middle of composing mail, and
switch back later (or never). If you use the `C-x m' command again
when you have been composing another message but have not sent it, you
are asked to confirm before the old message is erased. If you answer
`n', the `*mail*' buffer is left selected with its old contents, so you
can finish the old message and send it. `C-u C-x m' is another way to
do this. Sending the message marks the `*mail*' buffer "unmodified,"
which avoids the need for confirmation when `C-x m' is next used.
If you are composing a message in the `*mail*' buffer and want to
send another message before finishing the first, rename the `*mail*'
buffer using `M-x rename-uniquely' (*note Misc Buffer::.). Then you
can use `C-x m' or its variants described above to make a new `*mail*'
buffer. Once you've done that, you can work with each mail buffer
independently.
The Format of the Mail Buffer
=============================
In addition to the "text" or "body", a message has "header fields"
which say who sent it, when, to whom, why, and so on. Some header
fields, such as `Date' and `Sender', are created automatically when you
send the message. Others, such as the recipient names, must be
specified by you in order to send the message properly.
Mail mode provides a few commands to help you edit some header
fields, and some are preinitialized in the buffer automatically at
times. You can insert and edit header fields using ordinary editing
commands.
The line in the buffer that says
--text follows this line--
is a special delimiter that separates the headers you have specified
from the text. Whatever follows this line is the text of the message;
the headers precede it. The delimiter line itself does not appear in
the message actually sent. The text used for the delimiter line is
controlled by the variable `mail-header-separator'.
Here is an example of what the headers and text in the mail buffer
might look like.
To: gnu@gnu.org
CC: lungfish@spam.org, byob@spam.org
Subject: The Emacs Manual
--Text follows this line--
Please ignore this message.
Mail Header Fields
==================
A header field in the mail buffer starts with a field name at the
beginning of a line, terminated by a colon. Upper and lower case are
equivalent in field names (and in mailing addresses also). After the
colon and optional whitespace comes the contents of the field.
You can use any name you like for a header field, but normally people
use only standard field names with accepted meanings. Here is a table
of fields commonly used in outgoing messages.
`To'
This field contains the mailing addresses to which the message is
addressed. If you list more than one address, use commas, not
spaces, to separate them.
`Subject'
The contents of the `Subject' field should be a piece of text that
says what the message is about. The reason `Subject' fields are
useful is that most mail-reading programs can provide a summary of
messages, listing the subject of each message but not its text.
`CC'
This field contains additional mailing addresses to send the
message to, like `To' except that these readers should not regard
the message as directed at them.
`BCC'
This field contains additional mailing addresses to send the
message to, which should not appear in the header of the message
actually sent. Copies sent this way are called "blind carbon
copies".
To send a blind carbon copy of every outgoing message to yourself,
set the variable `mail-self-blind' to `t'.
`FCC'
This field contains the name of one file and directs Emacs to
append a copy of the message to that file when you send the
message. If the file is in Rmail format, Emacs writes the message
in Rmail format; otherwise, Emacs writes the message in system
mail file format.
To put a fixed file name in the `FCC' field each time you start
editing an outgoing message, set the variable
`mail-archive-file-name' to that file name. Unless you remove the
`FCC' field before sending, the message will be written into that
file when it is sent.
`From'
Use the `From' field to say who you are, when the account you are
using to send the mail is not your own. The contents of the `From'
field should be a valid mailing address, since replies will
normally go there. If you don't specify the `From' field
yourself, Emacs uses the value of `user-mail-address' as the
default.
`Reply-to'
Use this field to direct replies to a different address. Most
mail-reading programs (including Rmail) automatically send replies
to the `Reply-to' address in preference to the `From' address. By
adding a `Reply-to' field to your header, you can work around any
problems your `From' address may cause for replies.
To put a fixed `Reply-to' address into every outgoing message, set
the variable `mail-default-reply-to' to that address (as a string).
Then `mail' initializes the message with a `Reply-to' field as
specified. You can delete or alter that header field before you
send the message, if you wish. When Emacs starts up, if the
environment variable `REPLYTO' is set, `mail-default-reply-to' is
initialized from that environment variable.
`In-reply-to'
This field contains a piece of text describing a message you are
replying to. Some mail systems can use this information to
correlate related pieces of mail. Normally this field is filled
in by Rmail when you reply to a message in Rmail, and you never
need to think about it (*note Rmail::.).
`References'
This field lists the message IDs of related previous messages.
Rmail sets up this field automatically when you reply to a message.
The `To', `CC', `BCC' and `FCC' header fields can appear any number
of times, and each such header field can contain multiple addresses,
separated by commas. This way, you can specify any number of places to
send the message. A `To', `CC', or `BCC' field can also have
continuation lines: one or more lines starting with whitespace,
following the starting line of the field, are considered part of the
field. Here's an example of a `To' field with a continuation line:
To: foo@here.net, this@there.net,
me@gnu.cambridge.mass.usa.earth.spiral3281
When you send the message, if you didn't write a `From' field
yourself, Emacs puts in one for you. The variable `mail-from-style'
controls the format:
`nil'
Use just the email address, as in `king@grassland.com'.
`parens'
Use both email address and full name, as in `king@grassland.com
(Elvis Parsley)'.
`angles'
Use both email address and full name, as in `Elvis Parsley
<king@grassland.com>'.
`system-default'
Allow the system to insert the `From' field.
Mail Aliases
============
You can define "mail aliases" in a file named `~/.mailrc'. These
are short mnemonic names which stand for mail addresses or groups of
mail addresses. Like many other mail programs, Emacs expands aliases
when they occur in the `To', `From', `CC', `BCC', and `Reply-to'
fields, plus their `Resent-' variants.
To define an alias in `~/.mailrc', write a line in the following
format:
alias SHORTADDRESS FULLADDRESSES
Here FULLADDRESSES stands for one or more mail addresses for
SHORTADDRESS to expand into. Separate multiple addresses with spaces;
if an address contains a space, quote the whole address with a pair of
double-quotes.
For instance, to make `maingnu' stand for `gnu@gnu.org' plus a local
address of your own, put in this line:
alias maingnu gnu@gnu.org local-gnu
Emacs also recognizes include commands in `.mailrc' files. They
look like this:
source FILENAME
The file `~/.mailrc' is used primarily by other mail-reading programs;
it can contain various other commands. Emacs ignores everything in it
except for alias definitions and include commands.
Another way to define a mail alias, within Emacs alone, is with the
`define-mail-alias' command. It prompts for the alias and then the
full address. You can use it to define aliases in your `.emacs' file,
like this:
(define-mail-alias "maingnu" "gnu@gnu.org")
`define-mail-alias' records aliases by adding them to a variable
named `mail-aliases'. If you are comfortable with manipulating Lisp
lists, you can set `mail-aliases' directly. The initial value of
`mail-aliases' is `t', which means that Emacs should read `.mailrc' to
get the proper value.
You can specify a different file name to use instead of `~/.mailrc'
by setting the variable `mail-personal-alias-file'.
Normally, Emacs expands aliases when you send the message. You do
not need to expand mail aliases before sending the message, but you can
expand them if you want to see where the mail will actually go. To do
this, use the command `M-x expand-mail-aliases'; it expands all mail
aliases currently present in the mail headers that hold addresses.
If you like, you can have mail aliases expand as abbrevs, as soon as
you type them in (*note Abbrevs::.). To enable this feature, execute
the following:
(add-hook 'mail-setup-hook 'mail-abbrevs-setup)
This can go in your `.emacs' file. *Note Hooks::. If you use this
feature, you must use `define-mail-abbrev' instead of
`define-mail-alias'; the latter does not work with this package. Note
that the mail abbreviation package uses the variable `mail-abbrevs'
instead of `mail-aliases', and that all alias names are converted to
lower case.
The mail abbreviation package also provides the `C-c C-a'
(`mail-interactive-insert-alias') command, which reads an alias name
(with completion) and inserts its definition at point. This is useful
when editing the message text itself or a header field such as
`Subject' in which Emacs does not normally expand aliases.
Note that abbrevs expand only if you insert a word-separator
character afterward. However, you can rebind `C-n' and `M->' to cause
expansion as well. Here's how to do that:
(add-hook 'mail-setup-hook
'(lambda ()
(substitute-key-definition
'next-line 'mail-abbrev-next-line
mail-mode-map global-map)
(substitute-key-definition
'end-of-buffer 'mail-abbrev-end-of-buffer
mail-mode-map global-map)))
Mail Mode
=========
The major mode used in the mail buffer is Mail mode, which is much
like Text mode except that various special commands are provided on the
`C-c' prefix. These commands all have to do specifically with editing
or sending the message. In addition, Mail mode defines the character
`%' as a word separator; this is helpful for using the word commands to
edit mail addresses.
Mail mode is normally used in buffers set up automatically by the
`mail' command and related commands. However, you can also switch to
Mail mode in a file-visiting buffer. That is a useful thing to do if
you have saved draft message text in a file.
Mail Sending
------------
Mail mode has two commands for sending the message you have been
editing:
`C-c C-s'
Send the message, and leave the mail buffer selected (`mail-send').
`C-c C-c'
Send the message, and select some other buffer
(`mail-send-and-exit').
`C-c C-s' (`mail-send') sends the message and marks the mail buffer
unmodified, but leaves that buffer selected so that you can modify the
message (perhaps with new recipients) and send it again. `C-c C-c'
(`mail-send-and-exit') sends and then deletes the window or switches to
another buffer. It puts the mail buffer at the lowest priority for
reselection by default, since you are finished with using it. This is
the usual way to send the message.
In a file-visiting buffer, sending the message does not clear the
modified flag, because only saving the file should do that. As a
result, you don't get a warning if you try to send the same message
twice.
When you send a message that contains non-ASCII characters, they need
to be encoded with a coding system (*note Coding Systems::.). Usually
the coding system is specified automatically by your chosen language
environment (*note Language Environments::.). You can explicitly
specify the coding system for outgoing mail by setting the variable
`sendmail-coding-system'.
If the coding system thus determined does not handle the characters
in a particular message, Emacs asks you to select the coding system to
use, showing a list of possible coding systems.
Mail Header Editing
-------------------
Mail mode provides special commands to move to particular header
fields and to complete addresses in headers.
`C-c C-f C-t'
Move to the `To' header field, creating one if there is none
(`mail-to').
`C-c C-f C-s'
Move to the `Subject' header field, creating one if there is none
(`mail-subject').
`C-c C-f C-c'
Move to the `CC' header field, creating one if there is none
(`mail-cc').
`C-c C-f C-b'
Move to the `BCC' header field, creating one if there is none
(`mail-bcc').
`C-c C-f C-f'
Move to the `FCC' header field, creating one if there is none
(`mail-fcc').
`M-<TAB>'
Complete a mailing address (`mail-complete').
There are five commands to move point to particular header fields,
all based on the prefix `C-c C-f' (`C-f' is for "field"). They are
listed in the table above. If the field in question does not exist,
these commands create one. We provide special motion commands for these
particular fields because they are the fields users most often want to
edit.
While editing a header field that contains mailing addresses, such as
`To:', `CC:' and `BCC:', you can complete a mailing address by typing
`M-<TAB>' (`mail-complete'). It inserts the full name corresponding to
the address, if it can determine the full name. The variable
`mail-complete-style' controls whether to insert the full name, and
what style to use, as in `mail-from-style' (*note Mail Headers::.).
For completion purposes, the valid mailing addresses are taken to be
the local users' names plus your personal mail aliases. You can specify
additional sources of valid addresses; use the customization buffer to
see the options for this.
If you type `M-<TAB>' in the body of the message, it invokes
`ispell-complete-word', as in Text mode.
Citing Mail
-----------
Mail mode also has commands for yanking or "citing" all or part of a
message that you are replying to. These commands are active only when
you started sending a message using an Rmail command.
`C-c C-y'
Yank the selected message from Rmail (`mail-yank-original').
`C-c C-r'
Yank the region from the Rmail buffer (`mail-yank-region').
`C-c C-q'
Fill each paragraph cited from another message
(`mail-fill-yanked-message').
When mail sending is invoked from the Rmail mail reader using an
Rmail command, `C-c C-y' can be used inside the mail buffer to insert
the text of the message you are replying to. Normally it indents each
line of that message three spaces and eliminates most header fields. A
numeric argument specifies the number of spaces to indent. An argument
of just `C-u' says not to indent at all and not to eliminate anything.
`C-c C-y' always uses the current message from the Rmail buffer, so you
can insert several old messages by selecting one in Rmail, switching to
`*mail*' and yanking it, then switching back to Rmail to select another.
You can specify the text for `C-c C-y' to insert at the beginning of
each line: set `mail-yank-prefix' to the desired string. (A value of
`nil' means to use indentation; this is the default.) However, `C-u
C-c C-y' never adds anything at the beginning of the inserted lines,
regardless of the value of `mail-yank-prefix'.
To yank just a part of an incoming message, set the region in Rmail
to the part you want; then go to the `*Mail*' message and type `C-c
C-r' (`mail-yank-region'). Each line that is copied is indented or
prefixed according to `mail-yank-prefix'.
After using `C-c C-y' or `C-c C-r', you can type `C-c C-q'
(`mail-fill-yanked-message') to fill the paragraphs of the yanked old
message or messages. One use of `C-c C-q' fills all such paragraphs,
each one individually. To fill a single paragraph of the quoted
message, use `M-q'. If filling does not automatically handle the type
of citation prefix you use, try setting the fill prefix explicitly.
*Note Filling::.
Mail Mode Miscellany
--------------------
`C-c C-t'
Move to the beginning of the message body text (`mail-text').
`C-c C-w'
Insert the file `~/.signature' at the end of the message text
(`mail-signature').
`C-c C-i FILE <RET>'
Insert the contents of FILE at the end of the outgoing message
(`mail-attach-file').
`M-x ispell-message'
Do spelling correction on the message text, but not on citations
from other messages.
`C-c C-t' (`mail-text') moves point to just after the header
separator line--that is, to the beginning of the message body text.
`C-c C-w' (`mail-signature') adds a standard piece of text at the
end of the message to say more about who you are. The text comes from
the file `~/.signature' in your home directory. To insert your
signature automatically, set the variable `mail-signature' to `t'; then
starting a mail message automatically inserts the contents of your
`~/.signature' file. If you want to omit your signature from a
particular message, delete it from the buffer before you send the
message.
You can also set `mail-signature' to a string; then that string is
inserted automatically as your signature when you start editing a
message to send. If you set it to some other Lisp expression, the
expression is evaluated each time, and its value (which should be a
string) specifies the signature.
You can do spelling correction on the message text you have written
with the command `M-x ispell-message'. If you have yanked an incoming
message into the outgoing draft, this command skips what was yanked,
but it checks the text that you yourself inserted. (It looks for
indentation or `mail-yank-prefix' to distinguish the cited lines from
your input.) *Note Spelling::.
To include a file in the outgoing message, you can use `C-x i', the
usual command to insert a file in the current buffer. But it is often
more convenient to use a special command, `C-c C-i'
(`mail-attach-file'). This command inserts the file contents at the
end of the buffer, after your signature if any, with a delimiter line
that includes the file name.
Turning on Mail mode (which `C-x m' does automatically) runs the
normal hooks `text-mode-hook' and `mail-mode-hook'. Initializing a new
outgoing message runs the normal hook `mail-setup-hook'; if you want to
add special fields to your mail header or make other changes to the
appearance of the mail buffer, use that hook. *Note Hooks::.
The main difference between these hooks is just when they are
invoked. Whenever you type `M-x mail', `mail-mode-hook' runs as soon
as the `*mail*' buffer is created. Then the `mail-setup' function puts
in the default contents of the buffer. After these default contents
are inserted, `mail-setup-hook' runs.
Distracting the NSA
===================
`M-x spook' adds a line of randomly chosen keywords to an outgoing
mail message. The keywords are chosen from a list of words that suggest
you are discussing something subversive.
The idea behind this feature is the suspicion that the NSA snoops on
all electronic mail messages that contain keywords suggesting they might
find them interesting. (The NSA says they don't, but that's what they
*would* say.) The idea is that if lots of people add suspicious words
to their messages, the NSA will get so busy with spurious input that
they will have to give up reading it all.
Here's how to insert spook keywords automatically whenever you start
entering an outgoing message:
(add-hook 'mail-setup-hook 'spook)
Whether or not this confuses the NSA, it at least amuses people.
Mail-Composition Methods
========================
This chapter describes the usual Emacs mode for editing and sending
mail--Mail mode. Emacs has alternative facilities for editing and
sending mail, including MH-E and Message mode, not documented in this
manual. You can choose any of them as your preferred method. The
commands `C-x m', `C-x 4 m' and `C-x 5 m' use whichever agent you have
specified. So do various other Emacs commands and facilities that send
mail.
To specify your mail-composition method, set the variable
`mail-user-agent'. Currently legitimate values include
`sendmail-user-agent', `mh-e-user-agent', and `message-user-agent'.
If you select a different mail-composition method, the information in
this chapter about the `*mail*' buffer and Mail mode does not apply;
other methods may use completely different commands with a different
format in a differently named buffer.
Reading Mail with Rmail
***********************
Rmail is an Emacs subsystem for reading and disposing of mail that
you receive. Rmail stores mail messages in files called Rmail files.
Reading the message in an Rmail file is done in a special major mode,
Rmail mode, which redefines most letters to run commands for managing
mail. The command `rmail-mode' is used to switch into Rmail mode, and
it runs the hook `rmail-mode-hook' as usual, but don't run this command
by hand; it can't do a reasonable job unless the buffer is visiting a
proper Rmail file.
Basic Concepts of Rmail
=======================
Using Rmail in the simplest fashion, you have one Rmail file
`~/RMAIL' in which all of your mail is saved. It is called your
"primary Rmail file". The command `M-x rmail' reads your primary Rmail
file, merges new mail in from your inboxes, displays the first message
you haven't read yet, and lets you begin reading. The variable
`rmail-file-name' specifies the name of the primary Rmail file.
Rmail uses narrowing to hide all but one message in the Rmail file.
The message that is shown is called the "current message". Rmail
mode's special commands can do such things as delete the current
message, copy it into another file, send a reply, or move to another
message. You can also create multiple Rmail files and use Rmail to move
messages between them.
Within the Rmail file, messages are normally arranged sequentially in
order of receipt; you can specify other ways to sort them. Messages are
assigned consecutive integers as their "message numbers". The number
of the current message is displayed in Rmail's mode line, followed by
the total number of messages in the file. You can move to a message by
specifying its message number with the `j' key (*note Rmail Motion::.).
Following the usual conventions of Emacs, changes in an Rmail file
become permanent only when the file is saved. You can save it with `s'
(`rmail-save'), which also expunges deleted messages from the file
first (*note Rmail Deletion::.). To save the file without expunging,
use `C-x C-s'. Rmail also saves the Rmail file after merging new mail
from an inbox file (*note Rmail Inbox::.).
You can exit Rmail with `q' (`rmail-quit'); this expunges and saves
the Rmail file and then switches to another buffer. But there is no
need to `exit' formally. If you switch from Rmail to editing in other
buffers, and never happen to switch back, you have exited. (The Rmail
command `b', `rmail-bury', does this for you.) Just make sure to save
the Rmail file eventually (like any other file you have changed). `C-x
s' is a good enough way to do this (*note Saving::.).
Scrolling Within a Message
==========================
When Rmail displays a message that does not fit on the screen, you
must scroll through it to read the rest. You could do this with `C-v',
`M-v' and `M-<', but in Rmail scrolling is so frequent that it deserves
to be easier to type.
`<SPC>'
Scroll forward (`scroll-up').
`<DEL>'
Scroll backward (`scroll-down').
`.'
Scroll to start of message (`rmail-beginning-of-message').
Since the most common thing to do while reading a message is to
scroll through it by screenfuls, Rmail makes <SPC> and <DEL> synonyms of
`C-v' (`scroll-up') and `M-v' (`scroll-down')
The command `.' (`rmail-beginning-of-message') scrolls back to the
beginning of the selected message. This is not quite the same as `M-<':
for one thing, it does not set the mark; for another, it resets the
buffer boundaries to the current message if you have changed them.
Moving Among Messages
=====================
The most basic thing to do with a message is to read it. The way to
do this in Rmail is to make the message current. The usual practice is
to move sequentially through the file, since this is the order of
receipt of messages. When you enter Rmail, you are positioned at the
first message that you have not yet made current (that is, the first one
that has the `unseen' attribute; *note Rmail Attributes::.). Move
forward to see the other new messages; move backward to reexamine old
messages.
`n'
Move to the next nondeleted message, skipping any intervening
deleted messages (`rmail-next-undeleted-message').
`p'
Move to the previous nondeleted message
(`rmail-previous-undeleted-message').
`M-n'
Move to the next message, including deleted messages
(`rmail-next-message').
`M-p'
Move to the previous message, including deleted messages
(`rmail-previous-message').
`j'
Move to the first message. With argument N, move to message
number N (`rmail-show-message').
`>'
Move to the last message (`rmail-last-message').
`<'
Move to the first message (`rmail-first-message').
`M-s REGEXP <RET>'
Move to the next message containing a match for REGEXP
(`rmail-search').
`- M-s REGEXP <RET>'
Move to the previous message containing a match for REGEXP.
`n' and `p' are the usual way of moving among messages in Rmail.
They move through the messages sequentially, but skip over deleted
messages, which is usually what you want to do. Their command
definitions are named `rmail-next-undeleted-message' and
`rmail-previous-undeleted-message'. If you do not want to skip deleted
messages--for example, if you want to move to a message to undelete
it--use the variants `M-n' and `M-p' (`rmail-next-message' and
`rmail-previous-message'). A numeric argument to any of these commands
serves as a repeat count.
In Rmail, you can specify a numeric argument by typing just the
digits. You don't need to type `C-u' first.
The `M-s' (`rmail-search') command is Rmail's version of search.
The usual incremental search command `C-s' works in Rmail, but it
searches only within the current message. The purpose of `M-s' is to
search for another message. It reads a regular expression (*note
Regexps::.) nonincrementally, then searches starting at the beginning
of the following message for a match. It then selects that message.
If REGEXP is empty, `M-s' reuses the regexp used the previous time.
To search backward in the file for another message, give `M-s' a
negative argument. In Rmail you can do this with `- M-s'.
It is also possible to search for a message based on labels. *Note
Rmail Labels::.
To move to a message specified by absolute message number, use `j'
(`rmail-show-message') with the message number as argument. With no
argument, `j' selects the first message. `<' (`rmail-first-message')
also selects the first message. `>' (`rmail-last-message') selects the
last message.
Deleting Messages
=================
When you no longer need to keep a message, you can "delete" it. This
flags it as ignorable, and some Rmail commands pretend it is no longer
present; but it still has its place in the Rmail file, and still has its
message number.
"Expunging" the Rmail file actually removes the deleted messages.
The remaining messages are renumbered consecutively. Expunging is the
only action that changes the message number of any message, except for
undigestifying (*note Rmail Digest::.).
`d'
Delete the current message, and move to the next nondeleted message
(`rmail-delete-forward').
`C-d'
Delete the current message, and move to the previous nondeleted
message (`rmail-delete-backward').
`u'
Undelete the current message, or move back to a deleted message and
undelete it (`rmail-undelete-previous-message').
`x'
Expunge the Rmail file (`rmail-expunge').
There are two Rmail commands for deleting messages. Both delete the
current message and select another message. `d'
(`rmail-delete-forward') moves to the following message, skipping
messages already deleted, while `C-d' (`rmail-delete-backward') moves
to the previous nondeleted message. If there is no nondeleted message
to move to in the specified direction, the message that was just
deleted remains current. A numeric argument to either command reverses
the direction of motion after deletion.
Whenever Rmail deletes a message, it invokes the function(s) listed
in `rmail-delete-message-hook'. When the hook functions are invoked,
the message has been marked deleted, but it is still the current message
in the Rmail buffer.
To make all the deleted messages finally vanish from the Rmail file,
type `x' (`rmail-expunge'). Until you do this, you can still
"undelete" the deleted messages. The undeletion command, `u'
(`rmail-undelete-previous-message'), is designed to cancel the effect
of a `d' command in most cases. It undeletes the current message if
the current message is deleted. Otherwise it moves backward to
previous messages until a deleted message is found, and undeletes that
message.
You can usually undo a `d' with a `u' because the `u' moves back to
and undeletes the message that the `d' deleted. But this does not work
when the `d' skips a few already-deleted messages that follow the
message being deleted; then the `u' command undeletes the last of the
messages that were skipped. There is no clean way to avoid this
problem. However, by repeating the `u' command, you can eventually get
back to the message that you intend to undelete. You can also select a
particular deleted message with the `M-p' command, then type `u' to
undelete it.
A deleted message has the `deleted' attribute, and as a result
`deleted' appears in the mode line when the current message is deleted.
In fact, deleting or undeleting a message is nothing more than adding
or removing this attribute. *Note Rmail Attributes::.
Rmail Files and Inboxes
=======================
The operating system places incoming mail for you in a file that we
call your "inbox". When you start up Rmail, it runs a C program called
`movemail' to copy the new messages from your inbox into your primary
Rmail file, which also contains other messages saved from previous
Rmail sessions. It is in this file that you actually read the mail
with Rmail. This operation is called "getting new mail". You can get
new mail at any time in Rmail by typing `g'.
The variable `rmail-primary-inbox-list' contains a list of the files
which are inboxes for your primary Rmail file. If you don't set this
variable explicitly, it is initialized from the `MAIL' environment
variable, or, as a last resort, set to `nil', which means to use the
default inbox. The default inbox is `/var/mail/USERNAME',
`/usr/spool/mail/USERNAME', or `/usr/mail/USERNAME', depending on your
operating system.
To see what the default is on your system, use `C-h v
rmail-primary-inbox <RET>'. You can specify the inbox file(s) for any
Rmail file with the command `set-rmail-inbox-list'; see *Note Rmail
Files::.
There are two reasons for having separate Rmail files and inboxes.
1. The inbox file format varies between operating systems and
according to the other mail software in use. Only one part of
Rmail needs to know about the alternatives, and it need only
understand how to convert all of them to Rmail's own format.
2. It is very cumbersome to access an inbox file without danger of
losing mail, because it is necessary to interlock with mail
delivery. Moreover, different operating systems use different
interlocking techniques. The strategy of moving mail out of the
inbox once and for all into a separate Rmail file avoids the need
for interlocking in all the rest of Rmail, since only Rmail
operates on the Rmail file.
Rmail was written to use Babyl format as its internal format. Since
then, we have recognized that the usual inbox format on Unix and GNU
systems is adequate for the job, and we plan to change Rmail to use that
as its internal format. However, the Rmail file will still be separate
from the inbox file, even on systems where their format is the same.
Multiple Rmail Files
====================
Rmail operates by default on your "primary Rmail file", which is
named `~/RMAIL' and receives your incoming mail from your system inbox
file. But you can also have other Rmail files and edit them with
Rmail. These files can receive mail through their own inboxes, or you
can move messages into them with explicit Rmail commands (*note Rmail
Output::.).
`i FILE <RET>'
Read FILE into Emacs and run Rmail on it (`rmail-input').
`M-x set-rmail-inbox-list <RET> FILES <RET>'
Specify inbox file names for current Rmail file to get mail from.
`g'
Merge new mail from current Rmail file's inboxes
(`rmail-get-new-mail').
`C-u g FILE <RET>'
Merge new mail from inbox file FILE.
To run Rmail on a file other than your primary Rmail file, you may
use the `i' (`rmail-input') command in Rmail. This visits the file in
Rmail mode. You can use `M-x rmail-input' even when not in Rmail.
The file you read with `i' should normally be a valid Rmail file.
If it is not, Rmail tries to decompose it into a stream of messages in
various known formats. If it succeeds, it converts the whole file to an
Rmail file. If you specify a file name that doesn't exist, `i'
initializes a new buffer for creating a new Rmail file.
You can also select an Rmail file from a menu. Choose first the menu
bar Classify item, then from the Classify menu choose the Input Rmail
File item; then choose the Rmail file you want. The variables
`rmail-secondary-file-directory' and `rmail-secondary-file-regexp'
specify which files to offer in the menu: the first variable says which
directory to find them in; the second says which files in that
directory to offer (all those that match the regular expression).
These variables also apply to choosing a file for output (*note Rmail
Output::.).
Each Rmail file can contain a list of inbox file names; you can
specify this list with `M-x set-rmail-inbox-list <RET> FILES <RET>'.
The argument can contain any number of file names, separated by commas.
It can also be empty, which specifies that this file should have no
inboxes. Once a list of inboxes is specified, the Rmail file remembers
it permanently until you specify a different list.
As a special exception, if your primary Rmail file does not specify
any inbox files, it uses your standard system inbox.
The `g' command (`rmail-get-new-mail') merges mail into the current
Rmail file from its specified inboxes. If the Rmail file has no
inboxes, `g' does nothing. The command `M-x rmail' also merges new
mail into your primary Rmail file.
To merge mail from a file that is not the usual inbox, give the `g'
key a numeric argument, as in `C-u g'. Then it reads a file name and
merges mail from that file. The inbox file is not deleted or changed
in any way when `g' with an argument is used. This is, therefore, a
general way of merging one file of messages into another.
Copying Messages Out to Files
=============================
These commands copy messages from an Rmail file into another file.
`o FILE <RET>'
Append a copy of the current message to the file FILE, using Rmail
file format by default (`rmail-output-to-rmail-file').
`C-o FILE <RET>'
Append a copy of the current message to the file FILE, using
system inbox file format by default (`rmail-output').
`w FILE <RET>'
Output just the message body to the file FILE, taking the default
file name from the message `Subject' header.
The commands `o' and `C-o' copy the current message into a specified
file. This file may be an Rmail file or it may be in system inbox
format; the output commands ascertain the file's format and write the
copied message in that format.
When copying a message to a file in Unix mail file format, these
commands include whichever header fields are currently visible. Use the
`t' command first, if you wish, to specify which headers to show (and
copy).
The `o' and `C-o' commands differ in two ways: each has its own
separate default file name, and each specifies a choice of format to
use when the file does not already exist. The `o' command uses Rmail
format when it creates a new file, while `C-o' uses system inbox format
for a new file. The default file name for `o' is the file name used
last with `o', and the default file name for `C-o' is the file name
used last with `C-o'.
If the output file is an Rmail file currently visited in an Emacs
buffer, the output commands copy the message into that buffer. It is
up to you to save the buffer eventually in its file.
Sometimes you may receive a message whose body holds the contents of
a file. You can save the body to a file (excluding the message header)
with the `w' command (`rmail-output-body-to-file'). Often these
messages contain the intended file name in the `Subject' field, so the
`w' command uses the `Subject' field as the default for the output file
name. However, the file name is read using the minibuffer, so you can
specify a different name if you wish.
You can also output a message to an Rmail file chosen with a menu.
Choose first the menu bar Classify item, then from the Classify menu
choose the Output Rmail File menu item; then choose the Rmail file you
want. This outputs the current message to that file, like the `o'
command. The variables `rmail-secondary-file-directory' and
`rmail-secondary-file-regexp' specify which files to offer in the menu:
the first variable says which directory to find them in; the second
says which files in that directory to offer (all those that match the
regular expression).
Copying a message gives the original copy of the message the `filed'
attribute, so that `filed' appears in the mode line when such a message
is current. If you like to keep just a single copy of every mail
message, set the variable `rmail-delete-after-output' to `t'; then the
`o' and `C-o' commands delete the original message after copying it.
(You can undelete the original afterward if you wish.)
Copying messages into files in system inbox format uses the header
fields that are displayed in Rmail at the time. Thus, if you use the
`t' command to view the entire header and then copy the message, the
entire header is copied. *Note Rmail Display::.
The variable `rmail-output-file-alist' lets you specify intelligent
defaults for the output file, based on the contents of the current
message. The value should be a list whose elements have this form:
(REGEXP . NAME-EXP)
If there's a match for REGEXP in the current message, then the default
file name for output is NAME-EXP. If multiple elements match the
message, the first matching element decides the default file name. The
subexpression NAME-EXP may be a string constant giving the file name to
use, or more generally it may be any Lisp expression that returns a
file name as a string. `rmail-output-file-alist' applies to both `o'
and `C-o'.
Labels
======
Each message can have various "labels" assigned to it as a means of
classification. Each label has a name; different names are different
labels. Any given label is either present or absent on a particular
message. A few label names have standard meanings and are given to
messages automatically by Rmail when appropriate; these special labels
are called "attributes". (*Note Rmail Attributes::.) All other labels
are assigned only by users.
`a LABEL <RET>'
Assign the label LABEL to the current message (`rmail-add-label').
`k LABEL <RET>'
Remove the label LABEL from the current message
(`rmail-kill-label').
`C-M-n LABELS <RET>'
Move to the next message that has one of the labels LABELS
(`rmail-next-labeled-message').
`C-M-p LABELS <RET>'
Move to the previous message that has one of the labels LABELS
(`rmail-previous-labeled-message').
`C-M-l LABELS <RET>'
Make a summary of all messages containing any of the labels LABELS
(`rmail-summary-by-labels').
The `a' (`rmail-add-label') and `k' (`rmail-kill-label') commands
allow you to assign or remove any label on the current message. If the
LABEL argument is empty, it means to assign or remove the same label
most recently assigned or removed.
Once you have given messages labels to classify them as you wish,
there are two ways to use the labels: in moving and in summaries.
The command `C-M-n LABELS <RET>' (`rmail-next-labeled-message')
moves to the next message that has one of the labels LABELS. The
argument LABELS specifies one or more label names, separated by commas.
`C-M-p' (`rmail-previous-labeled-message') is similar, but moves
backwards to previous messages. A numeric argument to either command
serves as a repeat count.
The command `C-M-l LABELS <RET>' (`rmail-summary-by-labels')
displays a summary containing only the messages that have at least one
of a specified set of labels. The argument LABELS is one or more label
names, separated by commas. *Note Rmail Summary::, for information on
summaries.
If the LABELS argument to `C-M-n', `C-M-p' or `C-M-l' is empty, it
means to use the last set of labels specified for any of these commands.
Rmail Attributes
================
Some labels such as `deleted' and `filed' have built-in meanings and
are assigned to or removed from messages automatically at appropriate
times; these labels are called "attributes". Here is a list of Rmail
attributes:
`unseen'
Means the message has never been current. Assigned to messages
when they come from an inbox file, and removed when a message is
made current. When you start Rmail, it initially shows the first
message that has this attribute.
`deleted'
Means the message is deleted. Assigned by deletion commands and
removed by undeletion commands (*note Rmail Deletion::.).
`filed'
Means the message has been copied to some other file. Assigned by
the file output commands (*note Rmail Files::.).
`answered'
Means you have mailed an answer to the message. Assigned by the
`r' command (`rmail-reply'). *Note Rmail Reply::.
`forwarded'
Means you have forwarded the message. Assigned by the `f' command
(`rmail-forward'). *Note Rmail Reply::.
`edited'
Means you have edited the text of the message within Rmail. *Note
Rmail Editing::.
`resent'
Means you have resent the message. Assigned by the command `M-x
rmail-resend'. *Note Rmail Reply::.
All other labels are assigned or removed only by the user, and have
no standard meaning.
Sending Replies
===============
Rmail has several commands that use Mail mode to send outgoing mail.
*Note Sending Mail::, for information on using Mail mode, including
certain features meant to work with Rmail. What this section documents
are the special commands of Rmail for entering Mail mode. Note that the
usual keys for sending mail--`C-x m', `C-x 4 m', and `C-x 5 m'--are
available in Rmail mode and work just as they usually do.
`m'
Send a message (`rmail-mail').
`c'
Continue editing the already started outgoing message
(`rmail-continue').
`r'
Send a reply to the current Rmail message (`rmail-reply').
`f'
Forward the current message to other users (`rmail-forward').
`C-u f'
Resend the current message to other users (`rmail-resend').
`M-m'
Try sending a bounced message a second time
(`rmail-retry-failure').
The most common reason to send a message while in Rmail is to reply
to the message you are reading. To do this, type `r' (`rmail-reply').
This displays the `*mail*' buffer in another window, much like `C-x 4
m', but preinitializes the `Subject', `To', `CC' and `In-reply-to'
header fields based on the message you are replying to. The `To' field
starts out as the address of the person who sent the message you
received, and the `CC' field starts out with all the other recipients
of that message.
You can exclude certain recipients from being placed automatically in
the `CC', using the variable `rmail-dont-reply-to-names'. Its value
should be a regular expression (as a string); any recipient that the
regular expression matches, is excluded from the `CC' field. The
default value matches your own name, and any name starting with
`info-'. (Those names are excluded because there is a convention of
using them for large mailing lists to broadcast announcements.)
To omit the `CC' field completely for a particular reply, enter the
reply command with a numeric argument: `C-u r' or `1 r'.
Once the `*mail*' buffer has been initialized, editing and sending
the mail goes as usual (*note Sending Mail::.). You can edit the
presupplied header fields if they are not right for you. You can also
use the commands of Mail mode (*note Mail Mode::.), including `C-c C-y'
which yanks in the message that you are replying to. You can switch to
the Rmail buffer, select a different message there, switch back, and
yank the new current message.
Sometimes a message does not reach its destination. Mailers usually
send the failed message back to you, enclosed in a "failure message".
The Rmail command `M-m' (`rmail-retry-failure') prepares to send the
same message a second time: it sets up a `*mail*' buffer with the same
text and header fields as before. If you type `C-c C-c' right away,
you send the message again exactly the same as the first time.
Alternatively, you can edit the text or headers and then send it. The
variable `rmail-retry-ignored-headers', in the same format as
`rmail-ignored-headers' (*note Rmail Display::.), controls which
headers are stripped from the failed message when retrying it; it
defaults to `nil'.
Another frequent reason to send mail in Rmail is to "forward" the
current message to other users. `f' (`rmail-forward') makes this easy
by preinitializing the `*mail*' buffer with the current message as the
text, and a subject designating a forwarded message. All you have to
do is fill in the recipients and send. When you forward a message,
recipients get a message which is "from" you, and which has the
original message in its contents.
Forwarding a message encloses it between two delimiter lines. It
also modifies every line that starts with a dash, by inserting `- ' at
the start of the line. When you receive a forwarded message, if it
contains something besides ordinary text--for example, program source
code--you might find it useful to undo that transformation. You can do
this by selecting the forwarded message and typing `M-x
unforward-rmail-message'. This command extracts the original forwarded
message, deleting the inserted `- ' strings, and inserts it into the
Rmail file as a separate message immediately following the current one.
"Resending" is an alternative similar to forwarding; the difference
is that resending sends a message that is "from" the original sender,
just as it reached you--with a few added header fields `Resent-from'
and `Resent-to' to indicate that it came via you. To resend a message
in Rmail, use `C-u f'. (`f' runs `rmail-forward', which is programmed
to invoke `rmail-resend' if you provide a numeric argument.)
The `m' (`rmail-mail') command is used to start editing an outgoing
message that is not a reply. It leaves the header fields empty. Its
only difference from `C-x 4 m' is that it makes the Rmail buffer
accessible for `C-c C-y', just as `r' does. Thus, `m' can be used to
reply to or forward a message; it can do anything `r' or `f' can do.
The `c' (`rmail-continue') command resumes editing the `*mail*'
buffer, to finish editing an outgoing message you were already
composing, or to alter a message you have sent.
If you set the variable `rmail-mail-new-frame' to a non-`nil' value,
then all the Rmail commands to start sending a message create a new
frame to edit it in. This frame is deleted when you send the message,
or when you use the `Don't Send' item in the `Mail' menu.
All the Rmail commands to send a message use the mail-composition
method that you have chosen (*note Mail Methods::.).
Summaries
=========
A "summary" is a buffer containing one line per message to give you
an overview of the mail in an Rmail file. Each line shows the message
number, the sender, the labels, and the subject. Almost all Rmail
commands are valid in the summary buffer also; these apply to the
message described by the current line of the summary. Moving point in
the summary buffer selects messages as you move to their summary lines.
A summary buffer applies to a single Rmail file only; if you are
editing multiple Rmail files, each one can have its own summary buffer.
The summary buffer name is made by appending `-summary' to the Rmail
buffer's name. Normally only one summary buffer is displayed at a time.
Making Summaries
----------------
Here are the commands to create a summary for the current Rmail file.
Once the Rmail file has a summary buffer, changes in the Rmail file
(such as deleting or expunging messages, and getting new mail)
automatically update the summary.
`h'
`C-M-h'
Summarize all messages (`rmail-summary').
`l LABELS <RET>'
`C-M-l LABELS <RET>'
Summarize messages that have one or more of the specified labels
(`rmail-summary-by-labels').
`C-M-r RCPTS <RET>'
Summarize messages that have one or more of the specified
recipients (`rmail-summary-by-recipients').
`C-M-t TOPIC <RET>'
Summarize messages that have a match for the specified regexp
TOPIC in their subjects (`rmail-summary-by-topic').
The `h' or `C-M-h' (`rmail-summary') command fills the summary buffer
for the current Rmail file with a summary of all the messages in the
file. It then displays and selects the summary buffer in another
window.
`C-M-l LABELS <RET>' (`rmail-summary-by-labels') makes a partial
summary mentioning only the messages that have one or more of the
labels LABELS. LABELS should contain label names separated by commas.
`C-M-r RCPTS <RET>' (`rmail-summary-by-recipients') makes a partial
summary mentioning only the messages that have one or more of the
recipients RCPTS. RCPTS should contain mailing addresses separated by
commas.
`C-M-t TOPIC <RET>' (`rmail-summary-by-topic') makes a partial
summary mentioning only the messages whose subjects have a match for
the regular expression TOPIC.
Note that there is only one summary buffer for any Rmail file;
making one kind of summary discards any previously made summary.
The variable `rmail-summary-window-size' says how many lines to use
for the summary window. The variable `rmail-summary-line-count-flag'
controls whether the summary line for a message should include the line
count of the message.
Editing in Summaries
--------------------
You can use the Rmail summary buffer to do almost anything you can do
in the Rmail buffer itself. In fact, once you have a summary buffer,
there's no need to switch back to the Rmail buffer.
You can select and display various messages in the Rmail buffer, from
the summary buffer, just by moving point in the summary buffer to
different lines. It doesn't matter what Emacs command you use to move
point; whichever line point is on at the end of the command, that
message is selected in the Rmail buffer.
Almost all Rmail commands work in the summary buffer as well as in
the Rmail buffer. Thus, `d' in the summary buffer deletes the current
message, `u' undeletes, and `x' expunges. `o' and `C-o' output the
current message to a file; `r' starts a reply to it. You can scroll
the current message while remaining in the summary buffer using <SPC>
and <DEL>.
The Rmail commands to move between messages also work in the summary
buffer, but with a twist: they move through the set of messages included
in the summary. They also ensure the Rmail buffer appears on the screen
(unlike cursor motion commands, which update the contents of the Rmail
buffer but don't display it in a window unless it already appears).
Here is a list of these commands:
`n'
Move to next line, skipping lines saying `deleted', and select its
message.
`p'
Move to previous line, skipping lines saying `deleted', and select
its message.
`M-n'
Move to next line and select its message.
`M-p'
Move to previous line and select its message.
`>'
Move to the last line, and select its message.
`<'
Move to the first line, and select its message.
`M-s PATTERN <RET>'
Search through messages for PATTERN starting with the current
message; select the message found, and move point in the summary
buffer to that message's line.
Deletion, undeletion, and getting new mail, and even selection of a
different message all update the summary buffer when you do them in the
Rmail buffer. If the variable `rmail-redisplay-summary' is non-`nil',
these actions also bring the summary buffer back onto the screen.
When you are finished using the summary, type `Q'
(`rmail-summary-wipe') to delete the summary buffer's window. You can
also exit Rmail while in the summary: `q' (`rmail-summary-quit')
deletes the summary window, then exits from Rmail by saving the Rmail
file and switching to another buffer.
Sorting the Rmail File
======================
`M-x rmail-sort-by-date'
Sort messages of current Rmail file by date.
`M-x rmail-sort-by-subject'
Sort messages of current Rmail file by subject.
`M-x rmail-sort-by-author'
Sort messages of current Rmail file by author's name.
`M-x rmail-sort-by-recipient'
Sort messages of current Rmail file by recipient's names.
`M-x rmail-sort-by-correspondent'
Sort messages of current Rmail file by the name of the other
correspondent.
`M-x rmail-sort-by-lines'
Sort messages of current Rmail file by size (number of lines).
`M-x rmail-sort-by-keywords <RET> LABELS <RET>'
Sort messages of current Rmail file by labels. The argument
LABELS should be a comma-separated list of labels. The order of
these labels specifies the order of messages; messages with the
first label come first, messages with the second label come
second, and so on. Messages which have none of these labels come
last.
The Rmail sort commands perform a *stable sort*: if there is no
reason to prefer either one of two messages, their order remains
unchanged. You can use this to sort by more than one criterion. For
example, if you use `rmail-sort-by-date' and then
`rmail-sort-by-author', messages from the same author appear in order
by date.
With a numeric argument, all these commands reverse the order of
comparison. This means they sort messages from newest to oldest, from
biggest to smallest, or in reverse alphabetical order.
Display of Messages
===================
Rmail reformats the header of each message before displaying it for
the first time. Reformatting hides uninteresting header fields to
reduce clutter. You can use the `t' command to show the entire header
or to repeat the header reformatting operation.
`t'
Toggle display of complete header (`rmail-toggle-header').
Reformatting the header involves deleting most header fields, on the
grounds that they are not interesting. The variable
`rmail-ignored-headers' holds a regular expression that specifies which
header fields to hide in this way--if it matches the beginning of a
header field, that whole field is hidden.
Rmail saves the complete original header before reformatting; to see
it, use the `t' command (`rmail-toggle-header'). This discards the
reformatted headers of the current message and displays it with the
original header. Repeating `t' reformats the message again. Selecting
the message again also reformats.
One consequence of this is that if you edit the reformatted header
(using `e'; *note Rmail Editing::.), subsequent use of `t' will discard
your edits. On the other hand, if you use `e' after `t', to edit the
original (unreformatted) header, those changes are permanent.
When the `t' command has a prefix argument, a positive argument
means to show the reformatted header, and a zero or negative argument
means to show the full header.
When used with a window system that supports multiple fonts, Rmail
highlights certain header fields that are especially interesting--by
default, the `From' and `Subject' fields. The variable
`rmail-highlighted-headers' holds a regular expression that specifies
the header fields to highlight; if it matches the beginning of a header
field, that whole field is highlighted.
If you specify unusual colors for your text foreground and
background, the colors used for highlighting may not go well with them.
If so, specify different colors for the `highlight' face. That is
worth doing because the `highlight' face is used for other kinds of
highlighting as well. *Note Faces::, for how to do this.
To turn off highlighting entirely in Rmail, set
`rmail-highlighted-headers' to `nil'.
Editing Within a Message
========================
Most of the usual Emacs commands are available in Rmail mode, though
a few, such as `C-M-n' and `C-M-h', are redefined by Rmail for other
purposes. However, the Rmail buffer is normally read only, and most of
the letters are redefined as Rmail commands. If you want to edit the
text of a message, you must use the Rmail command `e'.
`e'
Edit the current message as ordinary text.
The `e' command (`rmail-edit-current-message') switches from Rmail
mode into Rmail Edit mode, another major mode which is nearly the same
as Text mode. The mode line indicates this change.
In Rmail Edit mode, letters insert themselves as usual and the Rmail
commands are not available. When you are finished editing the message
and are ready to go back to Rmail, type `C-c C-c', which switches back
to Rmail mode. Alternatively, you can return to Rmail mode but cancel
all the editing that you have done, by typing `C-c C-]'.
Entering Rmail Edit mode runs the hook `text-mode-hook'; then it
runs the hook `rmail-edit-mode-hook' (*note Hooks::.). It adds the
attribute `edited' to the message. It also displays the full headers
of the message, so that you can edit the headers as well as the body of
the message, and your changes in the the headers will be permanent.
Digest Messages
===============
A "digest message" is a message which exists to contain and carry
several other messages. Digests are used on some moderated mailing
lists; all the messages that arrive for the list during a period of time
such as one day are put inside a single digest which is then sent to the
subscribers. Transmitting the single digest uses much less computer
time than transmitting the individual messages even though the total
size is the same, because the per-message overhead in network mail
transmission is considerable.
When you receive a digest message, the most convenient way to read
it is to "undigestify" it: to turn it back into many individual
messages. Then you can read and delete the individual messages as it
suits you.
To do this, select the digest message and type the command `M-x
undigestify-rmail-message'. This extracts the submessages as separate
Rmail messages, and inserts them following the digest. The digest
message itself is flagged as deleted.
Converting an Rmail File to Inbox Format
========================================
The command `M-x unrmail' converts a file in Rmail format to inbox
format (also known as the system mailbox format), so that you can use it
with other mail-editing tools. You must specify two arguments, the name
of the Rmail file and the name to use for the converted file. `M-x
unrmail' does not alter the Rmail file itself.
Reading Rot13 Messages
======================
Mailing list messages that might offend some readers are sometimes
encoded in a simple code called "rot13"--so named because it rotates
the alphabet by 13 letters. This code is not for secrecy, as it
provides none; rather, it enables those who might be offended to avoid
ever seeing the real text of the message.
To view a buffer using the rot13 code, use the command `M-x
rot13-other-window'. This displays the current buffer in another window
which applies the code when displaying the text.
`movemail' and POP
==================
When getting new mail, Rmail first copies the new mail from the inbox
file to the Rmail file; then it saves the Rmail file; then it truncates
the inbox file. This way, a system crash may cause duplication of mail
between the inbox and the Rmail file, but cannot lose mail. If
`rmail-preserve-inbox' is non-`nil', then Rmail will copy new mail from
the inbox file to the Rmail file without truncating the inbox file.
You may wish to set this, for example, on a portable computer you use
to check your mail via POP while traveling, so that your mail will
remain on the server and you can save it later on your workstation.
In some cases, Rmail copies the new mail from the inbox file
indirectly. First it runs the `movemail' program to move the mail from
the inbox to an intermediate file called `~/.newmail-INBOXNAME'. Then
Rmail merges the new mail from that file, saves the Rmail file, and
only then deletes the intermediate file. If there is a crash at the
wrong time, this file continues to exist, and Rmail will use it again
the next time it gets new mail from that inbox.
If Rmail is unable to convert the data in `~/.newmail-INBOXNAME'
into Babyl format, it renames the file to `~/RMAILOSE.N' (N is an
integer chosen to make the name unique) so that Rmail will not have
trouble with the data again. You should look at the file, find
whatever message confuses Rmail (probably one that includes the
control-underscore character, octal code 037), and delete it. Then you
can use `1 g' to get new mail from the corrected file.
Some sites use a method called POP for accessing users' inbox data
instead of storing the data in inbox files. `movemail' can work with
POP if you compile it with the macro `MAIL_USE_POP' defined. (You can
achieve that by specifying `--with-pop' when you run `configure' during
the installation of Emacs.) `movemail' only works with POP3, not with
older versions of POP.
Assuming you have compiled and installed `movemail' appropriately,
you can specify a POP inbox by using a "file name" of the form
`po:USERNAME', in the inbox list of an Rmail file. `movemail' handles
such a name by opening a connection to the POP server. The `MAILHOST'
environment variable specifies the machine to look for the server on.
Accessing mail via POP may require a password. If the variable
`rmail-pop-password' is non-`nil', it specifies the password to use for
POP. Alternatively, if `rmail-pop-password-required' is non-`nil',
then Rmail asks you for the password to use.
If you need to pass additional command-line flags to `movemail', set
the variable `rmail-movemail-flags' a list of the flags you wish to
use. Do not use this variable to pass the `-p' flag to preserve your
inbox contents; use `rmail-preserve-inbox' instead.
The `movemail' program installed at your site may support Kerberos
authentication. If it is supported, it is used by default whenever you
attempt to retrieve POP mail when `rmail-pop-password' and
`rmail-pop-password-required' are unset.
Some POP servers store messages in reverse order. If your server
does this, and you would rather read your mail in the order in which it
was received, you can tell `movemail' to reverse the order of
downloaded messages by adding the `-r' flag to `rmail-movemail-flags'.
Dired, the Directory Editor
***************************
Dired makes an Emacs buffer containing a listing of a directory, and
optionally some of its subdirectories as well. You can use the normal
Emacs commands to move around in this buffer, and special Dired commands
to operate on the files listed.
Entering Dired
==============
To invoke Dired, do `C-x d' or `M-x dired'. The command reads a
directory name or wildcard file name pattern as a minibuffer argument
to specify which files to list. Where `dired' differs from
`list-directory' is in putting the buffer into Dired mode so that the
special commands of Dired are available.
The variable `dired-listing-switches' specifies the options to give
to `ls' for listing directory; this string *must* contain `-l'. If you
use a numeric prefix argument with the `dired' command, you can specify
the `ls' switches with the minibuffer before you enter the directory
specification.
To display the Dired buffer in another window rather than in the
selected window, use `C-x 4 d' (`dired-other-window') instead of `C-x
d'. `C-x 5 d' (`dired-other-frame') uses a separate frame to display
the Dired buffer.
Commands in the Dired Buffer
============================
The Dired buffer is "read-only," and inserting text in it is not
useful, so ordinary printing characters such as `d' and `x' are used
for special Dired commands. Some Dired commands "mark" or "flag" the
"current file" (that is, the file on the current line); other commands
operate on the marked files or on the flagged files.
All the usual Emacs cursor motion commands are available in Dired
buffers. Some special-purpose cursor motion commands are also
provided. The keys `C-n' and `C-p' are redefined to put the cursor at
the beginning of the file name on the line, rather than at the
beginning of the line.
For extra convenience, <SPC> and `n' in Dired are equivalent to
`C-n'. `p' is equivalent to `C-p'. (Moving by lines is so common in
Dired that it deserves to be easy to type.) <DEL> (move up and unflag)
is often useful simply for moving up.
Deleting Files with Dired
=========================
The primary use of Dired is to "flag" files for deletion and then
delete the files previously flagged.
`d'
Flag this file for deletion.
`u'
Remove deletion flag on this line.
`<DEL>'
Move point to previous line and remove the deletion flag on that
line.
`x'
Delete the files that are flagged for deletion.
You can flag a file for deletion by moving to the line describing the
file and typing `d' (`dired-flag-file-deletion'). The deletion flag is
visible as a `D' at the beginning of the line. This command moves
point to the next line, so that repeated `d' commands flag successive
files. A numeric argument serves as a repeat count.
The files are flagged for deletion rather than deleted immediately to
reduce the danger of deleting a file accidentally. Until you direct
Dired to expunge the flagged files, you can remove deletion flags using
the commands `u' and <DEL>. `u' (`dired-unmark') works just like `d',
but removes flags rather than making flags. <DEL>
(`dired-unmark-backward') moves upward, removing flags; it is like `u'
with argument -1.
To delete the flagged files, type `x' (`dired-expunge'). This
command first displays a list of all the file names flagged for
deletion, and requests confirmation with `yes'. If you confirm, Dired
deletes the flagged files, then deletes their lines from the text of
the Dired buffer. The shortened Dired buffer remains selected.
If you answer `no' or quit with `C-g' when asked to confirm, you
return immediately to Dired, with the deletion flags still present in
the buffer, and no files actually deleted.
Flagging Many Files at Once
===========================
`#'
Flag all auto-save files (files whose names start and end with `#')
for deletion (*note Auto Save::.).
`~'
Flag all backup files (files whose names end with `~') for deletion
(*note Backup::.).
`&'
Flag for deletion all files with certain kinds of names, names that
suggest you could easily create the files again.
`. (Period)'
Flag excess numeric backup files for deletion. The oldest and
newest few backup files of any one file are exempt; the middle
ones are flagged.
`% d REGEXP <RET>'
Flag for deletion all files whose names match the regular
expression REGEXP.
The `#', `~', `&', and `.' commands flag many files for deletion,
based on their file names. These commands are useful precisely because
they do not themselves delete any files; you can remove the deletion
flags from any flagged files that you really wish to keep.
`&' (`dired-flag-garbage-files') flags files whose names match the
regular expression specified by the variable
`dired-garbage-files-regexp'. By default, this matches certain files
produced by TeX, and the `.orig' and `.rej' files produced by `patch'.
`#' (`dired-flag-auto-save-files') flags for deletion all files
whose names look like auto-save files (*note Auto Save::.)--that is,
files whose names begin and end with `#'. `~'
(`dired-flag-backup-files') flags for deletion all files whose names
say they are backup files (*note Backup::.)--that is, whose names end
in `~'.
`.' (period, `dired-clean-directory') flags just some of the backup
files for deletion: all but the oldest few and newest few backups of
any one file. Normally `dired-kept-versions' (*not*
`kept-new-versions'; that applies only when saving) specifies the
number of newest versions of each file to keep, and `kept-old-versions'
specifies the number of oldest versions to keep.
Period with a positive numeric argument, as in `C-u 3 .', specifies
the number of newest versions to keep, overriding
`dired-kept-versions'. A negative numeric argument overrides
`kept-old-versions', using minus the value of the argument to specify
the number of oldest versions of each file to keep.
The `% d' command flags all files whose names match a specified
regular expression (`dired-flag-files-regexp'). Only the non-directory
part of the file name is used in matching. You can use `^' and `$' to
anchor matches. You can exclude subdirectories by hiding them (*note
Hiding Subdirectories::.).
Visiting Files in Dired
=======================
There are several Dired commands for visiting or examining the files
listed in the Dired buffer. All of them apply to the current line's
file; if that file is really a directory, these commands invoke Dired on
that subdirectory (making a separate Dired buffer).
`f'
Visit the file described on the current line, like typing `C-x C-f'
and supplying that file name (`dired-find-file'). *Note
Visiting::.
`<RET>'
Equivalent to `f'.
`o'
Like `f', but uses another window to display the file's buffer
(`dired-find-file-other-window'). The Dired buffer remains visible
in the first window. This is like using `C-x 4 C-f' to visit the
file. *Note Windows::.
`C-o'
Visit the file described on the current line, and display the
buffer in another window, but do not select that window
(`dired-display-file').
`Mouse-2'
Visit the file named by the line you click on
(`dired-mouse-find-file-other-window'). This uses another window
to display the file, like the `o' command.
`v'
View the file described on the current line, using `M-x view-file'
(`dired-view-file').
Viewing a file is like visiting it, but is slanted toward moving
around in the file conveniently and does not allow changing the
file. *Note View File: Misc File Ops.
Dired Marks vs. Flags
=====================
Instead of flagging a file with `D', you can "mark" the file with
some other character (usually `*'). Most Dired commands to operate on
files, aside from "expunge" (`x'), look for files marked with `*'.
Here are some commands for marking with `*', or for unmarking or
operating on marks. (*Note Dired Deletion::, for commands to flag and
unflag files.)
`m'
`* m'
Mark the current file with `*' (`dired-mark'). With a numeric
argument N, mark the next N files starting with the current file.
(If N is negative, mark the previous -N files.)
`* *'
Mark all executable files with `*' (`dired-mark-executables').
With a numeric argument, unmark all those files.
`* @'
Mark all symbolic links with `*' (`dired-mark-symlinks'). With a
numeric argument, unmark all those files.
`* /'
Mark with `*' all files which are actually directories, except for
`.' and `..' (`dired-mark-directories'). With a numeric argument,
unmark all those files.
`* s'
Mark all the files in the current subdirectory, aside from `.'
and `..' (`dired-mark-subdir-files').
`u'
`* u'
Remove any mark on this line (`dired-unmark').
`<DEL>'
`* <DEL>'
Move point to previous line and remove any mark on that line
(`dired-unmark-backward').
`* !'
Remove all marks from all the files in this Dired buffer
(`dired-unmark-all-files-no-query').
`* ? MARKCHAR'
Remove all marks that use the character MARKCHAR
(`dired-unmark-all-files'). The argument is a single
character--do not use <RET> to terminate it.
With a numeric argument, this command queries about each marked
file, asking whether to remove its mark. You can answer `y'
meaning yes, `n' meaning no, or `!' to remove the marks from the
remaining files without asking about them.
`* C-n'
Move down to the next marked file (`dired-next-marked-file') A
file is "marked" if it has any kind of mark.
`* C-p'
Move up to the previous marked file (`dired-prev-marked-file')
`* t'
Toggle all marks (`dired-do-toggle'): files marked with `*' become
unmarked, and unmarked files are marked with `*'. Files marked in
any other way are not affected.
`* c OLD NEW'
Replace all marks that use the character OLD with marks that use
the character NEW (`dired-change-marks'). This command is the
primary way to create or use marks other than `*' or `D'. The
arguments are single characters--do not use <RET> to terminate
them.
You can use almost any character as a mark character by means of
this command, to distinguish various classes of files. If OLD is a
space (` '), then the command operates on all unmarked files; if
NEW is a space, then the command unmarks the files it acts on.
To illustrate the power of this command, here is how to put `D'
flags on all the files that have no marks, while unflagging all
those that already have `D' flags:
* c D t * c SPC D * c t SPC
This assumes that no files are marked with `t'.
`% m REGEXP <RET>'
`* % REGEXP <RET>'
Mark (with `*') all files whose names match the regular expression
REGEXP (`dired-mark-files-regexp'). This command is like `% d',
except that it marks files with `*' instead of flagging with `D'.
*Note Flagging Many Files::.
Only the non-directory part of the file name is used in matching.
Use `^' and `$' to anchor matches. Exclude subdirectories by
hiding them (*note Hiding Subdirectories::.).
`% g REGEXP <RET>'
Mark (with `*') all files whose *contents* contain a match for the
regular expression REGEXP (`dired-mark-files-containing-regexp').
This command is like `% m', except that it searches the file
contents instead of the file name.
`C-_'
Undo changes in the Dired buffer, such as adding or removing marks
(`dired-undo').
Operating on Files
==================
This section describes the basic Dired commands to operate on one
file or several files. All of these commands are capital letters; all
of them use the minibuffer, either to read an argument or to ask for
confirmation, before they act. All of them give you several ways to
specify which files to manipulate:
* If you give the command a numeric prefix argument N, it operates
on the next N files, starting with the current file. (If N is
negative, the command operates on the -N files preceding the
current line.)
* Otherwise, if some files are marked with `*', the command operates
on all those files.
* Otherwise, the command operates on the current file only.
Here are the file-manipulating commands that operate on files in this
way. (Some other Dired commands, such as `!' and the `%' commands,
also use these conventions to decide which files to work on.)
`C NEW <RET>'
Copy the specified files (`dired-do-copy'). The argument NEW is
the directory to copy into, or (if copying a single file) the new
name.
If `dired-copy-preserve-time' is non-`nil', then copying with this
command sets the modification time of the new file to be the same
as that of the old file.
`D'
Delete the specified files (`dired-do-delete'). Like the other
commands in this section, this command operates on the *marked*
files, or the next N files. By contrast, `x' (`dired-expunge')
deletes all "flagged" files.
`R NEW <RET>'
Rename the specified files (`dired-do-rename'). The argument NEW
is the directory to rename into, or (if renaming a single file)
the new name.
Dired automatically changes the visited file name of buffers
associated with renamed files so that they refer to the new names.
`H NEW <RET>'
Make hard links to the specified files (`dired-do-hardlink'). The
argument NEW is the directory to make the links in, or (if making
just one link) the name to give the link.
`S NEW <RET>'
Make symbolic links to the specified files (`dired-do-symlink').
The argument NEW is the directory to make the links in, or (if
making just one link) the name to give the link.
`M MODESPEC <RET>'
Change the mode (also called "permission bits") of the specified
files (`dired-do-chmod'). This uses the `chmod' program, so
MODESPEC can be any argument that `chmod' can handle.
`G NEWGROUP <RET>'
Change the group of the specified files to NEWGROUP
(`dired-do-chgrp').
`O NEWOWNER <RET>'
Change the owner of the specified files to NEWOWNER
(`dired-do-chown'). (On most systems, only the superuser can do
this.)
The variable `dired-chown-program' specifies the name of the
program to use to do the work (different systems put `chown' in
different places).
`P COMMAND <RET>'
Print the specified files (`dired-do-print'). You must specify the
command to print them with, but the minibuffer starts out with a
suitable guess made using the variables `lpr-command' and
`lpr-switches' (the same variables that `lpr-buffer' uses; *note
Hardcopy::.).
`Z'
Compress the specified files (`dired-do-compress'). If the file
appears to be a compressed file already, it is uncompressed
instead.
`L'
Load the specified Emacs Lisp files (`dired-do-load'). *Note Lisp
Libraries::.
`B'
Byte compile the specified Emacs Lisp files
(`dired-do-byte-compile'). *Note Byte Compilation: (elisp)Byte
Compilation.
`A REGEXP <RET>'
Search all the specified files for the regular expression REGEXP
(`dired-do-search').
This command is a variant of `tags-search'. The search stops at
the first match it finds; use `M-,' to resume the search and find
the next match. *Note Tags Search::.
`Q FROM <RET> TO <RET>'
Perform `query-replace-regexp' on each of the specified files,
replacing matches for FROM (a regular expression) with the string
TO (`dired-do-query-replace').
This command is a variant of `tags-query-replace'. If you exit the
query replace loop, you can use `M-,' to resume the scan and
replace more matches. *Note Tags Search::.
One special file-operation command is `+'
(`dired-create-directory'). This command reads a directory name and
creates the directory if it does not already exist.
Shell Commands in Dired
=======================
The dired command `!' (`dired-do-shell-command') reads a shell
command string in the minibuffer and runs that shell command on all the
specified files. You can specify the files to operate on in the usual
ways for Dired commands (*note Operating on Files::.). There are two
ways of applying a shell command to multiple files:
* If you use `*' in the shell command, then it runs just once, with
the list of file names substituted for the `*'. The order of file
names is the order of appearance in the Dired buffer.
Thus, `! tar cf foo.tar * <RET>' runs `tar' on the entire list of
file names, putting them into one tar file `foo.tar'.
* If the command string doesn't contain `*', then it runs once *for
each file*, with the file name added at the end.
For example, `! uudecode <RET>' runs `uudecode' on each file.
What if you want to run the shell command once for each file but with
the file name inserted in the middle? Or if you want to use the file
names in a more complicated fashion? Use a shell loop. For example,
this shell command would run `uuencode' on each of the specified files,
writing the output into a corresponding `.uu' file:
for file in *; do uuencode $file $file >$file.uu; done
The working directory for the shell command is the top-level
directory of the Dired buffer.
The `!' command does not attempt to update the Dired buffer to show
new or modified files, because it doesn't really understand shell
commands, and does not know what files the shell command changed. Use
the `g' command to update the Dired buffer (*note Dired Updating::.).
Transforming File Names in Dired
================================
Here are commands that alter file names in a systematic way:
`% u'
Rename each of the selected files to an upper-case name
(`dired-upcase'). If the old file names are `Foo' and `bar', the
new names are `FOO' and `BAR'.
`% l'
Rename each of the selected files to a lower-case name
(`dired-downcase'). If the old file names are `Foo' and `bar',
the new names are `foo' and `bar'.
`% R FROM <RET> TO <RET>'
`% C FROM <RET> TO <RET>'
`% H FROM <RET> TO <RET>'
`% S FROM <RET> TO <RET>'
These four commands rename, copy, make hard links and make soft
links, in each case computing the new name by regular-expression
substitution from the name of the old file.
The four regular-expression substitution commands effectively perform
a search-and-replace on the selected file names in the Dired buffer.
They read two arguments: a regular expression FROM, and a substitution
pattern TO.
The commands match each "old" file name against the regular
expression FROM, and then replace the matching part with TO. You can
use `\&' and `\DIGIT' in TO to refer to all or part of what the pattern
matched in the old file name, as in `replace-regexp' (*note Regexp
Replace::.). If the regular expression matches more than once in a
file name, only the first match is replaced.
For example, `% R ^.*$ <RET> x-\& <RET>' renames each selected file
by prepending `x-' to its name. The inverse of this, removing `x-'
from the front of each file name, is also possible: one method is `% R
^x-\(.*\)$ <RET> \1 <RET>'; another is `% R ^x- <RET> <RET>'. (Use `^'
and `$' to anchor matches that should span the whole filename.)
Normally, the replacement process does not consider the files'
directory names; it operates on the file name within the directory. If
you specify a numeric argument of zero, then replacement affects the
entire absolute file name including directory name.
Often you will want to select the set of files to operate on using
the same REGEXP that you will use to operate on them. To do this, mark
those files with `% m REGEXP <RET>', then use the same regular
expression in the command to operate on the files. To make this
easier, the `%' commands to operate on files use the last regular
expression specified in any `%' command as a default.
File Comparison with Dired
==========================
Here are two Dired commands that compare specified files using
`diff'.
`='
Compare the current file (the file at point) with another file
(the file at the mark) using the `diff' program (`dired-diff').
The file at the mark is the first argument of `diff', and the file
at point is the second argument.
`M-='
Compare the current file with its latest backup file
(`dired-backup-diff'). If the current file is itself a backup,
compare it with the file it is a backup of; this way, you can
compare a file with any backup version of your choice.
The backup file is the first file given to `diff'.
Subdirectories in Dired
=======================
A Dired buffer displays just one directory in the normal case; but
you can optionally include its subdirectories as well.
The simplest way to include multiple directories in one Dired buffer
is to specify the options `-lR' for running `ls'. (If you give a
numeric argument when you run Dired, then you can specify these options
in the minibuffer.) That produces a recursive directory listing showing
all subdirectories at all levels.
But usually all the subdirectories are too many; usually you will
prefer to include specific subdirectories only. You can do this with
the `i' command:
`i'
Insert the contents of a subdirectory later in the buffer.
Use the `i' (`dired-maybe-insert-subdir') command on a line that
describes a file which is a directory. It inserts the contents of that
directory into the same Dired buffer, and moves there. Inserted
subdirectory contents follow the top-level directory of the Dired
buffer, just as they do in `ls -lR' output.
If the subdirectory's contents are already present in the buffer, the
`i' command just moves to it.
In either case, `i' sets the Emacs mark before moving, so `C-u
C-<SPC>' takes you back to the old position in the buffer (the line
describing that subdirectory).
Use the `l' command (`dired-do-redisplay') to update the
subdirectory's contents. Use `k' to delete the subdirectory. *Note
Dired Updating::.
Moving Over Subdirectories
==========================
When a Dired buffer lists subdirectories, you can use the page motion
commands `C-x [' and `C-x ]' to move by entire directories.
The following commands move across, up and down in the tree of
directories within one Dired buffer. They move to "directory header
lines", which are the lines that give a directory's name, at the
beginning of the directory's contents.
`C-M-n'
Go to next subdirectory header line, regardless of level
(`dired-next-subdir').
`C-M-p'
Go to previous subdirectory header line, regardless of level
(`dired-prev-subdir').
`C-M-u'
Go up to the parent directory's header line (`dired-tree-up').
`C-M-d'
Go down in the directory tree, to the first subdirectory's header
line (`dired-tree-down').
`<'
Move up to the previous directory-file line (`dired-prev-dirline').
These lines are the ones that describe a directory as a file in its
parent directory.
`>'
Move down to the next directory-file line (`dired-prev-dirline').
Hiding Subdirectories
=====================
"Hiding" a subdirectory means to make it invisible, except for its
header line, via selective display (*note Selective Display::.).
`$'
Hide or reveal the subdirectory that point is in, and move point
to the next subdirectory (`dired-hide-subdir'). A numeric
argument serves as a repeat count.
`M-$'
Hide all subdirectories in this Dired buffer, leaving only their
header lines (`dired-hide-all'). Or, if any subdirectory is
currently hidden, make all subdirectories visible again. You can
use this command to get an overview in very deep directory trees
or to move quickly to subdirectories far away.
Ordinary Dired commands never consider files inside a hidden
subdirectory. For example, the commands to operate on marked files
ignore files in hidden directories even if they are marked. Thus you
can use hiding to temporarily exclude subdirectories from operations
without having to remove the markers.
The subdirectory hiding commands toggle; that is, they hide what was
visible, and show what was hidden.
Updating the Dired Buffer
=========================
This section describes commands to update the Dired buffer to reflect
outside (non-Dired) changes in the directories and files, and to delete
part of the Dired buffer.
`g'
Update the entire contents of the Dired buffer (`revert-buffer').
`l'
Update the specified files (`dired-do-redisplay').
`k'
Delete the specified *file lines*--not the files, just the lines
(`dired-do-kill-lines').
`s'
Toggle between alphabetical order and date/time order
(`dired-sort-toggle-or-edit').
`C-u s SWITCHES <RET>'
Refresh the Dired buffer using SWITCHES as
`dired-listing-switches'.
Type `g' (`revert-buffer') to update the contents of the Dired
buffer, based on changes in the files and directories listed. This
preserves all marks except for those on files that have vanished.
Hidden subdirectories are updated but remain hidden.
To update only some of the files, type `l' (`dired-do-redisplay').
This command applies to the next N files, or to the marked files if
any, or to the current file. Updating them means reading their current
status from the file system and changing the buffer to reflect it
properly.
If you use `l' on a subdirectory header line, it updates the
contents of the corresponding subdirectory.
To delete the specified *file lines*--not the files, just the
lines--type `k' (`dired-do-kill-lines'). With a numeric argument N,
this command applies to the next N files; otherwise, it applies to the
marked files.
If you kill the line for a file that is a directory, the directory's
contents are also deleted from the buffer. Typing `C-u k' on the
header line for a subdirectory is another way to delete a subdirectory
from the Dired buffer.
The `g' command brings back any individual lines that you have
killed in this way, but not subdirectories--you must use `i' to
reinsert each subdirectory.
The files in a Dired buffers are normally listed in alphabetical
order by file names. Alternatively Dired can sort them by date/time.
The Dired command `s' (`dired-sort-toggle-or-edit') switches between
these two sorting modes. The mode line in a Dired buffer indicates
which way it is currently sorted--by name, or by date.
`C-u s SWITCHES <RET>' lets you specify a new value for
`dired-listing-switches'.
Dired and `find'
================
You can select a set of files for display in a Dired buffer more
flexibly by using the `find' utility to choose the files.
To search for files with names matching a wildcard pattern use `M-x
find-name-dired'. It reads arguments DIRECTORY and PATTERN, and
chooses all the files in DIRECTORY or its subdirectories whose
individual names match PATTERN.
The files thus chosen are displayed in a Dired buffer in which the
ordinary Dired commands are available.
If you want to test the contents of files, rather than their names,
use `M-x find-grep-dired'. This command reads two minibuffer
arguments, DIRECTORY and REGEXP; it chooses all the files in DIRECTORY
or its subdirectories that contain a match for REGEXP. It works by
running the programs `find' and `grep'. See also `M-x grep-find', in
*Note Compilation::. Remember to write the regular expression for
`grep', not for Emacs.
The most general command in this series is `M-x find-dired', which
lets you specify any condition that `find' can test. It takes two
minibuffer arguments, DIRECTORY and FIND-ARGS; it runs `find' in
DIRECTORY, passing FIND-ARGS to tell `find' what condition to test. To
use this command, you need to know how to use `find'.
The format of listing produced by these commands is controlled by the
variable `find-ls-option', whose default value specifies using options
`-ld' for `ls'. If your listings are corrupted, you may need to change
the value of this variable.
The Calendar and the Diary
**************************
Emacs provides the functions of a desk calendar, with a diary of
planned or past events. To enter the calendar, type `M-x calendar';
this displays a three-month calendar centered on the current month, with
point on the current date. With a numeric argument, as in `C-u M-x
calendar', it prompts you for the month and year to be the center of the
three-month calendar. The calendar uses its own buffer, whose major
mode is Calendar mode.
`Mouse-2' in the calendar brings up a menu of operations on a
particular date; `C-Mouse-3' brings up a menu of commonly used calendar
features that are independent of any particular date. To exit the
calendar, type `q'. *Note Customizing the Calendar and Diary:
(elisp)Calendar, for customization information about the calendar and
diary.
Movement in the Calendar
========================
Calendar mode lets you move through the calendar in logical units of
time such as days, weeks, months, and years. If you move outside the
three months originally displayed, the calendar display "scrolls"
automatically through time to make the selected date visible. Moving to
a date lets you view its holidays or diary entries, or convert it to
other calendars; moving longer time periods is also useful simply to
scroll the calendar.
Motion by Standard Lengths of Time
----------------------------------
The commands for movement in the calendar buffer parallel the
commands for movement in text. You can move forward and backward by
days, weeks, months, and years.
`C-f'
Move point one day forward (`calendar-forward-day').
`C-b'
Move point one day backward (`calendar-backward-day').
`C-n'
Move point one week forward (`calendar-forward-week').
`C-p'
Move point one week backward (`calendar-backward-week').
`M-}'
Move point one month forward (`calendar-forward-month').
`M-{'
Move point one month backward (`calendar-backward-month').
`C-x ]'
Move point one year forward (`calendar-forward-year').
`C-x ['
Move point one year backward (`calendar-backward-year').
The day and week commands are natural analogues of the usual Emacs
commands for moving by characters and by lines. Just as `C-n' usually
moves to the same column in the following line, in Calendar mode it
moves to the same day in the following week. And `C-p' moves to the
same day in the previous week.
The arrow keys are equivalent to `C-f', `C-b', `C-n' and `C-p', just
as they normally are in other modes.
The commands for motion by months and years work like those for
weeks, but move a larger distance. The month commands `M-}' and `M-{'
move forward or backward by an entire month's time. The year commands
`C-x ]' and `C-x [' move forward or backward a whole year.
The easiest way to remember these commands is to consider months and
years analogous to paragraphs and pages of text, respectively. But the
commands themselves are not quite analogous. The ordinary Emacs
paragraph commands move to the beginning or end of a paragraph, whereas
these month and year commands move by an entire month or an entire
year, which usually involves skipping across the end of a month or year.
All these commands accept a numeric argument as a repeat count. For
convenience, the digit keys and the minus sign specify numeric
arguments in Calendar mode even without the Meta modifier. For example,
`100 C-f' moves point 100 days forward from its present location.
Beginning or End of Week, Month or Year
---------------------------------------
A week (or month, or year) is not just a quantity of days; we think
of weeks (months, years) as starting on particular dates. So Calendar
mode provides commands to move to the beginning or end of a week, month
or year:
`C-a'
Move point to start of week (`calendar-beginning-of-week').
`C-e'
Move point to end of week (`calendar-end-of-week').
`M-a'
Move point to start of month (`calendar-beginning-of-month').
`M-e'
Move point to end of month (`calendar-end-of-month').
`M-<'
Move point to start of year (`calendar-beginning-of-year').
`M->'
Move point to end of year (`calendar-end-of-year').
These commands also take numeric arguments as repeat counts, with the
repeat count indicating how many weeks, months, or years to move
backward or forward.
By default, weeks begin on Sunday. To make them begin on Monday
instead, set the variable `calendar-week-start-day' to 1.
Specified Dates
---------------
Calendar mode provides commands for moving to a particular date
specified in various ways.
`g d'
Move point to specified date (`calendar-goto-date').
`o'
Center calendar around specified month (`calendar-other-month').
`.'
Move point to today's date (`calendar-goto-today').
`g d' (`calendar-goto-date') prompts for a year, a month, and a day
of the month, and then moves to that date. Because the calendar
includes all dates from the beginning of the current era, you must type
the year in its entirety; that is, type `1990', not `90'.
`o' (`calendar-other-month') prompts for a month and year, then
centers the three-month calendar around that month.
You can return to today's date with `.' (`calendar-goto-today').
Scrolling in the Calendar
=========================
The calendar display scrolls automatically through time when you
move out of the visible portion. You can also scroll it manually.
Imagine that the calendar window contains a long strip of paper with
the months on it. Scrolling it means moving the strip so that new
months become visible in the window.
`C-x <'
Scroll calendar one month forward (`scroll-calendar-left').
`C-x >'
Scroll calendar one month backward (`scroll-calendar-right').
`C-v'
`<NEXT>'
Scroll calendar three months forward
(`scroll-calendar-left-three-months').
`M-v'
`<PRIOR>'
Scroll calendar three months backward
(`scroll-calendar-right-three-months').
The most basic calendar scroll commands scroll by one month at a
time. This means that there are two months of overlap between the
display before the command and the display after. `C-x <' scrolls the
calendar contents one month to the left; that is, it moves the display
forward in time. `C-x >' scrolls the contents to the right, which
moves backwards in time.
The commands `C-v' and `M-v' scroll the calendar by an entire
"screenful"--three months--in analogy with the usual meaning of these
commands. `C-v' makes later dates visible and `M-v' makes earlier
dates visible. These commands take a numeric argument as a repeat
count; in particular, since `C-u' multiplies the next command by four,
typing `C-u C-v' scrolls the calendar forward by a year and typing `C-u
M-v' scrolls the calendar backward by a year.
The function keys <NEXT> and <PRIOR> are equivalent to `C-v' and
`M-v', just as they are in other modes.
Counting Days
=============
`M-='
Display the number of days in the current region
(`calendar-count-days-region').
To determine the number of days in the region, type `M-='
(`calendar-count-days-region'). The numbers of days printed is
*inclusive*; that is, it includes the days specified by mark and point.
Miscellaneous Calendar Commands
===============================
`p d'
Display day-in-year (`calendar-print-day-of-year').
`C-c C-l'
Regenerate the calendar window (`redraw-calendar').
`SPC'
Scroll the next window (`scroll-other-window').
`q'
Exit from calendar (`exit-calendar').
To print the number of days elapsed since the start of the year, or
the number of days remaining in the year, type the `p d' command
(`calendar-print-day-of-year'). This displays both of those numbers in
the echo area. The number of days elapsed includes the selected date.
The number of days remaining does not include that date.
If the calendar window text gets corrupted, type `C-c C-l'
(`redraw-calendar') to redraw it. (This can only happen if you use
non-Calendar-mode editing commands.)
In Calendar mode, you can use `SPC' (`scroll-other-window') to
scroll the other window. This is handy when you display a list of
holidays or diary entries in another window.
To exit from the calendar, type `q' (`exit-calendar'). This buries
all buffers related to the calendar, selecting other buffers. (If a
frame contains a dedicated calendar window, exiting from the calendar
iconifies that frame.)
LaTeX Calendar
==============
The Calendar LaTeX commands produce a buffer of LaTeX code that
prints as a calendar. Depending on the command you use, the printed
calendar covers the day, week, month or year that point is in.
`t m'
Generate a one-month calendar (`cal-tex-cursor-month').
`t M'
Generate a sideways-printing one-month calendar
(`cal-tex-cursor-month-landscape').
`t d'
Generate a one-day calendar (`cal-tex-cursor-day').
`t w 1'
Generate a one-page calendar for one week (`cal-tex-cursor-week').
`t w 2'
Generate a two-page calendar for one week (`cal-tex-cursor-week2').
`t w 3'
Generate an ISO-style calendar for one week
(`cal-tex-cursor-week-iso').
`t w 4'
Generate a calendar for one Monday-starting week
(`cal-tex-cursor-week-monday').
`t f w'
Generate a Filofax-style two-weeks-at-a-glance calendar
(`cal-tex-cursor-filofax-2week').
`t f W'
Generate a Filofax-style one-week-at-a-glance calendar
(`cal-tex-cursor-filofax-week').
`t y'
Generate a calendar for one year (`cal-tex-cursor-year').
`t Y'
Generate a sideways-printing calendar for one year
(`cal-tex-cursor-year-landscape').
`t f y'
Generate a Filofax-style calendar for one year
(`cal-tex-cursor-filofax-year').
Some of these commands print the calendar sideways (in "landscape
mode"), so it can be wider than it is long. Some of them use Filofax
paper size (3.75in x 6.75in). All of these commands accept a prefix
argument which specifies how many days, weeks, months or years to print
(starting always with the selected one).
If the variable `cal-tex-holidays' is non-`nil' (the default), then
the printed calendars show the holidays in `calendar-holidays'. If the
variable `cal-tex-diary' is non-`nil' (the default is `nil'), diary
entries are included also (in weekly and monthly calendars only).
Holidays
========
The Emacs calendar knows about all major and many minor holidays,
and can display them.
`h'
Display holidays for the selected date
(`calendar-cursor-holidays').
`Mouse-2 Holidays'
Display any holidays for the date you click on.
`x'
Mark holidays in the calendar window (`mark-calendar-holidays').
`u'
Unmark calendar window (`calendar-unmark').
`a'
List all holidays for the displayed three months in another window
(`list-calendar-holidays').
`M-x holidays'
List all holidays for three months around today's date in another
window.
`M-x list-holidays'
List holidays in another window for a specified range of years.
To see if any holidays fall on a given date, position point on that
date in the calendar window and use the `h' command. Alternatively,
click on that date with `Mouse-2' and then choose `Holidays' from the
menu that appears. Either way, this displays the holidays for that
date, in the echo area if they fit there, otherwise in a separate
window.
To view the distribution of holidays for all the dates shown in the
calendar, use the `x' command. This displays the dates that are
holidays in a different face (or places a `*' after these dates, if
display with multiple faces is not available). The command applies both
to the currently visible months and to other months that subsequently
become visible by scrolling. To turn marking off and erase the current
marks, type `u', which also erases any diary marks (*note Diary::.).
To get even more detailed information, use the `a' command, which
displays a separate buffer containing a list of all holidays in the
current three-month range. You can use <SPC> in the calendar window to
scroll that list.
The command `M-x holidays' displays the list of holidays for the
current month and the preceding and succeeding months; this works even
if you don't have a calendar window. If you want the list of holidays
centered around a different month, use `C-u M-x holidays', which
prompts for the month and year.
The holidays known to Emacs include United States holidays and the
major Christian, Jewish, and Islamic holidays; also the solstices and
equinoxes.
The command `M-x list-holidays' displays the list of holidays for a
range of years. This function asks you for the starting and stopping
years, and allows you to choose all the holidays or one of several
categories of holidays. You can use this command even if you don't have
a calendar window.
The dates used by Emacs for holidays are based on *current
practice*, not historical fact. Historically, for instance, the start
of daylight savings time and even its existence have varied from year to
year, but present United States law mandates that daylight savings time
begins on the first Sunday in April. When the daylight savings rules
are set up for the United States, Emacs always uses the present
definition, even though it is wrong for some prior years.
Times of Sunrise and Sunset
===========================
Special calendar commands can tell you, to within a minute or two,
the times of sunrise and sunset for any date.
`S'
Display times of sunrise and sunset for the selected date
(`calendar-sunrise-sunset').
`Mouse-2 Sunrise/Sunset'
Display times of sunrise and sunset for the date you click on.
`M-x sunrise-sunset'
Display times of sunrise and sunset for today's date.
`C-u M-x sunrise-sunset'
Display times of sunrise and sunset for a specified date.
Within the calendar, to display the *local times* of sunrise and
sunset in the echo area, move point to the date you want, and type `S'.
Alternatively, click `Mouse-2' on the date, then choose
`Sunrise/Sunset' from the menu that appears. The command `M-x
sunrise-sunset' is available outside the calendar to display this
information for today's date or a specified date. To specify a date
other than today, use `C-u M-x sunrise-sunset', which prompts for the
year, month, and day.
You can display the times of sunrise and sunset for any location and
any date with `C-u C-u M-x sunrise-sunset'. This asks you for a
longitude, latitude, number of minutes difference from Coordinated
Universal Time, and date, and then tells you the times of sunrise and
sunset for that location on that date.
Because the times of sunrise and sunset depend on the location on
earth, you need to tell Emacs your latitude, longitude, and location
name before using these commands. Here is an example of what to set:
(setq calendar-latitude 40.1)
(setq calendar-longitude -88.2)
(setq calendar-location-name "Urbana, IL")
Use one decimal place in the values of `calendar-latitude' and
`calendar-longitude'.
Your time zone also affects the local time of sunrise and sunset.
Emacs usually gets time zone information from the operating system, but
if these values are not what you want (or if the operating system does
not supply them), you must set them yourself. Here is an example:
(setq calendar-time-zone -360)
(setq calendar-standard-time-zone-name "CST")
(setq calendar-daylight-time-zone-name "CDT")
The value of `calendar-time-zone' is the number of minutes difference
between your local standard time and Coordinated Universal Time
(Greenwich time). The values of `calendar-standard-time-zone-name' and
`calendar-daylight-time-zone-name' are the abbreviations used in your
time zone. Emacs displays the times of sunrise and sunset *corrected
for daylight savings time*. *Note Daylight Savings::, for how daylight
savings time is determined.
As a user, you might find it convenient to set the calendar location
variables for your usual physical location in your `.emacs' file. And
when you install Emacs on a machine, you can create a `default.el' file
which sets them properly for the typical location of most users of that
machine. *Note Init File::.
Phases of the Moon
==================
These calendar commands display the dates and times of the phases of
the moon (new moon, first quarter, full moon, last quarter). This
feature is useful for debugging problems that "depend on the phase of
the moon."
`M'
Display the dates and times for all the quarters of the moon for
the three-month period shown (`calendar-phases-of-moon').
`M-x phases-of-moon'
Display dates and times of the quarters of the moon for three
months around today's date.
Within the calendar, use the `M' command to display a separate
buffer of the phases of the moon for the current three-month range. The
dates and times listed are accurate to within a few minutes.
Outside the calendar, use the command `M-x phases-of-moon' to
display the list of the phases of the moon for the current month and the
preceding and succeeding months. For information about a different
month, use `C-u M-x phases-of-moon', which prompts for the month and
year.
The dates and times given for the phases of the moon are given in
local time (corrected for daylight savings, when appropriate); but if
the variable `calendar-time-zone' is void, Coordinated Universal Time
(the Greenwich time zone) is used. *Note Daylight Savings::.
Conversion To and From Other Calendars
======================================
The Emacs calendar displayed is *always* the Gregorian calendar,
sometimes called the "new style" calendar, which is used in most of the
world today. However, this calendar did not exist before the sixteenth
century and was not widely used before the eighteenth century; it did
not fully displace the Julian calendar and gain universal acceptance
until the early twentieth century. The Emacs calendar can display any
month since January, year 1 of the current era, but the calendar
displayed is the Gregorian, even for a date at which the Gregorian
calendar did not exist.
While Emacs cannot display other calendars, it can convert dates to
and from several other calendars.
Supported Calendar Systems
--------------------------
The ISO commercial calendar is used largely in Europe.
The Julian calendar, named after Julius Caesar, was the one used in
Europe throughout medieval times, and in many countries up until the
nineteenth century.
Astronomers use a simple counting of days elapsed since noon, Monday,
January 1, 4713 B.C. on the Julian calendar. The number of days elapsed
is called the *Julian day number* or the *Astronomical day number*.
The Hebrew calendar is used by tradition in the Jewish religion. The
Emacs calendar program uses the Hebrew calendar to determine the dates
of Jewish holidays. Hebrew calendar dates begin and end at sunset.
The Islamic calendar is used in many predominantly Islamic countries.
Emacs uses it to determine the dates of Islamic holidays. There is no
universal agreement in the Islamic world about the calendar; Emacs uses
a widely accepted version, but the precise dates of Islamic holidays
often depend on proclamation by religious authorities, not on
calculations. As a consequence, the actual dates of observance can vary
slightly from the dates computed by Emacs. Islamic calendar dates begin
and end at sunset.
The French Revolutionary calendar was created by the Jacobins after
the 1789 revolution, to represent a more secular and nature-based view
of the annual cycle, and to install a 10-day week in a rationalization
measure similar to the metric system. The French government officially
abandoned this calendar at the end of 1805.
The Maya of Central America used three separate, overlapping calendar
systems, the *long count*, the *tzolkin*, and the *haab*. Emacs knows
about all three of these calendars. Experts dispute the exact
correlation between the Mayan calendar and our calendar; Emacs uses the
Goodman-Martinez-Thompson correlation in its calculations.
The Copts use a calendar based on the ancient Egyptian solar
calendar. Their calendar consists of twelve 30-day months followed by
an extra five-day period. Once every fourth year they add a leap day
to this extra period to make it six days. The Ethiopic calendar is
identical in structure, but has different year numbers and month names.
The Persians use a solar calendar based on a design of Omar Khayyam.
Their calendar consists of twelve months of which the first six have 31
days, the next five have 30 days, and the last has 29 in ordinary years
and 30 in leap years. Leap years occur in a complicated pattern every
four or five years.
The Chinese calendar is a complicated system of lunar months arranged
into solar years. The years go in cycles of sixty, each year containing
either twelve months in an ordinary year or thirteen months in a leap
year; each month has either 29 or 30 days. Years, ordinary months, and
days are named by combining one of ten "celestial stems" with one of
twelve "terrestrial branches" for a total of sixty names that are
repeated in a cycle of sixty.
Converting To Other Calendars
-----------------------------
The following commands describe the selected date (the date at point)
in various other calendar systems:
`Mouse-2 Other Calendars'
Display the date that you click on, expressed in various other
calendars.
`p c'
Display ISO commercial calendar equivalent for selected day
(`calendar-print-iso-date').
`p j'
Display Julian date for selected day
(`calendar-print-julian-date').
`p a'
Display astronomical (Julian) day number for selected day
(`calendar-print-astro-day-number').
`p h'
Display Hebrew date for selected day
(`calendar-print-hebrew-date').
`p i'
Display Islamic date for selected day
(`calendar-print-islamic-date').
`p f'
Display French Revolutionary date for selected day
(`calendar-print-french-date').
`p C'
Display Chinese date for selected day
(`calendar-print-chinese-date').
`p k'
Display Coptic date for selected day
(`calendar-print-coptic-date').
`p e'
Display Ethiopic date for selected day
(`calendar-print-ethiopic-date').
`p p'
Display Persian date for selected day
(`calendar-print-persian-date').
`p m'
Display Mayan date for selected day (`calendar-print-mayan-date').
If you are using X, the easiest way to translate a date into other
calendars is to click on it with `Mouse-2', then choose `Other
Calendars' from the menu that appears. This displays the equivalent
forms of the date in all the calendars Emacs understands, in the form of
a menu. (Choosing an alternative from this menu doesn't actually do
anything--the menu is used only for display.)
Put point on the desired date of the Gregorian calendar, then type
the appropriate keys. The `p' is a mnemonic for "print" since Emacs
"prints" the equivalent date in the echo area.
Converting From Other Calendars
-------------------------------
You can use the other supported calendars to specify a date to move
to. This section describes the commands for doing this using calendars
other than Mayan; for the Mayan calendar, see the following section.
`g c'
Move to a date specified in the ISO commercial calendar
(`calendar-goto-iso-date').
`g j'
Move to a date specified in the Julian calendar
(`calendar-goto-julian-date').
`g a'
Move to a date specified in astronomical (Julian) day number
(`calendar-goto-astro-day-number').
`g h'
Move to a date specified in the Hebrew calendar
(`calendar-goto-hebrew-date').
`g i'
Move to a date specified in the Islamic calendar
(`calendar-goto-islamic-date').
`g f'
Move to a date specified in the French Revolutionary calendar
(`calendar-goto-french-date').
`g C'
Move to a date specified in the Chinese calendar
(`calendar-goto-chinese-date').
`g p'
Move to a date specified in the Persian calendar
(`calendar-goto-persian-date').
`g k'
Move to a date specified in the Coptic calendar
(`calendar-goto-coptic-date').
`g e'
Move to a date specified in the Ethiopic calendar
(`calendar-goto-ethiopic-date').
These commands ask you for a date on the other calendar, move point
to the Gregorian calendar date equivalent to that date, and display the
other calendar's date in the echo area. Emacs uses strict completion
(*note Completion::.) whenever it asks you to type a month name, so you
don't have to worry about the spelling of Hebrew, Islamic, or French
names.
One common question concerning the Hebrew calendar is the computation
of the anniversary of a date of death, called a "yahrzeit." The Emacs
calendar includes a facility for such calculations. If you are in the
calendar, the command `M-x list-yahrzeit-dates' asks you for a range of
years and then displays a list of the yahrzeit dates for those years
for the date given by point. If you are not in the calendar, this
command first asks you for the date of death and the range of years,
and then displays the list of yahrzeit dates.
Converting from the Mayan Calendar
----------------------------------
Here are the commands to select dates based on the Mayan calendar:
`g m l'
Move to a date specified by the long count calendar
(`calendar-goto-mayan-long-count-date').
`g m n t'
Move to the next occurrence of a place in the tzolkin calendar
(`calendar-next-tzolkin-date').
`g m p t'
Move to the previous occurrence of a place in the tzolkin calendar
(`calendar-previous-tzolkin-date').
`g m n h'
Move to the next occurrence of a place in the haab calendar
(`calendar-next-haab-date').
`g m p h'
Move to the previous occurrence of a place in the haab calendar
(`calendar-previous-haab-date').
`g m n c'
Move to the next occurrence of a place in the calendar round
(`calendar-next-calendar-round-date').
`g m p c'
Move to the previous occurrence of a place in the calendar round
(`calendar-previous-calendar-round-date').
To understand these commands, you need to understand the Mayan
calendars. The "long count" is a counting of days with these units:
1 kin = 1 day 1 uinal = 20 kin 1 tun = 18 uinal
1 katun = 20 tun 1 baktun = 20 katun
Thus, the long count date 12.16.11.16.6 means 12 baktun, 16 katun, 11
tun, 16 uinal, and 6 kin. The Emacs calendar can handle Mayan long
count dates as early as 7.17.18.13.1, but no earlier. When you use the
`g m l' command, type the Mayan long count date with the baktun, katun,
tun, uinal, and kin separated by periods.
The Mayan tzolkin calendar is a cycle of 260 days formed by a pair of
independent cycles of 13 and 20 days. Since this cycle repeats
endlessly, Emacs provides commands to move backward and forward to the
previous or next point in the cycle. Type `g m p t' to go to the
previous tzolkin date; Emacs asks you for a tzolkin date and moves point
to the previous occurrence of that date. Similarly, type `g m n t' to
go to the next occurrence of a tzolkin date.
The Mayan haab calendar is a cycle of 365 days arranged as 18 months
of 20 days each, followed a 5-day monthless period. Like the tzolkin
cycle, this cycle repeats endlessly, and there are commands to move
backward and forward to the previous or next point in the cycle. Type
`g m p h' to go to the previous haab date; Emacs asks you for a haab
date and moves point to the previous occurrence of that date.
Similarly, type `g m n h' to go to the next occurrence of a haab date.
The Maya also used the combination of the tzolkin date and the haab
date. This combination is a cycle of about 52 years called a *calendar
round*. If you type `g m p c', Emacs asks you for both a haab and a
tzolkin date and then moves point to the previous occurrence of that
combination. Use `g m n c' to move point to the next occurrence of a
combination. These commands signal an error if the haab/tzolkin date
combination you have typed is impossible.
Emacs uses strict completion (*note Strict Completion::.) whenever it
asks you to type a Mayan name, so you don't have to worry about
spelling.
The Diary
=========
The Emacs diary keeps track of appointments or other events on a
daily basis, in conjunction with the calendar. To use the diary
feature, you must first create a "diary file" containing a list of
events and their dates. Then Emacs can automatically pick out and
display the events for today, for the immediate future, or for any
specified date.
By default, Emacs uses `~/diary' as the diary file. This is the
same file that the `calendar' utility uses. A sample `~/diary' file is:
12/22/1988 Twentieth wedding anniversary!!
&1/1. Happy New Year!
10/22 Ruth's birthday.
* 21, *: Payday
Tuesday--weekly meeting with grad students at 10am
Supowit, Shen, Bitner, and Kapoor to attend.
1/13/89 Friday the thirteenth!!
&thu 4pm squash game with Lloyd.
mar 16 Dad's birthday
April 15, 1989 Income tax due.
&* 15 time cards due.
This example uses extra spaces to align the event descriptions of most
of the entries. Such formatting is purely a matter of taste.
Although you probably will start by creating a diary manually, Emacs
provides a number of commands to let you view, add, and change diary
entries.
Commands Displaying Diary Entries
---------------------------------
Once you have created a `~/diary' file, you can use the calendar to
view it. You can also view today's events outside of Calendar mode.
`d'
Display all diary entries for the selected date
(`view-diary-entries').
`Mouse-2 Diary'
Display all diary entries for the date you click on.
`s'
Display the entire diary file (`show-all-diary-entries').
`m'
Mark all visible dates that have diary entries
(`mark-diary-entries').
`u'
Unmark the calendar window (`calendar-unmark').
`M-x print-diary-entries'
Print hard copy of the diary display as it appears.
`M-x diary'
Display all diary entries for today's date.
`M-x diary-mail-entries'
Mail yourself email reminders about upcoming diary entries.
Displaying the diary entries with `d' shows in a separate window the
diary entries for the selected date in the calendar. The mode line of
the new window shows the date of the diary entries and any holidays
that fall on that date. If you specify a numeric argument with `d', it
shows all the diary entries for that many successive days. Thus, `2 d'
displays all the entries for the selected date and for the following
day.
Another way to display the diary entries for a date is to click
`Mouse-2' on the date, and then choose `Diary' from the menu that
appears.
To get a broader view of which days are mentioned in the diary, use
the `m' command. This displays the dates that have diary entries in a
different face (or places a `+' after these dates, if display with
multiple faces is not available). The command applies both to the
currently visible months and to other months that subsequently become
visible by scrolling. To turn marking off and erase the current marks,
type `u', which also turns off holiday marks (*note Holidays::.).
To see the full diary file, rather than just some of the entries, use
the `s' command.
Display of selected diary entries uses the selective display feature
to hide entries that don't apply.
The diary buffer as you see it is an illusion, so simply printing the
buffer does not print what you see on your screen. There is a special
command to print hard copy of the diary buffer *as it appears*; this
command is `M-x print-diary-entries'. It sends the data directly to
the printer. You can customize it like `lpr-region' (*note
Hardcopy::.).
The command `M-x diary' displays the diary entries for the current
date, independently of the calendar display, and optionally for the next
few days as well; the variable `number-of-diary-entries' specifies how
many days to include. *Note Customizing the Calendar and Diary:
(elisp)Calendar.
If you put `(diary)' in your `.emacs' file, this automatically
displays a window with the day's diary entries, when you enter Emacs.
The mode line of the displayed window shows the date and any holidays
that fall on that date.
Many users like to receive notice of events in their diary as email.
To send such mail to yourself, use the command `M-x
diary-mail-entries'. A prefix argument specifies how many days
(starting with today) to check; otherwise, the variable
`diary-mail-days' says how many days.
The Diary File
--------------
Your "diary file" is a file that records events associated with
particular dates. The name of the diary file is specified by the
variable `diary-file'; `~/diary' is the default. The `calendar'
utility program supports a subset of the format allowed by the Emacs
diary facilities, so you can use that utility to view the diary file,
with reasonable results aside from the entries it cannot understand.
Each entry in the diary file describes one event and consists of one
or more lines. An entry always begins with a date specification at the
left margin. The rest of the entry is simply text to describe the
event. If the entry has more than one line, then the lines after the
first must begin with whitespace to indicate they continue a previous
entry. Lines that do not begin with valid dates and do not continue a
preceding entry are ignored.
You can inhibit the marking of certain diary entries in the calendar
window; to do this, insert an ampersand (`&') at the beginning of the
entry, before the date. This has no effect on display of the entry in
the diary window; it affects only marks on dates in the calendar
window. Nonmarking entries are especially useful for generic entries
that would otherwise mark many different dates.
If the first line of a diary entry consists only of the date or day
name with no following blanks or punctuation, then the diary window
display doesn't include that line; only the continuation lines appear.
For example, this entry:
02/11/1989
Bill B. visits Princeton today
2pm Cognitive Studies Committee meeting
2:30-5:30 Liz at Lawrenceville
4:00pm Dentist appt
7:30pm Dinner at George's
8:00-10:00pm concert
appears in the diary window without the date line at the beginning.
This style of entry looks neater when you display just a single day's
entries, but can cause confusion if you ask for more than one day's
entries.
You can edit the diary entries as they appear in the window, but it
is important to remember that the buffer displayed contains the *entire*
diary file, with portions of it concealed from view. This means, for
instance, that the `C-f' (`forward-char') command can put point at what
appears to be the end of the line, but what is in reality the middle of
some concealed line.
*Be careful when editing the diary entries!* Inserting additional
lines or adding/deleting characters in the middle of a visible line
cannot cause problems, but editing at the end of a line may not do what
you expect. Deleting a line may delete other invisible entries that
follow it. Before editing the diary, it is best to display the entire
file with `s' (`show-all-diary-entries').
Date Formats
------------
Here are some sample diary entries, illustrating different ways of
formatting a date. The examples all show dates in American order
(month, day, year), but Calendar mode supports European order (day,
month, year) as an option.
4/20/93 Switch-over to new tabulation system
apr. 25 Start tabulating annual results
4/30 Results for April are due
*/25 Monthly cycle finishes
Friday Don't leave without backing up files
The first entry appears only once, on April 20, 1993. The second and
third appear every year on the specified dates, and the fourth uses a
wildcard (asterisk) for the month, so it appears on the 25th of every
month. The final entry appears every week on Friday.
You can use just numbers to express a date, as in `MONTH/DAY' or
`MONTH/DAY/YEAR'. This must be followed by a nondigit. In the date
itself, MONTH and DAY are numbers of one or two digits. The optional
YEAR is also a number, and may be abbreviated to the last two digits;
that is, you can use `11/12/1989' or `11/12/89'.
Dates can also have the form `MONTHNAME DAY' or `MONTHNAME DAY,
YEAR', where the month's name can be spelled in full or abbreviated to
three characters (with or without a period). Case is not significant.
A date may be "generic"; that is, partially unspecified. Then the
entry applies to all dates that match the specification. If the date
does not contain a year, it is generic and applies to any year.
Alternatively, MONTH, DAY, or YEAR can be a `*'; this matches any
month, day, or year, respectively. Thus, a diary entry `3/*/*' matches
any day in March of any year; so does `march *'.
If you prefer the European style of writing dates--in which the day
comes before the month--type `M-x european-calendar' while in the
calendar, or set the variable `european-calendar-style' to `t' *before*
using any calendar or diary command. This mode interprets all dates in
the diary in the European manner, and also uses European style for
displaying diary dates. (Note that there is no comma after the
MONTHNAME in the European style.) To go back to the (default) American
style of writing dates, type `M-x american-calendar'.
You can use the name of a day of the week as a generic date which
applies to any date falling on that day of the week. You can abbreviate
the day of the week to three letters (with or without a period) or spell
it in full; case is not significant.
Commands to Add to the Diary
----------------------------
While in the calendar, there are several commands to create diary
entries:
`i d'
Add a diary entry for the selected date (`insert-diary-entry').
`i w'
Add a diary entry for the selected day of the week
(`insert-weekly-diary-entry').
`i m'
Add a diary entry for the selected day of the month
(`insert-monthly-diary-entry').
`i y'
Add a diary entry for the selected day of the year
(`insert-yearly-diary-entry').
You can make a diary entry for a specific date by selecting that date
in the calendar window and typing the `i d' command. This command
displays the end of your diary file in another window and inserts the
date; you can then type the rest of the diary entry.
If you want to make a diary entry that applies to a specific day of
the week, select that day of the week (any occurrence will do) and type
`i w'. This inserts the day-of-week as a generic date; you can then
type the rest of the diary entry. You can make a monthly diary entry in
the same fashion. Select the day of the month, use the `i m' command,
and type rest of the entry. Similarly, you can insert a yearly diary
entry with the `i y' command.
All of the above commands make marking diary entries by default. To
make a nonmarking diary entry, give a numeric argument to the command.
For example, `C-u i w' makes a nonmarking weekly diary entry.
When you modify the diary file, be sure to save the file before
exiting Emacs.
Special Diary Entries
---------------------
In addition to entries based on calendar dates, the diary file can
contain "sexp entries" for regular events such as anniversaries. These
entries are based on Lisp expressions (sexps) that Emacs evaluates as
it scans the diary file. Instead of a date, a sexp entry contains `%%'
followed by a Lisp expression which must begin and end with
parentheses. The Lisp expression determines which dates the entry
applies to.
Calendar mode provides commands to insert certain commonly used sexp
entries:
`i a'
Add an anniversary diary entry for the selected date
(`insert-anniversary-diary-entry').
`i b'
Add a block diary entry for the current region
(`insert-block-diary-entry').
`i c'
Add a cyclic diary entry starting at the date
(`insert-cyclic-diary-entry').
If you want to make a diary entry that applies to the anniversary of
a specific date, move point to that date and use the `i a' command.
This displays the end of your diary file in another window and inserts
the anniversary description; you can then type the rest of the diary
entry. The entry looks like this:
%%(diary-anniversary 10 31 1948) Arthur's birthday
This entry applies to October 31 in any year after 1948; `10 31 1948'
specifies the date. (If you are using the European calendar style, the
month and day are interchanged.) The reason this expression requires a
beginning year is that advanced diary functions can use it to calculate
the number of elapsed years.
A "block" diary entry applies to a specified range of consecutive
dates. Here is a block diary entry that applies to all dates from June
24, 1990 through July 10, 1990:
%%(diary-block 6 24 1990 7 10 1990) Vacation
The `6 24 1990' indicates the starting date and the `7 10 1990'
indicates the stopping date. (Again, if you are using the European
calendar style, the month and day are interchanged.)
To insert a block entry, place point and the mark on the two dates
that begin and end the range, and type `i b'. This command displays
the end of your diary file in another window and inserts the block
description; you can then type the diary entry.
"Cyclic" diary entries repeat after a fixed interval of days. To
create one, select the starting date and use the `i c' command. The
command prompts for the length of interval, then inserts the entry,
which looks like this:
%%(diary-cyclic 50 3 1 1990) Renew medication
This entry applies to March 1, 1990 and every 50th day following; `3 1
1990' specifies the starting date. (If you are using the European
calendar style, the month and day are interchanged.)
All three of these commands make marking diary entries. To insert a
nonmarking entry, give a numeric argument to the command. For example,
`C-u i a' makes a nonmarking anniversary diary entry.
Marking sexp diary entries in the calendar is *extremely*
time-consuming, since every date visible in the calendar window must be
individually checked. So it's a good idea to make sexp diary entries
nonmarking (with `&') when possible.
Another sophisticated kind of sexp entry, a "floating" diary entry,
specifies a regularly occurring event by offsets specified in days,
weeks, and months. It is comparable to a crontab entry interpreted by
the `cron' utility. Here is a nonmarking, floating diary entry that
applies to the last Thursday in November:
&%%(diary-float 11 4 -1) American Thanksgiving
The 11 specifies November (the eleventh month), the 4 specifies Thursday
(the fourth day of the week, where Sunday is numbered zero), and the -1
specifies "last" (1 would mean "first," 2 would mean "second," -2 would
mean "second-to-last," and so on). The month can be a single month or
a list of months. Thus you could change the 11 above to `'(1 2 3)' and
have the entry apply to the last Thursday of January, February, and
March. If the month is `t', the entry applies to all months of the
year.
Most generally, sexp diary entries can perform arbitrary
computations to determine when they apply. *Note Sexp Diary Entries:
(elisp)Sexp Diary Entries.
Appointments
============
If you have a diary entry for an appointment, and that diary entry
begins with a recognizable time of day, Emacs can warn you, several
minutes beforehand, that that appointment is pending. Emacs alerts you
to the appointment by displaying a message in the mode line.
To enable appointment notification, you must enable the time display
feature of Emacs, `M-x display-time' (*note Mode Line::.). You must
also add the function `appt-make-list' to the `diary-hook', like this:
(add-hook 'diary-hook 'appt-make-list)
Adding this text to your `.emacs' file does the whole job:
(display-time)
(add-hook 'diary-hook 'appt-make-list)
(diary 0)
With these preparations done, when you display the diary (either with
the `d' command in the calendar window or with the `M-x diary'
command), it sets up an appointment list of all the diary entries found
with recognizable times of day, and reminds you just before each of
them.
For example, suppose the diary file contains these lines:
Monday
9:30am Coffee break
12:00pm Lunch
Then on Mondays, after you have displayed the diary, you will be
reminded at 9:20am about your coffee break and at 11:50am about lunch.
You can write times in am/pm style (with `12:00am' standing for
midnight and `12:00pm' standing for noon), or 24-hour European/military
style. You need not be consistent; your diary file can have a mixture
of the two styles.
Emacs updates the appointments list automatically just after
midnight. This also displays the next day's diary entries in the diary
buffer, unless you set `appt-display-diary' to `nil'.
You can also use the appointment notification facility like an alarm
clock. The command `M-x appt-add' adds entries to the appointment list
without affecting your diary file. You delete entries from the
appointment list with `M-x appt-delete'.
You can turn off the appointment notification feature at any time by
setting `appt-issue-message' to `nil'.
Daylight Savings Time
=====================
Emacs understands the difference between standard time and daylight
savings time--the times given for sunrise, sunset, solstices,
equinoxes, and the phases of the moon take that into account. The rules
for daylight savings time vary from place to place and have also varied
historically from year to year. To do the job properly, Emacs needs to
know which rules to use.
Some operating systems keep track of the rules that apply to the
place where you are; on these systems, Emacs gets the information it
needs from the system automatically. If some or all of this
information is missing, Emacs fills in the gaps with the rules
currently used in Cambridge, Massachusetts. If the resulting rules are
not what you want, you can tell Emacs the rules to use by setting
certain variables: `calendar-daylight-savings-starts' and
`calendar-daylight-savings-ends'.
These values should be Lisp expressions that refer to the variable
`year', and evaluate to the Gregorian date on which daylight savings
time starts or (respectively) ends, in the form of a list `(MONTH DAY
YEAR)'. The values should be `nil' if your area does not use daylight
savings time.
Emacs uses these expressions to determine the starting date of
daylight savings time for the holiday list and for correcting times of
day in the solar and lunar calculations.
The values for Cambridge, Massachusetts are as follows:
(calendar-nth-named-day 1 0 4 year)
(calendar-nth-named-day -1 0 10 year)
That is, the first 0th day (Sunday) of the fourth month (April) in the
year specified by `year', and the last Sunday of the tenth month
(October) of that year. If daylight savings time were changed to start
on October 1, you would set `calendar-daylight-savings-starts' to this:
(list 10 1 year)
If there is no daylight savings time at your location, or if you want
all times in standard time, set `calendar-daylight-savings-starts' and
`calendar-daylight-savings-ends' to `nil'.
The variable `calendar-daylight-time-offset' specifies the
difference between daylight savings time and standard time, measured in
minutes. The value for Cambridge, Massachusetts is 60.
The two variables `calendar-daylight-savings-starts-time' and
`calendar-daylight-savings-ends-time' specify the number of minutes
after midnight local time when the transition to and from daylight
savings time should occur. For Cambridge, Massachusetts both variables'
values are 120.
Gnus
====
Gnus is an Emacs package primarily designed for reading and posting
Usenet news. It can also be used to read and respond to messages from a
number of other sources--mail, remote directories, digests, and so on.
Here we introduce Gnus and describe several basic features. For
full details, see *Note Gnus: (gnus)Top.
To start Gnus, type `M-x gnus <RET>'.
Gnus Buffers
------------
As opposed to most normal Emacs packages, Gnus uses a number of
different buffers to display information and to receive commands. The
three buffers users spend most of their time in are the "group buffer",
the "summary buffer" and the "article buffer".
The "group buffer" contains a list of groups. This is the first
buffer Gnus displays when it starts up. It normally displays only the
groups to which you subscribe and that contain unread articles. Use
this buffer to select a specific group.
The "summary buffer" lists one line for each article in a single
group. By default, the author, the subject and the line number are
displayed for each article, but this is customizable, like most aspects
of Gnus display. The summary buffer is created when you select a group
in the group buffer, and is killed when you exit the group. Use this
buffer to select an article.
The "article buffer" displays the article. In normal Gnus usage,
you don't select this buffer--all useful article-oriented commands work
in the summary buffer. But you can select the article buffer, and
execute all Gnus commands from that buffer, if you want to.
When Gnus Starts Up
-------------------
At startup, Gnus reads your `.newsrc' news initialization file and
attempts to communicate with the local news server, which is a
repository of news articles. The news server need not be the same
computer you are logged in on.
If you start Gnus and connect to the server, but do not see any
newsgroups listed in the group buffer, type `L' or `A k' to get a
listing of all the groups. Then type `u' to toggle subscription to
groups.
The first time you start Gnus, Gnus subscribes you to a few selected
groups. All other groups start out as "killed groups" for you; you can
list them with `A k'. All new groups that subsequently come to exist
at the news server become "zombie groups" for you; type `A z' to list
them. You can subscribe to a group shown in these lists using the `u'
command.
When you quit Gnus with `q', it automatically records in your
`.newsrc' and `.newsrc.eld' initialization files the subscribed or
unsubscribed status of all groups. You should normally not edit these
files manually, but you may if you know how.
Summary of Gnus Commands
------------------------
Reading news is a two step process:
1. Choose a group in the group buffer.
2. Select articles from the summary buffer. Each article selected is
displayed in the article buffer in a large window, below the
summary buffer in its small window.
Each Gnus buffer has its own special commands; however, the meanings
of any given key in the various Gnus buffers are usually analogous, even
if not identical. Here are commands for the group and summary buffers:
`q'
In the group buffer, update your `.newsrc' initialization file and
quit Gnus.
In the summary buffer, exit the current group and return to the
group buffer. Thus, typing `q' twice quits Gnus.
`L'
In the group buffer, list all the groups available on your news
server (except those you have killed). This may be a long list!
`l'
In the group buffer, list only the groups to which you subscribe
and which contain unread articles.
`u'
In the group buffer, unsubscribe from (or subscribe to) the group
listed in the line that point is on. When you quit Gnus by typing
`q', Gnus lists in your `.newsrc' file which groups you have
subscribed to. The next time you start Gnus, you won't see this
group, because Gnus normally displays only subscribed-to groups.
`C-k'
In the group buffer, "kill" the current line's group--don't even
list it in `.newsrc' from now on. This affects future Gnus
sessions as well as the present session.
When you quit Gnus by typing `q', Gnus writes information in the
file `.newsrc' describing all newsgroups except those you have
"killed."
`<SPC>'
In the group buffer, select the group on the line under the cursor
and display the first unread article in that group.
In the summary buffer,
* Select the article on the line under the cursor if none is
selected.
* Scroll the text of the selected article (if there is one).
* Select the next unread article if at the end of the current
article.
Thus, you can move through all the articles by repeatedly typing
<SPC>.
`<DEL>'
In the group buffer, move point to the previous group containing
unread articles.
In the summary buffer, scroll the text of the article backwards.
`n'
Move point to the next unread group, or select the next unread
article.
`p'
Move point to the previous unread group, or select the previous
unread article.
`C-n'
`C-p'
Move point to the next or previous item, even if it is marked as
read. This does not select the article or group on that line.
`s'
In the summary buffer, do an incremental search of the current
text in the article buffer, just as if you switched to the article
buffer and typed `C-s'.
`M-s REGEXP <RET>'
In the summary buffer, search forward for articles containing a
match for REGEXP.
Running Shell Commands from Emacs
=================================
Emacs has commands for passing single command lines to inferior shell
processes; it can also run a shell interactively with input and output
to an Emacs buffer named `*shell*'.
`M-! CMD <RET>'
Run the shell command line CMD and display the output
(`shell-command').
`M-| CMD <RET>'
Run the shell command line CMD with region contents as input;
optionally replace the region with the output
(`shell-command-on-region').
`M-x shell'
Run a subshell with input and output through an Emacs buffer. You
can then give commands interactively.
Single Shell Commands
---------------------
`M-!' (`shell-command') reads a line of text using the minibuffer
and executes it as a shell command in a subshell made just for that
command. Standard input for the command comes from the null device.
If the shell command produces any output, the output goes into an Emacs
buffer named `*Shell Command Output*', which is displayed in another
window but not selected. A numeric argument, as in `M-1 M-!', directs
this command to insert any output into the current buffer. In that
case, point is left before the output and the mark is set after the
output.
If the shell command line ends in `&', it runs asynchronously. For
a synchronous shell command, `shell-command' returns the command's exit
status (0 means success), when it is called from a Lisp program.
`M-|' (`shell-command-on-region') is like `M-!' but passes the
contents of the region as the standard input to the shell command,
instead of no input. If a numeric argument is used, meaning insert the
output in the current buffer, then the old region is deleted first and
the output replaces it as the contents of the region. It returns the
command's exit status when it is called from a Lisp program.
Both `M-!' and `M-|' use `shell-file-name' to specify the shell to
use. This variable is initialized based on your `SHELL' environment
variable when Emacs is started. If the file name does not specify a
directory, the directories in the list `exec-path' are searched; this
list is initialized based on the environment variable `PATH' when Emacs
is started. Your `.emacs' file can override either or both of these
default initializations.
Both `M-!' and `M-|' wait for the shell command to complete. To
stop waiting, type `C-g' to quit; that terminates the shell command
with the signal `SIGINT'--the same signal that `C-c' normally generates
in the shell. Emacs waits until the command actually terminates. If
the shell command doesn't stop (because it ignores the `SIGINT'
signal), type `C-g' again; this sends the command a `SIGKILL' signal
which is impossible to ignore.
To specify a coding system for `M-!' or `M-|', use the command `C-x
<RET> c' immediately beforehand. *Note Specify Coding::.
Error output from the command is normally intermixed with the regular
output. If you set the variable `shell-command-default-error-buffer'
to a string, which is a buffer name, error output is inserted before
point in the buffer of that name.
Interactive Inferior Shell
--------------------------
To run a subshell interactively, putting its typescript in an Emacs
buffer, use `M-x shell'. This creates (or reuses) a buffer named
`*shell*' and runs a subshell with input coming from and output going
to that buffer. That is to say, any "terminal output" from the subshell
goes into the buffer, advancing point, and any "terminal input" for the
subshell comes from text in the buffer. To give input to the subshell,
go to the end of the buffer and type the input, terminated by <RET>.
Emacs does not wait for the subshell to do anything. You can switch
windows or buffers and edit them while the shell is waiting, or while
it is running a command. Output from the subshell waits until Emacs
has time to process it; this happens whenever Emacs is waiting for
keyboard input or for time to elapse.
To make multiple subshells, rename the buffer `*shell*' to something
different using `M-x rename-uniquely'. Then type `M-x shell' again to
create a new buffer `*shell*' with its own subshell. If you rename
this buffer as well, you can create a third one, and so on. All the
subshells run independently and in parallel.
The file name used to load the subshell is the value of the variable
`explicit-shell-file-name', if that is non-`nil'. Otherwise, the
environment variable `ESHELL' is used, or the environment variable
`SHELL' if there is no `ESHELL'. If the file name specified is
relative, the directories in the list `exec-path' are searched; this
list is initialized based on the environment variable `PATH' when Emacs
is started. Your `.emacs' file can override either or both of these
default initializations.
To specify a coding system for the shell, you can use the command
`C-x <RET> c' immediately before `M-x shell'. You can also specify a
coding system after starting the shell by using `C-x <RET> p' in the
shell buffer. *Note Specify Coding::.
As soon as the subshell is started, it is sent as input the contents
of the file `~/.emacs_SHELLNAME', if that file exists, where SHELLNAME
is the name of the file that the shell was loaded from. For example,
if you use bash, the file sent to it is `~/.emacs_bash'.
`cd', `pushd' and `popd' commands given to the inferior shell are
watched by Emacs so it can keep the `*shell*' buffer's default
directory the same as the shell's working directory. These commands
are recognized syntactically by examining lines of input that are sent.
If you use aliases for these commands, you can tell Emacs to recognize
them also. For example, if the value of the variable
`shell-pushd-regexp' matches the beginning of a shell command line,
that line is regarded as a `pushd' command. Change this variable when
you add aliases for `pushd'. Likewise, `shell-popd-regexp' and
`shell-cd-regexp' are used to recognize commands with the meaning of
`popd' and `cd'. These commands are recognized only at the beginning
of a shell command line.
If Emacs gets an error while trying to handle what it believes is a
`cd', `pushd' or `popd' command, it runs the hook
`shell-set-directory-error-hook' (*note Hooks::.).
If Emacs does not properly track changes in the current directory of
the subshell, use the command `M-x dirs' to ask the shell what its
current directory is. This command works for shells that support the
most common command syntax; it may not work for unusual shells.
You can also use `M-x dirtrack-mode' to enable (or disable) an
alternative and more aggressive method of tracking changes in the
current directory.
Emacs defines the environment variable `EMACS' in the subshell, with
value `t'. A shell script can check this variable to determine whether
it has been run from an Emacs subshell.
Shell Mode
----------
Shell buffers use Shell mode, which defines several special keys
attached to the `C-c' prefix. They are chosen to resemble the usual
editing and job control characters present in shells that are not under
Emacs, except that you must type `C-c' first. Here is a complete list
of the special key bindings of Shell mode:
`<RET>'
At end of buffer send line as input; otherwise, copy current line
to end of buffer and send it (`comint-send-input'). When a line is
copied, any text at the beginning of the line that matches the
variable `shell-prompt-pattern' is left out; this variable's value
should be a regexp string that matches the prompts that your shell
uses.
`<TAB>'
Complete the command name or file name before point in the shell
buffer (`comint-dynamic-complete'). <TAB> also completes history
references (*note History References::.) and environment variable
names.
The variable `shell-completion-fignore' specifies a list of file
name extensions to ignore in Shell mode completion. The default
setting ignores file names ending in `~', `#' or `%'. Other
related Comint modes use the variable `comint-completion-fignore'
instead.
`M-?'
Display temporarily a list of the possible completions of the file
name before point in the shell buffer
(`comint-dynamic-list-filename-completions').
`C-d'
Either delete a character or send EOF
(`comint-delchar-or-maybe-eof'). Typed at the end of the shell
buffer, `C-d' sends EOF to the subshell. Typed at any other
position in the buffer, `C-d' deletes a character as usual.
`C-c C-a'
Move to the beginning of the line, but after the prompt if any
(`comint-bol'). If you repeat this command twice in a row, the
second time it moves back to the process mark, which is the
beginning of the input that you have not yet sent to the subshell.
(Normally that is the same place--the end of the prompt on this
line--but after `C-c <SPC>' the process mark may be in a previous
line.)
`C-c <SPC>'
Accumulate multiple lines of input, then send them together. This
command inserts a newline before point, but does not send the
preceding text as input to the subshell--at least, not yet. Both
lines, the one before this newline and the one after, will be sent
together (along with the newline that separates them), when you
type <RET>.
`C-c C-u'
Kill all text pending at end of buffer to be sent as input
(`comint-kill-input').
`C-c C-w'
Kill a word before point (`backward-kill-word').
`C-c C-c'
Interrupt the shell or its current subjob if any
(`comint-interrupt-subjob'). This command also kills any shell
input pending in the shell buffer and not yet sent.
`C-c C-z'
Stop the shell or its current subjob if any (`comint-stop-subjob').
This command also kills any shell input pending in the shell
buffer and not yet sent.
`C-c C-\'
Send quit signal to the shell or its current subjob if any
(`comint-quit-subjob'). This command also kills any shell input
pending in the shell buffer and not yet sent.
`C-c C-o'
Kill the last batch of output from a shell command
(`comint-kill-output'). This is useful if a shell command spews
out lots of output that just gets in the way.
`C-c C-r'
`C-M-l'
Scroll to display the beginning of the last batch of output at the
top of the window; also move the cursor there
(`comint-show-output').
`C-c C-e'
Scroll to put the end of the buffer at the bottom of the window
(`comint-show-maximum-output').
`C-c C-f'
Move forward across one shell command, but not beyond the current
line (`shell-forward-command'). The variable
`shell-command-regexp' specifies how to recognize the end of a
command.
`C-c C-b'
Move backward across one shell command, but not beyond the current
line (`shell-backward-command').
`C-c C-l'
Display the buffer's history of shell commands in another window
(`comint-dynamic-list-input-ring').
`M-x dirs'
Ask the shell what its current directory is, so that Emacs can
agree with the shell.
`M-x send-invisible <RET> TEXT <RET>'
Send TEXT as input to the shell, after reading it without echoing.
This is useful when a shell command runs a program that asks for
a password.
Alternatively, you can arrange for Emacs to notice password prompts
and turn off echoing for them, as follows:
(add-hook 'comint-output-filter-functions
'comint-watch-for-password-prompt)
`M-x comint-continue-subjob'
Continue the shell process. This is useful if you accidentally
suspend the shell process.(1)
`M-x comint-strip-ctrl-m'
Discard all control-M characters from the current group of shell
output. The most convenient way to use this command is to make it
run automatically when you get output from the subshell. To do
that, evaluate this Lisp expression:
(add-hook 'comint-output-filter-functions
'comint-strip-ctrl-m)
`M-x comint-truncate-buffer'
This command truncates the shell buffer to a certain maximum
number of lines, specified by the variable
`comint-buffer-maximum-size'. Here's how to do this automatically
each time you get output from the subshell:
(add-hook 'comint-output-filter-functions
'comint-truncate-buffer)
Shell mode also customizes the paragraph commands so that only shell
prompts start new paragraphs. Thus, a paragraph consists of an input
command plus the output that follows it in the buffer.
Shell mode is a derivative of Comint mode, a general-purpose mode for
communicating with interactive subprocesses. Most of the features of
Shell mode actually come from Comint mode, as you can see from the
command names listed above. The special features of Shell mode in
particular include the choice of regular expression for detecting
prompts, the directory tracking feature, and a few user commands.
Other Emacs features that use variants of Comint mode include GUD
(*note Debuggers::.) and `M-x run-lisp' (*note External Lisp::.).
You can use `M-x comint-run' to execute any program of your choice
in a subprocess using unmodified Comint mode--without the
specializations of Shell mode.
---------- Footnotes ----------
(1) You should not suspend the shell process. Suspending a subjob
of the shell is a completely different matter--that is normal practice,
but you must use the shell to continue the subjob; this command won't
do it.
Shell Command History
---------------------
Shell buffers support three ways of repeating earlier commands. You
can use the same keys used in the minibuffer; these work much as they do
in the minibuffer, inserting text from prior commands while point
remains always at the end of the buffer. You can move through the
buffer to previous inputs in their original place, then resubmit them or
copy them to the end. Or you can use a `!'-style history reference.
Shell History Ring
..................
`M-p'
Fetch the next earlier old shell command.
`M-n'
Fetch the next later old shell command.
`M-r REGEXP <RET>'
`M-s REGEXP <RET>'
Search backwards or forwards for old shell commands that match
REGEXP.
`C-c C-x (Shell mode)'
Fetch the next subsequent command from the history.
Shell buffers provide a history of previously entered shell
commands. To reuse shell commands from the history, use the editing
commands `M-p', `M-n', `M-r' and `M-s'. These work just like the
minibuffer history commands except that they operate on the text at the
end of the shell buffer, where you would normally insert text to send
to the shell.
`M-p' fetches an earlier shell command to the end of the shell
buffer. Successive use of `M-p' fetches successively earlier shell
commands, each replacing any text that was already present as potential
shell input. `M-n' does likewise except that it finds successively
more recent shell commands from the buffer.
The history search commands `M-r' and `M-s' read a regular
expression and search through the history for a matching command. Aside
from the choice of which command to fetch, they work just like `M-p'
and `M-r'. If you enter an empty regexp, these commands reuse the same
regexp used last time.
When you find the previous input you want, you can resubmit it by
typing <RET>, or you can edit it first and then resubmit it if you wish.
Often it is useful to reexecute several successive shell commands
that were previously executed in sequence. To do this, first find and
reexecute the first command of the sequence. Then type `C-c C-x'; that
will fetch the following command--the one that follows the command you
just repeated. Then type <RET> to reexecute this command. You can
reexecute several successive commands by typing `C-c C-x <RET>' over
and over.
These commands get the text of previous shell commands from a special
history list, not from the shell buffer itself. Thus, editing the shell
buffer, or even killing large parts of it, does not affect the history
that these commands access.
Some shells store their command histories in files so that you can
refer to previous commands from previous shell sessions. Emacs reads
the command history file for your chosen shell, to initialize its own
command history. The file name is `~/.bash_history' for bash,
`~/.sh_history' for ksh, and `~/.history' for other shells.
Shell History Copying
.....................
`C-c C-p'
Move point to the previous prompt (`comint-previous-prompt').
`C-c C-n'
Move point to the following prompt (`comint-next-prompt').
`C-c <RET>'
Copy the input command which point is in, inserting the copy at
the end of the buffer (`comint-copy-old-input'). This is useful
if you move point back to a previous command. After you copy the
command, you can submit the copy as input with <RET>. If you
wish, you can edit the copy before resubmitting it.
Moving to a previous input and then copying it with `C-c <RET>'
produces the same results--the same buffer contents--that you would get
by using `M-p' enough times to fetch that previous input from the
history list. However, `C-c <RET>' copies the text from the buffer,
which can be different from what is in the history list if you edit the
input text in the buffer after it has been sent.
Shell History References
........................
Various shells including csh and bash support "history references"
that begin with `!' and `^'. Shell mode can understand these
constructs and perform the history substitution for you. If you insert
a history reference and type <TAB>, this searches the input history for
a matching command, performs substitution if necessary, and places the
result in the buffer in place of the history reference. For example,
you can fetch the most recent command beginning with `mv' with `! m v
<TAB>'. You can edit the command if you wish, and then resubmit the
command to the shell by typing <RET>.
History references take effect only following a shell prompt. The
variable `shell-prompt-pattern' specifies how to recognize a shell
prompt. Comint modes in general use the variable
`comint-prompt-regexp' to specify how to find a prompt; Shell mode uses
`shell-prompt-pattern' to set up the local value of
`comint-prompt-regexp'.
Shell mode can optionally expand history references in the buffer
when you send them to the shell. To request this, set the variable
`comint-input-autoexpand' to `input'.
You can make <SPC> perform history expansion by binding <SPC> to the
command `comint-magic-space'.
Shell Mode Options
------------------
If the variable `comint-scroll-to-bottom-on-input' is non-`nil',
insertion and yank commands scroll the selected window to the bottom
before inserting.
If `comint-scroll-show-maximum-output' is non-`nil', then scrolling
due to arrival of output tries to place the last line of text at the
bottom line of the window, so as to show as much useful text as
possible. (This mimics the scrolling behavior of many terminals.) The
default is `nil'.
By setting `comint-scroll-to-bottom-on-output', you can opt for
having point jump to the end of the buffer whenever output arrives--no
matter where in the buffer point was before. If the value is `this',
point jumps in the selected window. If the value is `all', point jumps
in each window that shows the comint buffer. If the value is `other',
point jumps in all nonselected windows that show the current buffer.
The default value is `nil', which means point does not jump to the end.
The variable `comint-input-ignoredups' controls whether successive
identical inputs are stored in the input history. A non-`nil' value
means to omit an input that is the same as the previous input. The
default is `nil', which means to store each input even if it is equal
to the previous input.
Three variables customize file name completion. The variable
`comint-completion-addsuffix' controls whether completion inserts a
space or a slash to indicate a fully completed file or directory name
(non-`nil' means do insert a space or slash).
`comint-completion-recexact', if non-`nil', directs <TAB> to choose the
shortest possible completion if the usual Emacs completion algorithm
cannot add even a single character. `comint-completion-autolist', if
non-`nil', says to list all the possible completions whenever
completion is not exact.
The command `comint-dynamic-complete-variable' does variable-name
completion using the environment variables as set within Emacs. The
variables controlling file name completion apply to variable-name
completion too. This command is normally available through the menu
bar.
Command completion normally considers only executable files. If you
set `shell-command-execonly' to `nil', it considers nonexecutable files
as well.
You can configure the behavior of `pushd'. Variables control
whether `pushd' behaves like `cd' if no argument is given
(`shell-pushd-tohome'), pop rather than rotate with a numeric argument
(`shell-pushd-dextract'), and only add directories to the directory
stack if they are not already on it (`shell-pushd-dunique'). The
values you choose should match the underlying shell, of course.
Remote Host Shell
-----------------
Emacs provides two commands for logging in to another computer and
communicating with it through an Emacs buffer.
`M-x telnet <RET> HOSTNAME <RET>'
Set up a Telnet connection to the computer named HOSTNAME.
`M-x rlogin <RET> HOSTNAME <RET>'
Set up an Rlogin connection to the computer named HOSTNAME.
Use `M-x telnet' to set up a Telnet connection to another computer.
(Telnet is the standard Internet protocol for remote login.) It reads
the host name of the other computer as an argument with the minibuffer.
Once the connection is established, talking to the other computer
works like talking to a subshell: you can edit input with the usual
Emacs commands, and send it a line at a time by typing <RET>. The
output is inserted in the Telnet buffer interspersed with the input.
Use `M-x rlogin' to set up an Rlogin connection. Rlogin is another
remote login communication protocol, essentially much like the Telnet
protocol but incompatible with it, and supported only by certain
systems. Rlogin's advantages are that you can arrange not to have to
give your user name and password when communicating between two machines
you frequently use, and that you can make an 8-bit-clean connection.
(To do that in Emacs, set `rlogin-explicit-args' to `("-8")' before you
run Rlogin.)
`M-x rlogin' sets up the default file directory of the Emacs buffer
to access the remote host via FTP (*note File Names::.), and it tracks
the shell commands that change the current directory, just like Shell
mode.
There are two ways of doing directory tracking in an Rlogin
buffer--either with remote directory names `/HOST:DIR/' or with local
names (that works if the "remote" machine shares file systems with your
machine of origin). You can use the command
`rlogin-directory-tracking-mode' to switch modes. No argument means
use remote directory names, a positive argument means use local names,
and a negative argument means turn off directory tracking.
Using Emacs as a Server
=======================
Various programs such as `mail' can invoke your choice of editor to
edit a particular piece of text, such as a message that you are
sending. By convention, most of these programs use the environment
variable `EDITOR' to specify which editor to run. If you set `EDITOR'
to `emacs', they invoke Emacs--but in an inconvenient fashion, by
starting a new, separate Emacs process. This is inconvenient because
it takes time and because the new Emacs process doesn't share the
buffers in the existing Emacs process.
You can arrange to use your existing Emacs process as the editor for
programs like `mail' by using the Emacs client and Emacs server
programs. Here is how.
First, the preparation. Within Emacs, call the function
`server-start'. (Your `.emacs' file can do this automatically if you
add the expression `(server-start)' to it.) Then, outside Emacs, set
the `EDITOR' environment variable to `emacsclient'. (Note that some
programs use a different environment variable; for example, to make TeX
use `emacsclient', you should set the `TEXEDIT' environment variable to
`emacsclient +%d %s'.)
Then, whenever any program invokes your specified `EDITOR' program,
the effect is to send a message to your principal Emacs telling it to
visit a file. (That's what the program `emacsclient' does.) Emacs
displays the buffer immediately and you can immediately begin editing
it.
When you've finished editing that buffer, type `C-x #'
(`server-edit'). This saves the file and sends a message back to the
`emacsclient' program telling it to exit. The programs that use
`EDITOR' wait for the "editor" (actually, `emacsclient') to exit. `C-x
#' also checks for other pending external requests to edit various
files, and selects the next such file.
You can switch to a server buffer manually if you wish; you don't
have to arrive at it with `C-x #'. But `C-x #' is the only way to say
that you are "finished" with one.
If you set the variable `server-window' to a window or a frame, `C-x
#' displays the server buffer in that window or in that frame.
While `mail' or another application is waiting for `emacsclient' to
finish, `emacsclient' does not read terminal input. So the terminal
that `mail' was using is effectively blocked for the duration. In
order to edit with your principal Emacs, you need to be able to use it
without using that terminal. There are two ways to do this:
* Using a window system, run `mail' and the principal Emacs in two
separate windows. While `mail' is waiting for `emacsclient', the
window where it was running is blocked, but you can use Emacs by
switching windows.
* Use Shell mode in Emacs to run the other program such as `mail';
then, `emacsclient' blocks only the subshell under Emacs, and you
can still use Emacs to edit the file.
Some programs write temporary files for you to edit. After you edit
the temporary file, the program reads it back and deletes it. If the
Emacs server is later asked to edit the same file name, it should assume
this has nothing to do with the previous occasion for that file name.
The server accomplishes this by killing the temporary file's buffer when
you finish with the file. Use the variable `server-temp-file-regexp'
to specify which files are temporary in this sense; its value should be
a regular expression that matches file names that are temporary.
If you run `emacsclient' with the option `--no-wait', it returns
immediately without waiting for you to "finish" the buffer in Emacs.
Hardcopy Output
===============
The Emacs commands for making hardcopy let you print either an entire
buffer or just part of one, either with or without page headers. See
also the hardcopy commands of Dired (*note Misc File Ops::.) and the
diary (*note Diary Commands::.).
`M-x print-buffer'
Print hardcopy of current buffer with page headings containing the
file name and page number.
`M-x lpr-buffer'
Print hardcopy of current buffer without page headings.
`M-x print-region'
Like `print-buffer' but print only the current region.
`M-x lpr-region'
Like `lpr-buffer' but print only the current region.
The hardcopy commands (aside from the Postscript commands) pass extra
switches to the `lpr' program based on the value of the variable
`lpr-switches'. Its value should be a list of strings, each string an
option starting with `-'. For example, to specify a line width of 80
columns for all the printing you do in Emacs, set `lpr-switches' like
this:
(setq lpr-switches '("-w80"))
You can specify the printer to use by setting the variable
`printer-name'.
The variable `lpr-command' specifies the name of the printer program
to run; the default value depends on your operating system type. On
most systems, the default is `"lpr"'. The variable
`lpr-headers-switches' similarly specifies the extra switches to use to
make page headers. The variable `lpr-add-switches' controls whether to
supply `-T' and `-J' options (suitable for `lpr') to the printer
program: `nil' means don't add them. `lpr-add-switches' should be
`nil' if your printer program is not compatible with `lpr'.
Postscript Hardcopy
===================
These commands convert buffer contents to Postscript, either
printing it or leaving it in another Emacs buffer.
`M-x ps-print-buffer'
Print hardcopy of the current buffer in Postscript form.
`M-x ps-print-region'
Print hardcopy of the current region in Postscript form.
`M-x ps-print-buffer-with-faces'
Print hardcopy of the current buffer in Postscript form, showing
the faces used in the text by means of Postscript features.
`M-x ps-print-region-with-faces'
Print hardcopy of the current region in Postscript form, showing
the faces used in the text.
`M-x ps-spool-buffer'
Generate Postscript for the current buffer text.
`M-x ps-spool-region'
Generate Postscript for the current region.
`M-x ps-spool-buffer-with-faces'
Generate Postscript for the current buffer, showing the faces used.
`M-x ps-spool-region-with-faces'
Generate Postscript for the current region, showing the faces used.
The Postscript commands, `ps-print-buffer' and `ps-print-region',
print buffer contents in Postscript form. One command prints the
entire buffer; the other, just the region. The corresponding
`-with-faces' commands, `ps-print-buffer-with-faces' and
`ps-print-region-with-faces', use Postscript features to show the faces
(fonts and colors) in the text properties of the text being printed.
If you are using a color display, you can print a buffer of program
code with color highlighting by turning on Font-Lock mode in that
buffer, and using `ps-print-buffer-with-faces'.
The commands whose names have `spool' instead of `print' generate
the Postscript output in an Emacs buffer instead of sending it to the
printer.
The following section describes variables for customizing these
commands.
Variables for Postscript Hardcopy
=================================
All the Postscript hardcopy commands use the variables
`ps-lpr-command' and `ps-lpr-switches' to specify how to print the
output. `ps-lpr-command' specifies the command name to run,
`ps-lpr-switches' specifies command line options to use, and
`ps-printer-name' specifies the printer. If you don't set the first
two variables yourself, they take their initial values from
`lpr-command' and `lpr-switches'. If `ps-printer-name' is `nil',
`printer-name' is used.
The variable `ps-print-header' controls whether these commands add
header lines to each page--set it to `nil' to turn headers off. You
can turn off color processing by setting `ps-print-color-p' to `nil'.
The variable `ps-paper-type' specifies which size of paper to format
for; legitimate values include `a4', `a3', `a4small', `b4', `b5',
`executive', `ledger', `legal', `letter', `letter-small', `statement',
`tabloid'. The default is `letter'. You can define additional paper
sizes by changing the variable `ps-page-dimensions-database'.
The variable `ps-landscape-mode' specifies the orientation of
printing on the page. The default is `nil', which stands for
"portrait" mode. Any non-`nil' value specifies "landscape" mode.
The variable `ps-number-of-columns' specifies the number of columns;
it takes effect in both landscape and portrait mode. The default is 1.
The variable `ps-font-family' specifies which font family to use for
printing ordinary text. Legitimate values include `Courier',
`Helvetica', `NewCenturySchlbk', `Palatino' and `Times'. The variable
`ps-font-size' specifies the size of the font for ordinary text. It
defaults to 8.5 points.
Many other customization variables for these commands are defined and
described in the Lisp file `ps-print.el'.
Sorting Text
============
Emacs provides several commands for sorting text in the buffer. All
operate on the contents of the region (the text between point and the
mark). They divide the text of the region into many "sort records",
identify a "sort key" for each record, and then reorder the records
into the order determined by the sort keys. The records are ordered so
that their keys are in alphabetical order, or, for numeric sorting, in
numeric order. In alphabetic sorting, all upper-case letters `A'
through `Z' come before lower-case `a', in accord with the ASCII
character sequence.
The various sort commands differ in how they divide the text into
sort records and in which part of each record is used as the sort key.
Most of the commands make each line a separate sort record, but some
commands use paragraphs or pages as sort records. Most of the sort
commands use each entire sort record as its own sort key, but some use
only a portion of the record as the sort key.
`M-x sort-lines'
Divide the region into lines, and sort by comparing the entire
text of a line. A numeric argument means sort into descending
order.
`M-x sort-paragraphs'
Divide the region into paragraphs, and sort by comparing the entire
text of a paragraph (except for leading blank lines). A numeric
argument means sort into descending order.
`M-x sort-pages'
Divide the region into pages, and sort by comparing the entire
text of a page (except for leading blank lines). A numeric
argument means sort into descending order.
`M-x sort-fields'
Divide the region into lines, and sort by comparing the contents of
one field in each line. Fields are defined as separated by
whitespace, so the first run of consecutive non-whitespace
characters in a line constitutes field 1, the second such run
constitutes field 2, etc.
Specify which field to sort by with a numeric argument: 1 to sort
by field 1, etc. A negative argument means count fields from the
right instead of from the left; thus, minus 1 means sort by the
last field. If several lines have identical contents in the field
being sorted, they keep same relative order that they had in the
original buffer.
`M-x sort-numeric-fields'
Like `M-x sort-fields' except the specified field is converted to
an integer for each line, and the numbers are compared. `10'
comes before `2' when considered as text, but after it when
considered as a number.
`M-x sort-columns'
Like `M-x sort-fields' except that the text within each line used
for comparison comes from a fixed range of columns. See below for
an explanation.
`M-x reverse-region'
Reverse the order of the lines in the region. This is useful for
sorting into descending order by fields or columns, since those
sort commands do not have a feature for doing that.
For example, if the buffer contains this:
On systems where clash detection (locking of files being edited) is
implemented, Emacs also checks the first time you modify a buffer
whether the file has changed on disk since it was last visited or
saved. If it has, you are asked to confirm that you want to change
the buffer.
applying `M-x sort-lines' to the entire buffer produces this:
On systems where clash detection (locking of files being edited) is
implemented, Emacs also checks the first time you modify a buffer
saved. If it has, you are asked to confirm that you want to change
the buffer.
whether the file has changed on disk since it was last visited or
where the upper-case `O' sorts before all lower-case letters. If you
use `C-u 2 M-x sort-fields' instead, you get this:
implemented, Emacs also checks the first time you modify a buffer
saved. If it has, you are asked to confirm that you want to change
the buffer.
On systems where clash detection (locking of files being edited) is
whether the file has changed on disk since it was last visited or
where the sort keys were `Emacs', `If', `buffer', `systems' and `the'.
`M-x sort-columns' requires more explanation. You specify the
columns by putting point at one of the columns and the mark at the other
column. Because this means you cannot put point or the mark at the
beginning of the first line of the text you want to sort, this command
uses an unusual definition of `region': all of the line point is in is
considered part of the region, and so is all of the line the mark is in,
as well as all the lines in between.
For example, to sort a table by information found in columns 10 to
15, you could put the mark on column 10 in the first line of the table,
and point on column 15 in the last line of the table, and then run
`sort-columns'. Equivalently, you could run it with the mark on column
15 in the first line and point on column 10 in the last line.
This can be thought of as sorting the rectangle specified by point
and the mark, except that the text on each line to the left or right of
the rectangle moves along with the text inside the rectangle. *Note
Rectangles::.
Many of the sort commands ignore case differences when comparing, if
`sort-fold-case' is non-`nil'.
Narrowing
=========
"Narrowing" means focusing in on some portion of the buffer, making
the rest temporarily inaccessible. The portion which you can still get
to is called the "accessible portion". Canceling the narrowing, which
makes the entire buffer once again accessible, is called "widening".
The amount of narrowing in effect in a buffer at any time is called the
buffer's "restriction".
Narrowing can make it easier to concentrate on a single subroutine or
paragraph by eliminating clutter. It can also be used to restrict the
range of operation of a replace command or repeating keyboard macro.
`C-x n n'
Narrow down to between point and mark (`narrow-to-region').
`C-x n w'
Widen to make the entire buffer accessible again (`widen').
`C-x n p'
Narrow down to the current page (`narrow-to-page').
`C-x n d'
Narrow down to the current defun (`narrow-to-defun').
When you have narrowed down to a part of the buffer, that part
appears to be all there is. You can't see the rest, you can't move
into it (motion commands won't go outside the accessible part), you
can't change it in any way. However, it is not gone, and if you save
the file all the inaccessible text will be saved. The word `Narrow'
appears in the mode line whenever narrowing is in effect.
The primary narrowing command is `C-x n n' (`narrow-to-region'). It
sets the current buffer's restrictions so that the text in the current
region remains accessible but all text before the region or after the
region is inaccessible. Point and mark do not change.
Alternatively, use `C-x n p' (`narrow-to-page') to narrow down to
the current page. *Note Pages::, for the definition of a page. `C-x n
d' (`narrow-to-defun') narrows down to the defun containing point
(*note Defuns::.).
The way to cancel narrowing is to widen with `C-x n w' (`widen').
This makes all text in the buffer accessible again.
You can get information on what part of the buffer you are narrowed
down to using the `C-x =' command. *Note Position Info::.
Because narrowing can easily confuse users who do not understand it,
`narrow-to-region' is normally a disabled command. Attempting to use
this command asks for confirmation and gives you the option of enabling
it; if you enable the command, confirmation will no longer be required
for it. *Note Disabling::.
Two-Column Editing
==================
Two-column mode lets you conveniently edit two side-by-side columns
of text. It uses two side-by-side windows, each showing its own buffer.
There are three ways to enter two-column mode:
`<F2> 2' or `C-x 6 2'
Enter two-column mode with the current buffer on the left, and on
the right, a buffer whose name is based on the current buffer's
name (`2C-two-columns'). If the right-hand buffer doesn't already
exist, it starts out empty; the current buffer's contents are not
changed.
This command is appropriate when the current buffer is empty or
contains just one column and you want to add another column.
`<F2> s' or `C-x 6 s'
Split the current buffer, which contains two-column text, into two
buffers, and display them side by side (`2C-split'). The current
buffer becomes the left-hand buffer, but the text in the right-hand
column is moved into the right-hand buffer. The current column
specifies the split point. Splitting starts with the current line
and continues to the end of the buffer.
This command is appropriate when you have a buffer that already
contains two-column text, and you wish to separate the columns
temporarily.
`<F2> b BUFFER <RET>'
`C-x 6 b BUFFER <RET>'
Enter two-column mode using the current buffer as the left-hand
buffer, and using buffer BUFFER as the right-hand buffer
(`2C-associate-buffer').
`<F2> s' or `C-x 6 s' looks for a column separator, which is a
string that appears on each line between the two columns. You can
specify the width of the separator with a numeric argument to `<F2> s';
that many characters, before point, constitute the separator string.
By default, the width is 1, so the column separator is the character
before point.
When a line has the separator at the proper place, `<F2> s' puts the
text after the separator into the right-hand buffer, and deletes the
separator. Lines that don't have the column separator at the proper
place remain unsplit; they stay in the left-hand buffer, and the
right-hand buffer gets an empty line to correspond. (This is the way
to write a line that "spans both columns while in two-column mode":
write it in the left-hand buffer, and put an empty line in the
right-hand buffer.)
The command `C-x 6 <RET>' or `<F2> <RET>' (`2C-newline') inserts a
newline in each of the two buffers at corresponding positions. This is
the easiest way to add a new line to the two-column text while editing
it in split buffers.
When you have edited both buffers as you wish, merge them with `<F2>
1' or `C-x 6 1' (`2C-merge'). This copies the text from the right-hand
buffer as a second column in the other buffer. To go back to
two-column editing, use `<F2> s'.
Use `<F2> d' or `C-x 6 d' to dissociate the two buffers, leaving
each as it stands (`2C-dissociate'). If the other buffer, the one not
current when you type `<F2> d', is empty, `<F2> d' kills it.
Editing Binary Files
====================
There is a special major mode for editing binary files: Hexl mode.
To use it, use `M-x hexl-find-file' instead of `C-x C-f' to visit the
file. This command converts the file's contents to hexadecimal and
lets you edit the translation. When you save the file, it is converted
automatically back to binary.
You can also use `M-x hexl-mode' to translate an existing buffer
into hex. This is useful if you visit a file normally and then discover
it is a binary file.
Ordinary text characters overwrite in Hexl mode. This is to reduce
the risk of accidentally spoiling the alignment of data in the file.
There are special commands for insertion. Here is a list of the
commands of Hexl mode:
`C-M-d'
Insert a byte with a code typed in decimal.
`C-M-o'
Insert a byte with a code typed in octal.
`C-M-x'
Insert a byte with a code typed in hex.
`C-x ['
Move to the beginning of a 1k-byte "page."
`C-x ]'
Move to the end of a 1k-byte "page."
`M-g'
Move to an address specified in hex.
`M-j'
Move to an address specified in decimal.
`C-c C-c'
Leave Hexl mode, going back to the major mode this buffer had
before you invoked `hexl-mode'.
Saving Emacs Sessions
=====================
You can use the Desktop library to save the state of Emacs from one
session to another. Saving the state means that Emacs starts up with
the same set of buffers, major modes, buffer positions, and so on that
the previous Emacs session had.
To use Desktop, you should use the Customization buffer (*note Easy
Customization::.) to set `desktop-enable' to a non-`nil' value, or add
these lines at the end of your `.emacs' file:
(desktop-load-default)
(desktop-read)
The first time you save the state of the Emacs session, you must do it
manually, with the command `M-x desktop-save'. Once you have done
that, exiting Emacs will save the state again--not only the present
Emacs session, but also subsequent sessions. You can also save the
state at any time, without exiting Emacs, by typing `M-x desktop-save'
again.
In order for Emacs to recover the state from a previous session, you
must start it with the same current directory as you used when you
started the previous session. This is because `desktop-read' looks in
the current directory for the file to read. This means that you can
have separate saved sessions in different directories; the directory in
which you start Emacs will control which saved session to use.
The variable `desktop-files-not-to-save' controls which files are
excluded from state saving. Its value is a regular expression that
matches the files to exclude. By default, remote (ftp-accessed) files
are excluded; this is because visiting them again in the subsequent
session would be slow. If you want to include these files in state
saving, set `desktop-files-not-to-save' to `"^$"'. *Note Remote
Files::.
Recursive Editing Levels
========================
A "recursive edit" is a situation in which you are using Emacs
commands to perform arbitrary editing while in the middle of another
Emacs command. For example, when you type `C-r' inside of a
`query-replace', you enter a recursive edit in which you can change the
current buffer. On exiting from the recursive edit, you go back to the
`query-replace'.
"Exiting" the recursive edit means returning to the unfinished
command, which continues execution. The command to exit is `C-M-c'
(`exit-recursive-edit').
You can also "abort" the recursive edit. This is like exiting, but
also quits the unfinished command immediately. Use the command `C-]'
(`abort-recursive-edit') to do this. *Note Quitting::.
The mode line shows you when you are in a recursive edit by
displaying square brackets around the parentheses that always surround
the major and minor mode names. Every window's mode line shows this,
in the same way, since being in a recursive edit is true of Emacs as a
whole rather than any particular window or buffer.
It is possible to be in recursive edits within recursive edits. For
example, after typing `C-r' in a `query-replace', you may type a
command that enters the debugger. This begins a recursive editing level
for the debugger, within the recursive editing level for `C-r'. Mode
lines display a pair of square brackets for each recursive editing
level currently in progress.
Exiting the inner recursive edit (such as, with the debugger `c'
command) resumes the command running in the next level up. When that
command finishes, you can then use `C-M-c' to exit another recursive
editing level, and so on. Exiting applies to the innermost level only.
Aborting also gets out of only one level of recursive edit; it returns
immediately to the command level of the previous recursive edit. If you
wish, you can then abort the next recursive editing level.
Alternatively, the command `M-x top-level' aborts all levels of
recursive edits, returning immediately to the top-level command reader.
The text being edited inside the recursive edit need not be the same
text that you were editing at top level. It depends on what the
recursive edit is for. If the command that invokes the recursive edit
selects a different buffer first, that is the buffer you will edit
recursively. In any case, you can switch buffers within the recursive
edit in the normal manner (as long as the buffer-switching keys have
not been rebound). You could probably do all the rest of your editing
inside the recursive edit, visiting files and all. But this could have
surprising effects (such as stack overflow) from time to time. So
remember to exit or abort the recursive edit when you no longer need it.
In general, we try to minimize the use of recursive editing levels in
GNU Emacs. This is because they constrain you to "go back" in a
particular order--from the innermost level toward the top level. When
possible, we present different activities in separate buffers so that
you can switch between them as you please. Some commands switch to a
new major mode which provides a command to switch back. These
approaches give you more flexibility to go back to unfinished tasks in
the order you choose.
Emulation
=========
GNU Emacs can be programmed to emulate (more or less) most other
editors. Standard facilities can emulate these:
EDT (DEC VMS editor)
Turn on EDT emulation with `M-x edt-emulation-on'. `M-x
edt-emulation-off' restores normal Emacs command bindings.
Most of the EDT emulation commands are keypad keys, and most
standard Emacs key bindings are still available. The EDT
emulation rebindings are done in the global keymap, so there is no
problem switching buffers or major modes while in EDT emulation.
vi (Berkeley editor)
Viper is the newest emulator for vi. It implements several levels
of emulation; level 1 is closest to vi itself, while level 5
departs somewhat from strict emulation to take advantage of the
capabilities of Emacs. To invoke Viper, type `M-x viper-mode'; it
will guide you the rest of the way and ask for the emulation
level. *note Viper: (viper)Top.
vi (another emulator)
`M-x vi-mode' enters a major mode that replaces the previously
established major mode. All of the vi commands that, in real vi,
enter "input" mode are programmed instead to return to the
previous major mode. Thus, ordinary Emacs serves as vi's "input"
mode.
Because vi emulation works through major modes, it does not work
to switch buffers during emulation. Return to normal Emacs first.
If you plan to use vi emulation much, you probably want to bind a
key to the `vi-mode' command.
vi (alternate emulator)
`M-x vip-mode' invokes another vi emulator, said to resemble real
vi more thoroughly than `M-x vi-mode'. "Input" mode in this
emulator is changed from ordinary Emacs so you can use <ESC> to go
back to emulated vi command mode. To get from emulated vi command
mode back to ordinary Emacs, type `C-z'.
This emulation does not work through major modes, and it is
possible to switch buffers in various ways within the emulator.
It is not so necessary to assign a key to the command `vip-mode' as
it is with `vi-mode' because terminating insert mode does not use
it.
*note VIP: (vip)Top, for full information.
Dissociated Press
=================
`M-x dissociated-press' is a command for scrambling a file of text
either word by word or character by character. Starting from a buffer
of straight English, it produces extremely amusing output. The input
comes from the current Emacs buffer. Dissociated Press writes its
output in a buffer named `*Dissociation*', and redisplays that buffer
after every couple of lines (approximately) so you can read the output
as it comes out.
Dissociated Press asks every so often whether to continue generating
output. Answer `n' to stop it. You can also stop at any time by
typing `C-g'. The dissociation output remains in the `*Dissociation*'
buffer for you to copy elsewhere if you wish.
Dissociated Press operates by jumping at random from one point in the
buffer to another. In order to produce plausible output rather than
gibberish, it insists on a certain amount of overlap between the end of
one run of consecutive words or characters and the start of the next.
That is, if it has just printed out `president' and then decides to jump
to a different point in the file, it might spot the `ent' in `pentagon'
and continue from there, producing `presidentagon'.(1) Long sample
texts produce the best results.
A positive argument to `M-x dissociated-press' tells it to operate
character by character, and specifies the number of overlap characters.
A negative argument tells it to operate word by word and specifies the
number of overlap words. In this mode, whole words are treated as the
elements to be permuted, rather than characters. No argument is
equivalent to an argument of two. For your againformation, the output
goes only into the buffer `*Dissociation*'. The buffer you start with
is not changed.
Dissociated Press produces nearly the same results as a Markov chain
based on a frequency table constructed from the sample text. It is,
however, an independent, ignoriginal invention. Dissociated Press
techniquitously copies several consecutive characters from the sample
between random choices, whereas a Markov chain would choose randomly for
each word or character. This makes for more plausible sounding results,
and runs faster.
It is a mustatement that too much use of Dissociated Press can be a
developediment to your real work. Sometimes to the point of outragedy.
And keep dissociwords out of your documentation, if you want it to be
well userenced and properbose. Have fun. Your buggestions are welcome.
---------- Footnotes ----------
(1) This dissociword actually appeared during the Vietnam War, when
it was very appropriate.
Other Amusements
================
If you are a little bit bored, you can try `M-x hanoi'. If you are
considerably bored, give it a numeric argument. If you are very very
bored, try an argument of 9. Sit back and watch.
If you want a little more personal involvement, try `M-x gomoku',
which plays the game Go Moku with you.
`M-x blackbox' and `M-x mpuz' are two kinds of puzzles. `blackbox'
challenges you to determine the location of objects inside a box by
tomography. `mpuz' displays a multiplication puzzle with letters
standing for digits in a code that you must guess--to guess a value,
type a letter and then the digit you think it stands for.
`M-x dunnet' runs an adventure-style exploration game, which is a
bigger sort of puzzle.
When you are frustrated, try the famous Eliza program. Just do `M-x
doctor'. End each input by typing <RET> twice.
When you are feeling strange, type `M-x yow'.
Customization
*************
This chapter talks about various topics relevant to adapting the
behavior of Emacs in minor ways. See `The Emacs Lisp Reference Manual'
for how to make more far-reaching changes.
All kinds of customization affect only the particular Emacs session
that you do them in. They are completely lost when you kill the Emacs
session, and have no effect on other Emacs sessions you may run at the
same time or later. The only way an Emacs session can affect anything
outside of it is by writing a file; in particular, the only way to make
a customization "permanent" is to put something in your `.emacs' file
or other appropriate file to do the customization in each session.
*Note Init File::.
Minor Modes
===========
Minor modes are optional features which you can turn on or off. For
example, Auto Fill mode is a minor mode in which <SPC> breaks lines
between words as you type. All the minor modes are independent of each
other and of the selected major mode. Most minor modes say in the mode
line when they are on; for example, `Fill' in the mode line means that
Auto Fill mode is on.
Append `-mode' to the name of a minor mode to get the name of a
command function that turns the mode on or off. Thus, the command to
enable or disable Auto Fill mode is called `M-x auto-fill-mode'. These
commands are usually invoked with `M-x', but you can bind keys to them
if you wish. With no argument, the function turns the mode on if it was
off and off if it was on. This is known as "toggling". A positive
argument always turns the mode on, and an explicit zero argument or a
negative argument always turns it off.
Enabling or disabling some minor modes applies only to the current
buffer; each buffer is independent of the other buffers. Therefore, you
can enable the mode in particular buffers and disable it in others. The
per-buffer minor modes include Abbrev mode, Auto Fill mode, Auto Save
mode, Font-Lock mode, Hscroll mode, ISO Accents mode, Outline minor
mode, Overwrite mode, and Binary Overwrite mode.
Abbrev mode allows you to define abbreviations that automatically
expand as you type them. For example, `amd' might expand to `abbrev
mode'. *Note Abbrevs::, for full information.
Auto Fill mode allows you to enter filled text without breaking lines
explicitly. Emacs inserts newlines as necessary to prevent lines from
becoming too long. *Note Filling::.
Auto Save mode causes the contents of a buffer to be saved
periodically to reduce the amount of work you can lose in case of a
system crash. *Note Auto Save::.
Enriched mode enables editing and saving of formatted text. *Note
Formatted Text::.
Flyspell mode automatically highlights misspelled words. *Note
Spelling::.
Font-Lock mode automatically highlights certain textual units found
in programs, such as comments, strings, and function names being
defined. This requires a window system that can display multiple fonts.
*Note Faces::.
Hscroll mode performs horizontal scrolling automatically to keep
point on the screen. *Note Horizontal Scrolling::.
ISO Accents mode makes the characters ``', `'', `"', `^', `/' and
`~' combine with the following letter, to produce an accented letter in
the ISO Latin-1 character set. *Note Single-Byte European Support::.
Outline minor mode provides the same facilities as the major mode
called Outline mode; but since it is a minor mode instead, you can
combine it with any major mode. *Note Outline Mode::.
Overwrite mode causes ordinary printing characters to replace
existing text instead of shoving it to the right. For example, if
point is in front of the `B' in `FOOBAR', then in Overwrite mode typing
a `G' changes it to `FOOGAR', instead of producing `FOOGBAR' as usual.
In Overwrite mode, the command `C-q' inserts the next character
whatever it may be, even if it is a digit--this gives you a way to
insert a character instead of replacing an existing character.
Binary Overwrite mode is a variant of Overwrite mode for editing
binary files; it treats newlines and tabs like other characters, so that
they overwrite other characters and can be overwritten by them.
The following minor modes normally apply to all buffers at once.
Since each is enabled or disabled by the value of a variable, you *can*
set them differently for particular buffers, by explicitly making the
corresponding variables local in those buffers. *Note Locals::.
Icomplete mode displays an indication of available completions when
you are in the minibuffer and completion is active. *Note Completion
Options::.
Line Number mode enables continuous display in the mode line of the
line number of point. *Note Mode Line::.
Resize-Minibuffer mode makes the minibuffer expand as necessary to
hold the text that you put in it. *Note Minibuffer Edit::.
Scroll Bar mode gives each window a scroll bar (*note Scroll
Bars::.). Menu Bar mode gives each frame a menu bar (*note Menu
Bars::.). Both of these modes are enabled by default when you use the
X Window System.
In Transient Mark mode, every change in the buffer contents
"deactivates" the mark, so that commands that operate on the region
will get an error. This means you must either set the mark, or
explicitly "reactivate" it, before each command that uses the region.
The advantage of Transient Mark mode is that Emacs can display the
region highlighted (currently only when using X). *Note Setting Mark::.
For most minor modes, the command name is also the name of a variable
which directly controls the mode. The mode is enabled whenever this
variable's value is non-`nil', and the minor-mode command works by
setting the variable. For example, the command `outline-minor-mode'
works by setting the value of `outline-minor-mode' as a variable; it is
this variable that directly turns Outline minor mode on and off. To
check whether a given minor mode works this way, use `C-h v' to ask for
documentation on the variable name.
These minor-mode variables provide a good way for Lisp programs to
turn minor modes on and off; they are also useful in a file's local
variables list. But please think twice before setting minor modes with
a local variables list, because most minor modes are matter of user
preference--other users editing the same file might not want the same
minor modes you prefer.
Variables
=========
A "variable" is a Lisp symbol which has a value. The symbol's name
is also called the name of the variable. A variable name can contain
any characters that can appear in a file, but conventionally variable
names consist of words separated by hyphens. A variable can have a
documentation string which describes what kind of value it should have
and how the value will be used.
Lisp allows any variable to have any kind of value, but most
variables that Emacs uses require a value of a certain type. Often the
value should always be a string, or should always be a number.
Sometimes we say that a certain feature is turned on if a variable is
"non-`nil'," meaning that if the variable's value is `nil', the feature
is off, but the feature is on for *any* other value. The conventional
value to use to turn on the feature--since you have to pick one
particular value when you set the variable--is `t'.
Emacs uses many Lisp variables for internal record keeping, as any
Lisp program must, but the most interesting variables for you are the
ones that exist for the sake of customization. Emacs does not (usually)
change the values of these variables; instead, you set the values, and
thereby alter and control the behavior of certain Emacs commands. These
variables are called "user options". Most user options are documented
in this manual, and appear in the Variable Index (*note Variable
Index::.).
One example of a variable which is a user option is `fill-column',
which specifies the position of the right margin (as a number of
characters from the left margin) to be used by the fill commands (*note
Filling::.).
Examining and Setting Variables
-------------------------------
`C-h v VAR <RET>'
Display the value and documentation of variable VAR
(`describe-variable').
`M-x set-variable <RET> VAR <RET> VALUE <RET>'
Change the value of variable VAR to VALUE.
To examine the value of a single variable, use `C-h v'
(`describe-variable'), which reads a variable name using the
minibuffer, with completion. It displays both the value and the
documentation of the variable. For example,
C-h v fill-column <RET>
displays something like this:
fill-column's value is 75
Documentation:
*Column beyond which automatic line-wrapping should happen.
Automatically becomes buffer-local when set in any fashion.
The star at the beginning of the documentation indicates that this
variable is a user option. `C-h v' is not restricted to user options;
it allows any variable name.
The most convenient way to set a specific user option is with `M-x
set-variable'. This reads the variable name with the minibuffer (with
completion), and then reads a Lisp expression for the new value using
the minibuffer a second time. For example,
M-x set-variable <RET> fill-column <RET> 75 <RET>
sets `fill-column' to 75.
`M-x set-variable' is limited to user option variables, but you can
set any variable with a Lisp expression, using the function `setq'.
Here is a `setq' expression to set `fill-column':
(setq fill-column 75)
To execute an expression like this one, go to the `*scratch*'
buffer, type in the expression, and then type `C-j'. *Note Lisp
Interaction::.
Setting variables, like all means of customizing Emacs except where
otherwise stated, affects only the current Emacs session.
Easy Customization Interface
----------------------------
A convenient way to find the user option variables that you want to
change, and then change them, is with `M-x customize'. This command
creates a "customization buffer" with which you can browse through the
Emacs user options in a logically organized structure, then edit and
set their values. You can also use the customization buffer to save
settings permanently. (Not all Emacs user options are included in this
structure as of yet, but we are adding the rest.)
Customization Groups
....................
For customization purposes, user options are organized into "groups"
to help you find them. Groups are collected into bigger groups, all
the way up to a master group called `Emacs'.
`M-x customize' creates a customization buffer that shows the
top-level `Emacs' group and the second-level groups immediately under
it. It looks like this, in part:
/- Emacs group: ---------------------------------------------------\
[State]: visible group members are all at standard settings.
Customization of the One True Editor.
See also [Manual].
Editing group: [Go to Group]
Basic text editing facilities.
External group: [Go to Group]
Interfacing to external utilities.
MORE SECOND-LEVEL GROUPS
\- Emacs group end ------------------------------------------------/
This says that the buffer displays the contents of the `Emacs' group.
The other groups are listed because they are its contents. But they
are listed differently, without indentation and dashes, because *their*
contents are not included. Each group has a single-line documentation
string; the `Emacs' group also has a `[State]' line.
Most of the text in the customization buffer is read-only, but it
typically includes some "editable fields" that you can edit. There are
also "active fields"; this means a field that does something when you
"invoke" it. To invoke an active field, either click on it with
`Mouse-1', or move point to it and type <RET>.
For example, the phrase `[Go to Group]' that appears in a
second-level group is an active field. Invoking the `[Go to Group]'
field for a group creates a new customization buffer, which shows that
group and its contents. This field is a kind of hypertext link to
another group.
The `Emacs' group does not include any user options itself, but
other groups do. By examining various groups, you will eventually find
the options and faces that belong to the feature you are interested in
customizing. Then you can use the customization buffer to set them.
You can view the structure of customization groups on a larger scale
with `M-x customize-browse'. This command creates a special kind of
customization buffer which shows only the names of the groups (and
options and faces), and their structure.
In this buffer, you can show the contents of a group by invoking
`[+]'. When the group contents are visible, this button changes to
`[-]'; invoking that hides the group contents.
Each group, option or face name in this buffer has an active field
which says `[Group]', `[Option]' or `[Face]'. Invoking that active
field creates an ordinary customization buffer showing just that group
and its contents, just that option, or just that face. This is the way
to set values in it.
Changing an Option
..................
Here is an example of what a user option looks like in the
customization buffer:
Kill Ring Max: [Hide] 30
[State]: this option is unchanged from its standard setting.
Maximum length of kill ring before oldest elements are thrown away.
The text following `[Hide]', `30' in this case, indicates the
current value of the option. If you see `[Show]' instead of `[Hide]',
it means that the value is hidden; the customization buffer initially
hides values that take up several lines. Invoke `[Show]' to show the
value.
The line after the option name indicates the "customization state"
of the option: in the example above, it says you have not changed the
option yet. The word `[State]' at the beginning of this line is
active; you can get a menu of various operations by invoking it with
`Mouse-1' or <RET>. These operations are essential for customizing the
variable.
The line after the `[State]' line displays the beginning of the
option's documentation string. If there are more lines of
documentation, this line ends with `[More]'; invoke this to show the
full documentation string.
To enter a new value for `Kill Ring Max', move point to the value
and edit it textually. For example, you can type `M-d', then insert
another number.
When you begin to alter the text, you will see the `[State]' line
change to say that you have edited the value:
[State]: you have edited the value as text, but not set the option.
Editing the value does not actually set the option variable. To do
that, you must "set" the option. To do this, invoke the word `[State]'
and choose `Set for Current Session'.
The state of the option changes visibly when you set it:
[State]: you have set this option, but not saved it for future sessions.
You don't have to worry about specifying a value that is not valid;
setting the option checks for validity and will not really install an
unacceptable value.
While editing a value or field that is a file name, directory name,
command name, or anything else for which completion is defined, you can
type `M-<TAB>' (`widget-complete') to do completion.
Some options have a small fixed set of possible legitimate values.
These options don't let you edit the value textually. Instead, an
active field `[Value Menu]' appears before the value; invoke this field
to edit the value. For a boolean "on or off" value, the active field
says `[Toggle]', and it changes to the other value. `[Value Menu]' and
`[Toggle]' edit the buffer; the changes take effect when you use the
`Set for Current Session' operation.
Some options have values with complex structure. For example, the
value of `load-path' is a list of directories. Here is how it appears
in the customization buffer:
Load Path:
[INS] [DEL] [Current dir?]: /usr/local/share/emacs/20.3/site-lisp
[INS] [DEL] [Current dir?]: /usr/local/share/emacs/site-lisp
[INS] [DEL] [Current dir?]: /usr/local/share/emacs/20.3/leim
[INS] [DEL] [Current dir?]: /usr/local/share/emacs/20.3/lisp
[INS] [DEL] [Current dir?]: /build/emacs/e20/lisp
[INS] [DEL] [Current dir?]: /build/emacs/e20/lisp/gnus
[INS]
[State]: this item has been changed outside the customization buffer.
List of directories to search for files to load....
Each directory in the list appears on a separate line, and each line has
several editable or active fields.
You can edit any of the directory names. To delete a directory from
the list, invoke `[DEL]' on that line. To insert a new directory in
the list, invoke `[INS]' at the point where you want to insert it.
You can also invoke `[Current dir?]' to switch between including a
specific named directory in the path, and including `nil' in the path.
(`nil' in a search path means "try the current directory.")
Two special commands, <TAB> and `S-<TAB>', are useful for moving
through the customization buffer. <TAB> (`widget-forward') moves
forward to the next active or editable field; `S-<TAB>'
(`widget-backward') moves backward to the previous active or editable
field.
Typing <RET> on an editable field also moves forward, just like
<TAB>. The reason for this is that people have a tendency to type
<RET> when they are finished editing a field. If you have occasion to
insert a newline in an editable field, use `C-o' or `C-q C-j'.
Setting the option changes its value in the current Emacs session;
"saving" the value changes it for future sessions as well. This works
by writing code into your `~/.emacs' file so as to set the option
variable again each time you start Emacs. To save the option, invoke
`[State]' and select the `Save for Future Sessions' operation.
You can also restore the option to its standard value by invoking
`[State]' and selecting the `Reset to Standard Settings' operation.
There are actually three reset operations:
`Reset'
If you have made some modifications and not yet set the option,
this restores the text in the customization buffer to match the
actual value.
`Reset to Saved'
This restores the value of the option to the last saved value, and
updates the text accordingly.
`Reset to Standard Settings'
This sets the option to its standard value, and updates the text
accordingly. This also eliminates any saved value for the option,
so that you will get the standard value in future Emacs sessions.
The state of a group indicates whether anything in that group has
been edited, set or saved. You can select `Set for Current Session',
`Save for Future Sessions' and the various kinds of `Reset' operation
for the group; these operations on the group apply to all options in
the group and its subgroups.
Near the top of the customization buffer there are two lines
containing several active fields:
[Set for Current Session] [Save for Future Sessions]
[Reset] [Reset to Saved] [Reset to Standard] [Bury Buffer]
Invoking `[Bury Buffer]' buries this customization buffer. Each of the
other fields performs an operation--set, save or reset--on each of the
items in the buffer that could meaningfully be set, saved or reset.
Customizing Faces
.................
In addition to user options, some customization groups also include
faces. When you show the contents of a group, both the user options and
the faces in the group appear in the customization buffer. Here is an
example of how a face looks:
Custom Changed Face: (sample)
[State]: this face is unchanged from its standard setting.
Face used when the customize item has been changed.
Attributes: [ ] Bold: [toggle] off
[X] Italic: [toggle] on
[ ] Underline: [toggle] off
[ ] Inverse-Video: [toggle] on
[ ] Foreground: black (sample)
[ ] Background: white (sample)
[ ] Stipple:
Each face attribute has its own line. The `[X]' field before the
attribute name indicates whether the attribute is "enabled"; `X' means
that it is. You can enable or disable the attribute by invoking that
field. When the attribute is enabled, you can change the attribute
value in the usual ways.
On a black-and-white display, the colors you can use for the
background are `black', `white', `gray', `gray1', and `gray3'. Emacs
supports these shades of gray by using background stipple patterns
instead of a color.
Setting, saving and resetting a face work like the same operations
for options (*note Changing an Option::.).
A face can specify different appearances for different types of
display. For example, a face can make text red on a color display, but
use a bold font on a monochrome display. To specify multiple
appearances for a face, select `Show Display Types' in the menu you get
from invoking `[State]'.
Another more basic way to set the attributes of a specific face is
with `M-x modify-face'. This command reads the name of a face, then
reads the attributes one by one. For the color and stipple attributes,
the attribute's current value is the default--type just <RET> if you
don't want to change that attribute. Type `none' if you want to clear
out the attribute.
Customizing Specific Items
..........................
Instead of finding the options you want to change by moving down
through the structure of groups, you can specify the particular option,
face or group that you want to customize.
`M-x customize-option <RET> OPTION <RET>'
Set up a customization buffer with just one option, OPTION.
`M-x customize-face <RET> FACE <RET>'
Set up a customization buffer with just one face, FACE.
`M-x customize-group <RET> GROUP <RET>'
Set up a customization buffer with just one group, GROUP.
`M-x customize-apropos <RET> REGEXP <RET>'
Set up a customization buffer with all the options, faces and
groups that match REGEXP.
`M-x customize-changed-options <RET> VERSION <RET>'
Set up a customization buffer with all the options, faces and
groups whose meaning has changed since Emacs version VERSION.
`M-x customize-saved'
Set up a customization buffer containing all options and faces
that you have saved with customization buffers.
`M-x customize-customized'
Set up a customization buffer containing all options and faces
that you have customized but not saved.
If you want to alter a particular user option variable with the
customization buffer, and you know its name, you can use the command
`M-x customize-option' and specify the option name. This sets up the
customization buffer with just one option--the one that you asked for.
Editing, setting and saving the value work as described above, but only
for the specified option.
Likewise, you can modify a specific face, chosen by name, using `M-x
customize-face'.
You can also set up the customization buffer with a specific group,
using `M-x customize-group'. The immediate contents of the chosen
group, including option variables, faces, and other groups, all appear
as well. However, these subgroups' own contents start out hidden. You
can show their contents in the usual way, by invoking `[Show]'.
To control more precisely what to customize, you can use `M-x
customize-apropos'. You specify a regular expression as argument; then
all options, faces and groups whose names match this regular expression
are set up in the customization buffer. If you specify an empty regular
expression, this includes *all* groups, options and faces in the
customization buffer (but that takes a long time).
When you upgrade to a new Emacs version, you might want to customize
new options and options whose meanings or default values have changed.
To do this, use `M-x customize-changed-options' and specify a previous
Emacs version number using the minibuffer. It creates a customization
buffer which shows all the options (and groups) whose definitions have
been changed since the specified version.
If you change option values and then decide the change was a mistake,
you can use two special commands to revisit your previous changes. Use
`customize-saved' to look at the options and faces that you have saved.
Use `M-x customize-customized' to look at the options and faces that
you have set but not saved.
Hooks
-----
A "hook" is a variable where you can store a function or functions
to be called on a particular occasion by an existing program. Emacs
provides a number of hooks for the sake of customization.
Most of the hooks in Emacs are "normal hooks". These variables
contain lists of functions to be called with no arguments. The reason
most hooks are normal hooks is so that you can use them in a uniform
way. Every variable in Emacs whose name ends in `-hook' is a normal
hook.
Most major modes run hooks as the last step of initialization. This
makes it easy for a user to customize the behavior of the mode, by
overriding the local variable assignments already made by the mode. But
hooks may also be used in other contexts. For example, the hook
`suspend-hook' runs just before Emacs suspends itself (*note
Exiting::.).
The recommended way to add a hook function to a normal hook is by
calling `add-hook'. You can use any valid Lisp function as the hook
function. For example, here's how to set up a hook to turn on Auto
Fill mode when entering Text mode and other modes based on Text mode:
(add-hook 'text-mode-hook 'turn-on-auto-fill)
The next example shows how to use a hook to customize the indentation
of C code. (People often have strong personal preferences for one
format compared to another.) Here the hook function is an anonymous
lambda expression.
(setq my-c-style
'((c-comment-only-line-offset . 4)
(c-cleanup-list . (scope-operator
empty-defun-braces
defun-close-semi))
(c-offsets-alist . ((arglist-close . c-lineup-arglist)
(substatement-open . 0)))))
(add-hook 'c-mode-common-hook
(function (lambda ()
(c-add-style "my-style" my-c-style t))))
It is best to design your hook functions so that the order in which
they are executed does not matter. Any dependence on the order is
"asking for trouble." However, the order is predictable: the most
recently added hook functions are executed first.
Local Variables
---------------
`M-x make-local-variable <RET> VAR <RET>'
Make variable VAR have a local value in the current buffer.
`M-x kill-local-variable <RET> VAR <RET>'
Make variable VAR use its global value in the current buffer.
`M-x make-variable-buffer-local <RET> VAR <RET>'
Mark variable VAR so that setting it will make it local to the
buffer that is current at that time.
Almost any variable can be made "local" to a specific Emacs buffer.
This means that its value in that buffer is independent of its value in
other buffers. A few variables are always local in every buffer.
Every other Emacs variable has a "global" value which is in effect in
all buffers that have not made the variable local.
`M-x make-local-variable' reads the name of a variable and makes it
local to the current buffer. Further changes in this buffer will not
affect others, and further changes in the global value will not affect
this buffer.
`M-x make-variable-buffer-local' reads the name of a variable and
changes the future behavior of the variable so that it will become local
automatically when it is set. More precisely, once a variable has been
marked in this way, the usual ways of setting the variable automatically
do `make-local-variable' first. We call such variables "per-buffer"
variables.
Major modes (*note Major Modes::.) always make variables local to the
buffer before setting the variables. This is why changing major modes
in one buffer has no effect on other buffers. Minor modes also work by
setting variables--normally, each minor mode has one controlling
variable which is non-`nil' when the mode is enabled (*note Minor
Modes::.). For most minor modes, the controlling variable is per
buffer.
Emacs contains a number of variables that are always per-buffer.
These include `abbrev-mode', `auto-fill-function', `case-fold-search',
`comment-column', `ctl-arrow', `fill-column', `fill-prefix',
`indent-tabs-mode', `left-margin', `mode-line-format', `overwrite-mode',
`selective-display-ellipses', `selective-display', `tab-width', and
`truncate-lines'. Some other variables are always local in every
buffer, but they are used for internal purposes.
A few variables cannot be local to a buffer because they are always
local to each display instead (*note Multiple Displays::.). If you try
to make one of these variables buffer-local, you'll get an error
message.
`M-x kill-local-variable' reads the name of a variable and makes it
cease to be local to the current buffer. The global value of the
variable henceforth is in effect in this buffer. Setting the major mode
kills all the local variables of the buffer except for a few variables
specially marked as "permanent locals".
To set the global value of a variable, regardless of whether the
variable has a local value in the current buffer, you can use the Lisp
construct `setq-default'. This construct is used just like `setq', but
it sets variables' global values instead of their local values (if
any). When the current buffer does have a local value, the new global
value may not be visible until you switch to another buffer. Here is
an example:
(setq-default fill-column 75)
`setq-default' is the only way to set the global value of a variable
that has been marked with `make-variable-buffer-local'.
Lisp programs can use `default-value' to look at a variable's
default value. This function takes a symbol as argument and returns its
default value. The argument is evaluated; usually you must quote it
explicitly. For example, here's how to obtain the default value of
`fill-column':
(default-value 'fill-column)
Local Variables in Files
------------------------
A file can specify local variable values for use when you edit the
file with Emacs. Visiting the file checks for local variable
specifications; it automatically makes these variables local to the
buffer, and sets them to the values specified in the file.
There are two ways to specify local variable values: in the first
line, or with a local variables list. Here's how to specify them in the
first line:
-*- mode: MODENAME; VAR: VALUE; ... -*-
You can specify any number of variables/value pairs in this way, each
pair with a colon and semicolon as shown above. `mode: MODENAME;'
specifies the major mode; this should come first in the line. The
VALUEs are not evaluated; they are used literally. Here is an example
that specifies Lisp mode and sets two variables with numeric values:
;; -*-mode: Lisp; fill-column: 75; comment-column: 50; -*-
You can also specify the coding system for a file in this way: just
specify a value for the "variable" named `coding'. The "value" must be
a coding system name that Emacs recognizes. *Note Coding Systems::.
A "local variables list" goes near the end of the file, in the last
page. (It is often best to put it on a page by itself.) The local
variables list starts with a line containing the string `Local
Variables:', and ends with a line containing the string `End:'. In
between come the variable names and values, one set per line, as
`VARIABLE: VALUE'. The VALUEs are not evaluated; they are used
literally. If a file has both a local variables list and a `-*-' line,
Emacs processes *everything* in the `-*-' line first, and *everything*
in the local variables list afterward.
Here is an example of a local variables list:
;;; Local Variables: ***
;;; mode:lisp ***
;;; comment-column:0 ***
;;; comment-start: ";;; " ***
;;; comment-end:"***" ***
;;; End: ***
As you see, each line starts with the prefix `;;; ' and each line
ends with the suffix ` ***'. Emacs recognizes these as the prefix and
suffix based on the first line of the list, by finding them surrounding
the magic string `Local Variables:'; then it automatically discards
them from the other lines of the list.
The usual reason for using a prefix and/or suffix is to embed the
local variables list in a comment, so it won't confuse other programs
that the file is intended as input for. The example above is for a
language where comment lines start with `;;; ' and end with `***'; the
local values for `comment-start' and `comment-end' customize the rest
of Emacs for this unusual syntax. Don't use a prefix (or a suffix) if
you don't need one.
Two "variable names" have special meanings in a local variables
list: a value for the variable `mode' really sets the major mode, and a
value for the variable `eval' is simply evaluated as an expression and
the value is ignored. `mode' and `eval' are not real variables;
setting variables named `mode' and `eval' in any other context has no
special meaning. If `mode' is used to set a major mode, it should be
the first "variable" in the list.
You can use the `mode' "variable" to set minor modes as well as
major modes; in fact, you can use it more than once, first to set the
major mode and then to set minor modes which are specific to particular
buffers. But most minor modes should not be specified in the file in
any fashion, because they represent user preferences.
For example, you may be tempted to try to turn on Auto Fill mode with
a local variable list. That is a mistake. The choice of Auto Fill mode
or not is a matter of individual taste, not a matter of the contents of
particular files. If you want to use Auto Fill, set up major mode hooks
with your `.emacs' file to turn it on (when appropriate) for you alone
(*note Init File::.). Don't use a local variable list to impose your
taste on everyone.
The start of the local variables list must be no more than 3000
characters from the end of the file, and must be in the last page if the
file is divided into pages. Otherwise, Emacs will not notice it is
there. The purpose of this rule is so that a stray `Local Variables:'
not in the last page does not confuse Emacs, and so that visiting a
long file that is all one page and has no local variables list need not
take the time to search the whole file.
Use the command `normal-mode' to reset the local variables and major
mode of a buffer according to the file name and contents, including the
local variables list if any. *Note Choosing Modes::.
The variable `enable-local-variables' controls whether to process
local variables in files, and thus gives you a chance to override them.
Its default value is `t', which means do process local variables in
files. If you set the value to `nil', Emacs simply ignores local
variables in files. Any other value says to query you about each file
that has local variables, showing you the local variable specifications
so you can judge.
The `eval' "variable," and certain actual variables, create a
special risk; when you visit someone else's file, local variable
specifications for these could affect your Emacs in arbitrary ways.
Therefore, the option `enable-local-eval' controls whether Emacs
processes `eval' variables, as well variables with names that end in
`-hook', `-hooks', `-function' or `-functions', and certain other
variables. The three possibilities for the option's value are `t',
`nil', and anything else, just as for `enable-local-variables'. The
default is `maybe', which is neither `t' nor `nil', so normally Emacs
does ask for confirmation about file settings for these variables.
Keyboard Macros
===============
A "keyboard macro" is a command defined by the user to stand for
another sequence of keys. For example, if you discover that you are
about to type `C-n C-d' forty times, you can speed your work by
defining a keyboard macro to do `C-n C-d' and calling it with a repeat
count of forty.
`C-x ('
Start defining a keyboard macro (`start-kbd-macro').
`C-x )'
End the definition of a keyboard macro (`end-kbd-macro').
`C-x e'
Execute the most recent keyboard macro (`call-last-kbd-macro').
`C-u C-x ('
Re-execute last keyboard macro, then add more keys to its
definition.
`C-x q'
When this point is reached during macro execution, ask for
confirmation (`kbd-macro-query').
`M-x name-last-kbd-macro'
Give a command name (for the duration of the session) to the most
recently defined keyboard macro.
`M-x insert-kbd-macro'
Insert in the buffer a keyboard macro's definition, as Lisp code.
`C-x C-k'
Edit a previously defined keyboard macro (`edit-kbd-macro').
`M-x apply-macro-to-region-lines'
Run the last keyboard macro on each complete line in the region.
Keyboard macros differ from ordinary Emacs commands in that they are
written in the Emacs command language rather than in Lisp. This makes
it easier for the novice to write them, and makes them more convenient
as temporary hacks. However, the Emacs command language is not powerful
enough as a programming language to be useful for writing anything
intelligent or general. For such things, Lisp must be used.
You define a keyboard macro while executing the commands which are
the definition. Put differently, as you define a keyboard macro, the
definition is being executed for the first time. This way, you can see
what the effects of your commands are, so that you don't have to figure
them out in your head. When you are finished, the keyboard macro is
defined and also has been, in effect, executed once. You can then do
the whole thing over again by invoking the macro.
Basic Use
---------
To start defining a keyboard macro, type the `C-x (' command
(`start-kbd-macro'). From then on, your keys continue to be executed,
but also become part of the definition of the macro. `Def' appears in
the mode line to remind you of what is going on. When you are
finished, the `C-x )' command (`end-kbd-macro') terminates the
definition (without becoming part of it!). For example,
C-x ( M-f foo C-x )
defines a macro to move forward a word and then insert `foo'.
The macro thus defined can be invoked again with the `C-x e' command
(`call-last-kbd-macro'), which may be given a repeat count as a numeric
argument to execute the macro many times. `C-x )' can also be given a
repeat count as an argument, in which case it repeats the macro that
many times right after defining it, but defining the macro counts as
the first repetition (since it is executed as you define it).
Therefore, giving `C-x )' an argument of 4 executes the macro
immediately 3 additional times. An argument of zero to `C-x e' or `C-x
)' means repeat the macro indefinitely (until it gets an error or you
type `C-g' or, on MS-DOS, `C-<BREAK>').
If you wish to repeat an operation at regularly spaced places in the
text, define a macro and include as part of the macro the commands to
move to the next place you want to use it. For example, if you want to
change each line, you should position point at the start of a line, and
define a macro to change that line and leave point at the start of the
next line. Then repeating the macro will operate on successive lines.
After you have terminated the definition of a keyboard macro, you
can add to the end of its definition by typing `C-u C-x ('. This is
equivalent to plain `C-x (' followed by retyping the whole definition
so far. As a consequence it re-executes the macro as previously
defined.
You can use function keys in a keyboard macro, just like keyboard
keys. You can even use mouse events, but be careful about that: when
the macro replays the mouse event, it uses the original mouse position
of that event, the position that the mouse had while you were defining
the macro. The effect of this may be hard to predict. (Using the
current mouse position would be even less predictable.)
One thing that doesn't always work well in a keyboard macro is the
command `C-M-c' (`exit-recursive-edit'). When this command exits a
recursive edit that started within the macro, it works as you'd expect.
But if it exits a recursive edit that started before you invoked the
keyboard macro, it also necessarily exits the keyboard macro as part of
the process.
You can edit a keyboard macro already defined by typing `C-x C-k'
(`edit-kbd-macro'). Follow that with the keyboard input that you would
use to invoke the macro--`C-x e' or `M-x NAME' or some other key
sequence. This formats the macro definition in a buffer and enters a
specialized major mode for editing it. Type `C-h m' once in that
buffer to display details of how to edit the macro. When you are
finished editing, type `C-c C-c'.
The command `M-x apply-macro-to-region-lines' repeats the last
defined keyboard macro on each complete line within the current region.
It does this line by line, by moving point to the beginning of the line
and then executing the macro.
Naming and Saving Keyboard Macros
---------------------------------
If you wish to save a keyboard macro for longer than until you
define the next one, you must give it a name using `M-x
name-last-kbd-macro'. This reads a name as an argument using the
minibuffer and defines that name to execute the macro. The macro name
is a Lisp symbol, and defining it in this way makes it a valid command
name for calling with `M-x' or for binding a key to with
`global-set-key' (*note Keymaps::.). If you specify a name that has a
prior definition other than another keyboard macro, an error message is
printed and nothing is changed.
Once a macro has a command name, you can save its definition in a
file. Then it can be used in another editing session. First, visit
the file you want to save the definition in. Then use this command:
M-x insert-kbd-macro <RET> MACRONAME <RET>
This inserts some Lisp code that, when executed later, will define the
same macro with the same definition it has now. (You need not
understand Lisp code to do this, because `insert-kbd-macro' writes the
Lisp code for you.) Then save the file. You can load the file later
with `load-file' (*note Lisp Libraries::.). If the file you save in is
your init file `~/.emacs' (*note Init File::.) then the macro will be
defined each time you run Emacs.
If you give `insert-kbd-macro' a numeric argument, it makes
additional Lisp code to record the keys (if any) that you have bound to
the keyboard macro, so that the macro will be reassigned the same keys
when you load the file.
Executing Macros with Variations
--------------------------------
Using `C-x q' (`kbd-macro-query'), you can get an effect similar to
that of `query-replace', where the macro asks you each time around
whether to make a change. While defining the macro, type `C-x q' at
the point where you want the query to occur. During macro definition,
the `C-x q' does nothing, but when you run the macro later, `C-x q'
asks you interactively whether to continue.
The valid responses when `C-x q' asks are <SPC> (or `y'), <DEL> (or
`n'), <RET> (or `q'), `C-l' and `C-r'. The answers are the same as in
`query-replace', though not all of the `query-replace' options are
meaningful.
These responses include <SPC> to continue, and <DEL> to skip the
remainder of this repetition of the macro and start right away with the
next repetition. <RET> means to skip the remainder of this repetition
and cancel further repetitions. `C-l' redraws the screen and asks you
again for a character to say what to do.
`C-r' enters a recursive editing level, in which you can perform
editing which is not part of the macro. When you exit the recursive
edit using `C-M-c', you are asked again how to continue with the
keyboard macro. If you type a <SPC> at this time, the rest of the
macro definition is executed. It is up to you to leave point and the
text in a state such that the rest of the macro will do what you want.
`C-u C-x q', which is `C-x q' with a numeric argument, performs a
completely different function. It enters a recursive edit reading
input from the keyboard, both when you type it during the definition of
the macro, and when it is executed from the macro. During definition,
the editing you do inside the recursive edit does not become part of
the macro. During macro execution, the recursive edit gives you a
chance to do some particularized editing on each repetition. *Note
Recursive Edit::.
Customizing Key Bindings
========================
This section describes "key bindings", which map keys to commands,
and "keymaps", which record key bindings. It also explains how to
customize key bindings.
Recall that a command is a Lisp function whose definition provides
for interactive use. Like every Lisp function, a command has a function
name which usually consists of lower-case letters and hyphens.
Keymaps
-------
The bindings between key sequences and command functions are recorded
in data structures called "keymaps". Emacs has many of these, each
used on particular occasions.
Recall that a "key sequence" ("key", for short) is a sequence of
"input events" that have a meaning as a unit. Input events include
characters, function keys and mouse buttons--all the inputs that you
can send to the computer with your terminal. A key sequence gets its
meaning from its "binding", which says what command it runs. The
function of keymaps is to record these bindings.
The "global" keymap is the most important keymap because it is
always in effect. The global keymap defines keys for Fundamental mode;
most of these definitions are common to most or all major modes. Each
major or minor mode can have its own keymap which overrides the global
definitions of some keys.
For example, a self-inserting character such as `g' is
self-inserting because the global keymap binds it to the command
`self-insert-command'. The standard Emacs editing characters such as
`C-a' also get their standard meanings from the global keymap.
Commands to rebind keys, such as `M-x global-set-key', actually work by
storing the new binding in the proper place in the global map. *Note
Rebinding::.
Meta characters work differently; Emacs translates each Meta
character into a pair of characters starting with <ESC>. When you type
the character `M-a' in a key sequence, Emacs replaces it with `<ESC>
a'. A meta key comes in as a single input event, but becomes two
events for purposes of key bindings. The reason for this is
historical, and we might change it someday.
Most modern keyboards have function keys as well as character keys.
Function keys send input events just as character keys do, and keymaps
can have bindings for them.
On many terminals, typing a function key actually sends the computer
a sequence of characters; the precise details of the sequence depends on
which function key and on the model of terminal you are using. (Often
the sequence starts with `<ESC> ['.) If Emacs understands your
terminal type properly, it recognizes the character sequences forming
function keys wherever they occur in a key sequence (not just at the
beginning). Thus, for most purposes, you can pretend the function keys
reach Emacs directly and ignore their encoding as character sequences.
Mouse buttons also produce input events. These events come with
other data--the window and position where you pressed or released the
button, and a time stamp. But only the choice of button matters for key
bindings; the other data matters only if a command looks at it.
(Commands designed for mouse invocation usually do look at the other
data.)
A keymap records definitions for single events. Interpreting a key
sequence of multiple events involves a chain of keymaps. The first
keymap gives a definition for the first event; this definition is
another keymap, which is used to look up the second event in the
sequence, and so on.
Key sequences can mix function keys and characters. For example,
`C-x <SELECT>' is meaningful. If you make <SELECT> a prefix key, then
`<SELECT> C-n' makes sense. You can even mix mouse events with
keyboard events, but we recommend against it, because such sequences
are inconvenient to type in.
As a user, you can redefine any key; but it might be best to stick to
key sequences that consist of `C-c' followed by a letter. These keys
are "reserved for users," so they won't conflict with any properly
designed Emacs extension. The function keys <F5> through <F9> are also
reserved for users. If you redefine some other key, your definition
may be overridden by certain extensions or major modes which redefine
the same key.
Prefix Keymaps
--------------
A prefix key such as `C-x' or <ESC> has its own keymap, which holds
the definition for the event that immediately follows that prefix.
The definition of a prefix key is usually the keymap to use for
looking up the following event. The definition can also be a Lisp
symbol whose function definition is the following keymap; the effect is
the same, but it provides a command name for the prefix key that can be
used as a description of what the prefix key is for. Thus, the binding
of `C-x' is the symbol `Ctl-X-Prefix', whose function definition is the
keymap for `C-x' commands. The definitions of `C-c', `C-x', `C-h' and
<ESC> as prefix keys appear in the global map, so these prefix keys are
always available.
Aside from ordinary prefix keys, there is a fictitious "prefix key"
which represents the menu bar; see *Note Menu Bar: (elisp)Menu Bar, for
special information about menu bar key bindings. Mouse button events
that invoke pop-up menus are also prefix keys; see *Note Menu Keymaps:
(elisp)Menu Keymaps, for more details.
Some prefix keymaps are stored in variables with names:
* `ctl-x-map' is the variable name for the map used for characters
that follow `C-x'.
* `help-map' is for characters that follow `C-h'.
* `esc-map' is for characters that follow <ESC>. Thus, all Meta
characters are actually defined by this map.
* `ctl-x-4-map' is for characters that follow `C-x 4'.
* `mode-specific-map' is for characters that follow `C-c'.
Local Keymaps
-------------
So far we have explained the ins and outs of the global map. Major
modes customize Emacs by providing their own key bindings in "local
keymaps". For example, C mode overrides <TAB> to make it indent the
current line for C code. Portions of text in the buffer can specify
their own keymaps to substitute for the keymap of the buffer's major
mode.
Minor modes can also have local keymaps. Whenever a minor mode is
in effect, the definitions in its keymap override both the major mode's
local keymap and the global keymap.
The local keymaps for Lisp mode and several other major modes always
exist even when not in use. These are kept in variables named
`lisp-mode-map' and so on. For major modes less often used, the local
keymap is normally constructed only when the mode is used for the first
time in a session. This is to save space. If you wish to change one
of these keymaps, you must use the major mode's "mode hook"--see below.
All minor mode keymaps are created in advance. There is no way to
defer their creation until the first time the minor mode is enabled.
A local keymap can locally redefine a key as a prefix key by defining
it as a prefix keymap. If the key is also defined globally as a prefix,
then its local and global definitions (both keymaps) effectively
combine: both of them are used to look up the event that follows the
prefix key. Thus, if the mode's local keymap defines `C-c' as another
keymap, and that keymap defines `C-z' as a command, this provides a
local meaning for `C-c C-z'. This does not affect other sequences that
start with `C-c'; if those sequences don't have their own local
bindings, their global bindings remain in effect.
Another way to think of this is that Emacs handles a multi-event key
sequence by looking in several keymaps, one by one, for a binding of the
whole key sequence. First it checks the minor mode keymaps for minor
modes that are enabled, then it checks the major mode's keymap, and then
it checks the global keymap. This is not precisely how key lookup
works, but it's good enough for understanding ordinary circumstances.
To change the local bindings of a major mode, you must change the
mode's local keymap. Normally you must wait until the first time the
mode is used, because most major modes don't create their keymaps until
then. If you want to specify something in your `~/.emacs' file to
change a major mode's bindings, you must use the mode's mode hook to
delay the change until the mode is first used.
For example, the command `texinfo-mode' to select Texinfo mode runs
the hook `texinfo-mode-hook'. Here's how you can use the hook to add
local bindings (not very useful, we admit) for `C-c n' and `C-c p' in
Texinfo mode:
(add-hook 'texinfo-mode-hook
'(lambda ()
(define-key texinfo-mode-map
"\C-cp"
'backward-paragraph)
(define-key texinfo-mode-map
"\C-cn"
'forward-paragraph)
))
*Note Hooks::.
Minibuffer Keymaps
------------------
The minibuffer has its own set of local keymaps; they contain various
completion and exit commands.
* `minibuffer-local-map' is used for ordinary input (no completion).
* `minibuffer-local-ns-map' is similar, except that <SPC> exits just
like <RET>. This is used mainly for Mocklisp compatibility.
* `minibuffer-local-completion-map' is for permissive completion.
* `minibuffer-local-must-match-map' is for strict completion and for
cautious completion.
Changing Key Bindings Interactively
-----------------------------------
The way to redefine an Emacs key is to change its entry in a keymap.
You can change the global keymap, in which case the change is effective
in all major modes (except those that have their own overriding local
definitions for the same key). Or you can change the current buffer's
local map, which affects all buffers using the same major mode.
`M-x global-set-key <RET> KEY CMD <RET>'
Define KEY globally to run CMD.
`M-x local-set-key <RET> KEY CMD <RET>'
Define KEY locally (in the major mode now in effect) to run CMD.
`M-x global-unset-key <RET> KEY'
Make KEY undefined in the global map.
`M-x local-unset-key <RET> KEY'
Make KEY undefined locally (in the major mode now in effect).
For example, suppose you like to execute commands in a subshell
within an Emacs buffer, instead of suspending Emacs and executing
commands in your login shell. Normally, `C-z' is bound to the function
`suspend-emacs' (when not using the X Window System), but you can
change `C-z' to invoke an interactive subshell within Emacs, by binding
it to `shell' as follows:
M-x global-set-key <RET> C-z shell <RET>
`global-set-key' reads the command name after the key. After you
press the key, a message like this appears so that you can confirm that
you are binding the key you want:
Set key C-z to command:
You can redefine function keys and mouse events in the same way; just
type the function key or click the mouse when it's time to specify the
key to rebind.
You can rebind a key that contains more than one event in the same
way. Emacs keeps reading the key to rebind until it is a complete key
(that is, not a prefix key). Thus, if you type `C-f' for KEY, that's
the end; the minibuffer is entered immediately to read CMD. But if you
type `C-x', another character is read; if that is `4', another
character is read, and so on. For example,
M-x global-set-key <RET> C-x 4 $ spell-other-window <RET>
redefines `C-x 4 $' to run the (fictitious) command
`spell-other-window'.
The two-character keys consisting of `C-c' followed by a letter are
reserved for user customizations. Lisp programs are not supposed to
define these keys, so the bindings you make for them will be available
in all major modes and will never get in the way of anything.
You can remove the global definition of a key with
`global-unset-key'. This makes the key "undefined"; if you type it,
Emacs will just beep. Similarly, `local-unset-key' makes a key
undefined in the current major mode keymap, which makes the global
definition (or lack of one) come back into effect in that major mode.
If you have redefined (or undefined) a key and you subsequently wish
to retract the change, undefining the key will not do the job--you need
to redefine the key with its standard definition. To find the name of
the standard definition of a key, go to a Fundamental mode buffer and
use `C-h c'. The documentation of keys in this manual also lists their
command names.
If you want to prevent yourself from invoking a command by mistake,
it is better to disable the command than to undefine the key. A
disabled command is less work to invoke when you really want to. *Note
Disabling::.
Rebinding Keys in Your Init File
--------------------------------
If you have a set of key bindings that you like to use all the time,
you can specify them in your `.emacs' file by using their Lisp syntax.
The simplest method for doing this works for ASCII characters and
Meta-modified ASCII characters only. This method uses a string to
represent the key sequence you want to rebind. For example, here's how
to bind `C-z' to `shell':
(global-set-key "\C-z" 'shell)
This example uses a string constant containing one character, `C-z'.
The single-quote before the command name, `shell', marks it as a
constant symbol rather than a variable. If you omit the quote, Emacs
would try to evaluate `shell' immediately as a variable. This probably
causes an error; it certainly isn't what you want.
Here is another example that binds a key sequence two characters
long:
(global-set-key "\C-xl" 'make-symbolic-link)
When the key sequence includes function keys or mouse button events,
or non-ASCII characters such as `C-=' or `H-a', you must use the more
general method of rebinding, which uses a vector to specify the key
sequence.
The way to write a vector in Emacs Lisp is with square brackets
around the vector elements. Use spaces to separate the elements. If an
element is a symbol, simply write the symbol's name--no other
delimiters or punctuation are needed. If a vector element is a
character, write it as a Lisp character constant: `?' followed by the
character as it would appear in a string.
Here are examples of using vectors to rebind `C-=' (a control
character outside of ASCII), `H-a' (a Hyper character; ASCII doesn't
have Hyper at all), <F7> (a function key), and `C-Mouse-1' (a
keyboard-modified mouse button):
(global-set-key [?\C-=] 'make-symbolic-link)
(global-set-key [?\H-a] 'make-symbolic-link)
(global-set-key [f7] 'make-symbolic-link)
(global-set-key [C-mouse-1] 'make-symbolic-link)
You can use a vector for the simple cases too. Here's how to rewrite
the first two examples, above, to use vectors:
(global-set-key [?\C-z] 'shell)
(global-set-key [?\C-x ?l] 'make-symbolic-link)
Rebinding Function Keys
-----------------------
Key sequences can contain function keys as well as ordinary
characters. Just as Lisp characters (actually integers) represent
keyboard characters, Lisp symbols represent function keys. If the
function key has a word as its label, then that word is also the name of
the corresponding Lisp symbol. Here are the conventional Lisp names for
common function keys:
`left', `up', `right', `down'
Cursor arrow keys.
`begin', `end', `home', `next', `prior'
Other cursor repositioning keys.
`select', `print', `execute', `backtab'
`insert', `undo', `redo', `clearline'
`insertline', `deleteline', `insertchar', `deletechar',
Miscellaneous function keys.
`f1', `f2', ... `f35'
Numbered function keys (across the top of the keyboard).
`kp-add', `kp-subtract', `kp-multiply', `kp-divide'
`kp-backtab', `kp-space', `kp-tab', `kp-enter'
`kp-separator', `kp-decimal', `kp-equal'
Keypad keys (to the right of the regular keyboard), with names or
punctuation.
`kp-0', `kp-1', ... `kp-9'
Keypad keys with digits.
`kp-f1', `kp-f2', `kp-f3', `kp-f4'
Keypad PF keys.
These names are conventional, but some systems (especially when using
X windows) may use different names. To make certain what symbol is used
for a given function key on your terminal, type `C-h c' followed by
that key.
A key sequence which contains function key symbols (or anything but
ASCII characters) must be a vector rather than a string. The vector
syntax uses spaces between the elements, and square brackets around the
whole vector. Thus, to bind function key `f1' to the command `rmail',
write the following:
(global-set-key [f1] 'rmail)
To bind the right-arrow key to the command `forward-char', you can use
this expression:
(global-set-key [right] 'forward-char)
This uses the Lisp syntax for a vector containing the symbol `right'.
(This binding is present in Emacs by default.)
*Note Init Rebinding::, for more information about using vectors for
rebinding.
You can mix function keys and characters in a key sequence. This
example binds `C-x <NEXT>' to the command `forward-page'.
(global-set-key [?\C-x next] 'forward-page)
where `?\C-x' is the Lisp character constant for the character `C-x'.
The vector element `next' is a symbol and therefore does not take a
question mark.
You can use the modifier keys <CTRL>, <META>, <HYPER>, <SUPER>,
<ALT> and <SHIFT> with function keys. To represent these modifiers,
add the strings `C-', `M-', `H-', `s-', `A-' and `S-' at the front of
the symbol name. Thus, here is how to make `Hyper-Meta-<RIGHT>' move
forward a word:
(global-set-key [H-M-right] 'forward-word)
Named ASCII Control Characters
------------------------------
<TAB>, <RET>, <BS>, <LFD>, <ESC> and <DEL> started out as names for
certain ASCII control characters, used so often that they have special
keys of their own. Later, users found it convenient to distinguish in
Emacs between these keys and the "same" control characters typed with
the <CTRL> key.
Emacs distinguishes these two kinds of input, when used with the X
Window System. It treats the "special" keys as function keys named
`tab', `return', `backspace', `linefeed', `escape', and `delete'.
These function keys translate automatically into the corresponding
ASCII characters *if* they have no bindings of their own. As a result,
neither users nor Lisp programs need to pay attention to the
distinction unless they care to.
If you do not want to distinguish between (for example) <TAB> and
`C-i', make just one binding, for the ASCII character <TAB> (octal code
011). If you do want to distinguish, make one binding for this ASCII
character, and another for the "function key" `tab'.
With an ordinary ASCII terminal, there is no way to distinguish
between <TAB> and `C-i' (and likewise for other such pairs), because
the terminal sends the same character in both cases.
Non-ASCII Characters on the Keyboard
------------------------------------
If your keyboard has keys that send non-ASCII characters, such as
accented letters, rebinding these keys is a bit tricky. There are two
solutions you can use. One is to specify a keyboard coding system,
using `set-keyboard-coding-system' (*note Specify Coding::.). Then you
can bind these keys in the usual way, but writing
(global-set-key [?CHAR] 'some-function)
and typing the key you want to bind to insert CHAR.
If you don't specify the keyboard coding system, that approach won't
work. Instead, you need to find out the actual code that the terminal
sends. The easiest way to do this in Emacs is to create an empty buffer
with `C-x b temp <RET>', make it unibyte with `M-x
toggle-enable-multibyte-characters <RET>', then type the key to insert
the character into this buffer.
Move point before the character, then type `C-b C-x ='. This
displays a message in the minibuffer, showing the character code in
three ways, octal, decimal and hexadecimal, all within a set of
parentheses. Use the second of the three numbers, the decimal one,
inside the vector to bind:
(global-set-key [DECIMAL-CODE] 'some-function)
Rebinding Mouse Buttons
-----------------------
Emacs uses Lisp symbols to designate mouse buttons, too. The
ordinary mouse events in Emacs are "click" events; these happen when you
press a button and release it without moving the mouse. You can also
get "drag" events, when you move the mouse while holding the button
down. Drag events happen when you finally let go of the button.
The symbols for basic click events are `mouse-1' for the leftmost
button, `mouse-2' for the next, and so on. Here is how you can
redefine the second mouse button to split the current window:
(global-set-key [mouse-2] 'split-window-vertically)
The symbols for drag events are similar, but have the prefix `drag-'
before the word `mouse'. For example, dragging the first button
generates a `drag-mouse-1' event.
You can also define bindings for events that occur when a mouse
button is pressed down. These events start with `down-' instead of
`drag-'. Such events are generated only if they have key bindings.
When you get a button-down event, a corresponding click or drag event
will always follow.
If you wish, you can distinguish single, double, and triple clicks.
A double click means clicking a mouse button twice in approximately the
same place. The first click generates an ordinary click event. The
second click, if it comes soon enough, generates a double-click event
instead. The event type for a double-click event starts with
`double-': for example, `double-mouse-3'.
This means that you can give a special meaning to the second click at
the same place, but it must act on the assumption that the ordinary
single click definition has run when the first click was received.
This constrains what you can do with double clicks, but user
interface designers say that this constraint ought to be followed in
any case. A double click should do something similar to the single
click, only "more so." The command for the double-click event should
perform the extra work for the double click.
If a double-click event has no binding, it changes to the
corresponding single-click event. Thus, if you don't define a
particular double click specially, it executes the single-click command
twice.
Emacs also supports triple-click events whose names start with
`triple-'. Emacs does not distinguish quadruple clicks as event types;
clicks beyond the third generate additional triple-click events.
However, the full number of clicks is recorded in the event list, so you
can distinguish if you really want to. We don't recommend distinct
meanings for more than three clicks, but sometimes it is useful for
subsequent clicks to cycle through the same set of three meanings, so
that four clicks are equivalent to one click, five are equivalent to
two, and six are equivalent to three.
Emacs also records multiple presses in drag and button-down events.
For example, when you press a button twice, then move the mouse while
holding the button, Emacs gets a `double-drag-' event. And at the
moment when you press it down for the second time, Emacs gets a
`double-down-' event (which is ignored, like all button-down events, if
it has no binding).
The variable `double-click-time' specifies how long may elapse
between clicks that are recognized as a pair. Its value is measured in
milliseconds. If the value is `nil', double clicks are not detected at
all. If the value is `t', then there is no time limit.
The symbols for mouse events also indicate the status of the modifier
keys, with the usual prefixes `C-', `M-', `H-', `s-', `A-' and `S-'.
These always precede `double-' or `triple-', which always precede
`drag-' or `down-'.
A frame includes areas that don't show text from the buffer, such as
the mode line and the scroll bar. You can tell whether a mouse button
comes from a special area of the screen by means of dummy "prefix
keys." For example, if you click the mouse in the mode line, you get
the prefix key `mode-line' before the ordinary mouse-button symbol.
Thus, here is how to define the command for clicking the first button in
a mode line to run `scroll-up':
(global-set-key [mode-line mouse-1] 'scroll-up)
Here is the complete list of these dummy prefix keys and their
meanings:
`mode-line'
The mouse was in the mode line of a window.
`vertical-line'
The mouse was in the vertical line separating side-by-side
windows. (If you use scroll bars, they appear in place of these
vertical lines.)
`vertical-scroll-bar'
The mouse was in a vertical scroll bar. (This is the only kind of
scroll bar Emacs currently supports.)
You can put more than one mouse button in a key sequence, but it
isn't usual to do so.
Disabling Commands
------------------
Disabling a command marks the command as requiring confirmation
before it can be executed. The purpose of disabling a command is to
prevent beginning users from executing it by accident and being
confused.
An attempt to invoke a disabled command interactively in Emacs
displays a window containing the command's name, its documentation, and
some instructions on what to do immediately; then Emacs asks for input
saying whether to execute the command as requested, enable it and
execute it, or cancel. If you decide to enable the command, you are
asked whether to do this permanently or just for the current session.
Enabling permanently works by automatically editing your `.emacs' file.
The direct mechanism for disabling a command is to put a non-`nil'
`disabled' property on the Lisp symbol for the command. Here is the
Lisp program to do this:
(put 'delete-region 'disabled t)
If the value of the `disabled' property is a string, that string is
included in the message printed when the command is used:
(put 'delete-region 'disabled
"It's better to use `kill-region' instead.\n")
You can make a command disabled either by editing the `.emacs' file
directly or with the command `M-x disable-command', which edits the
`.emacs' file for you. Likewise, `M-x enable-command' edits `.emacs'
to enable a command permanently. *Note Init File::.
Whether a command is disabled is independent of what key is used to
invoke it; disabling also applies if the command is invoked using
`M-x'. Disabling a command has no effect on calling it as a function
from Lisp programs.
Keyboard Translations
=====================
Some keyboards do not make it convenient to send all the special
characters that Emacs uses. The most common problem case is the <DEL>
character. Some keyboards provide no convenient way to type this very
important character--usually because they were designed to expect the
character `C-h' to be used for deletion. On these keyboards, if you
press the key normally used for deletion, Emacs handles the `C-h' as a
prefix character and offers you a list of help options, which is not
what you want.
You can work around this problem within Emacs by setting up keyboard
translations to turn `C-h' into <DEL> and <DEL> into `C-h', as follows:
;; Translate `C-h' to <DEL>.
(keyboard-translate ?\C-h ?\C-?)
;; Translate <DEL> to `C-h'.
(keyboard-translate ?\C-? ?\C-h)
Keyboard translations are not the same as key bindings in keymaps
(*note Keymaps::.). Emacs contains numerous keymaps that apply in
different situations, but there is only one set of keyboard
translations, and it applies to every character that Emacs reads from
the terminal. Keyboard translations take place at the lowest level of
input processing; the keys that are looked up in keymaps contain the
characters that result from keyboard translation.
Under X, the keyboard key named <DELETE> is a function key and is
distinct from the ASCII character named <DEL>. *Note Named ASCII
Chars::. Keyboard translations affect only ASCII character input, not
function keys; thus, the above example used under X does not affect the
<DELETE> key. However, the translation above isn't necessary under X,
because Emacs can also distinguish between the <BACKSPACE> key and
`C-h'; and it normally treats <BACKSPACE> as <DEL>.
For full information about how to use keyboard translations, see
*Note Translating Input: (elisp)Translating Input.
The Syntax Table
================
All the Emacs commands which parse words or balance parentheses are
controlled by the "syntax table". The syntax table says which
characters are opening delimiters, which are parts of words, which are
string quotes, and so on. Each major mode has its own syntax table
(though sometimes related major modes use the same one) which it
installs in each buffer that uses that major mode. The syntax table
installed in the current buffer is the one that all commands use, so we
call it "the" syntax table. A syntax table is a Lisp object, a
char-table, whose elements are numbers.
To display a description of the contents of the current syntax table,
type `C-h s' (`describe-syntax'). The description of each character
includes both the string you would have to give to
`modify-syntax-entry' to set up that character's current syntax, and
some English to explain that string if necessary.
For full information on the syntax table, see *Note Syntax Tables:
(elisp)Syntax Tables.
The Init File, `~/.emacs'
=========================
When Emacs is started, it normally loads a Lisp program from the file
`.emacs' or `.emacs.el' in your home directory. We call this file your
"init file" because it specifies how to initialize Emacs for you. You
can use the command line switch `-q' to prevent loading your init file,
and `-u' (or `--user') to specify a different user's init file (*note
Entering Emacs::.).
There can also be a "default init file", which is the library named
`default.el', found via the standard search path for libraries. The
Emacs distribution contains no such library; your site may create one
for local customizations. If this library exists, it is loaded
whenever you start Emacs (except when you specify `-q'). But your init
file, if any, is loaded first; if it sets `inhibit-default-init'
non-`nil', then `default' is not loaded.
Your site may also have a "site startup file"; this is named
`site-start.el', if it exists. Emacs loads this library before it
loads your init file. To inhibit loading of this library, use the
option `-no-site-file'.
If you have a large amount of code in your `.emacs' file, you should
rename it to `~/.emacs.el', and byte-compile it. *Note Byte
Compilation: (elisp)Byte Compilation, for more information about
compiling Emacs Lisp programs.
If you are going to write actual Emacs Lisp programs that go beyond
minor customization, you should read the `Emacs Lisp Reference Manual'.
*Note Emacs Lisp: (elisp)Top.
Init File Syntax
----------------
The `.emacs' file contains one or more Lisp function call
expressions. Each of these consists of a function name followed by
arguments, all surrounded by parentheses. For example, `(setq
fill-column 60)' calls the function `setq' to set the variable
`fill-column' (*note Filling::.) to 60.
The second argument to `setq' is an expression for the new value of
the variable. This can be a constant, a variable, or a function call
expression. In `.emacs', constants are used most of the time. They
can be:
Numbers:
Numbers are written in decimal, with an optional initial minus
sign.
Strings:
Lisp string syntax is the same as C string syntax with a few extra
features. Use a double-quote character to begin and end a string
constant.
In a string, you can include newlines and special characters
literally. But often it is cleaner to use backslash sequences for
them: `\n' for newline, `\b' for backspace, `\r' for carriage
return, `\t' for tab, `\f' for formfeed (control-L), `\e' for
escape, `\\' for a backslash, `\"' for a double-quote, or `\OOO'
for the character whose octal code is OOO. Backslash and
double-quote are the only characters for which backslash sequences
are mandatory.
`\C-' can be used as a prefix for a control character, as in
`\C-s' for ASCII control-S, and `\M-' can be used as a prefix for
a Meta character, as in `\M-a' for `Meta-A' or `\M-\C-a' for
`Control-Meta-A'.
Characters:
Lisp character constant syntax consists of a `?' followed by
either a character or an escape sequence starting with `\'.
Examples: `?x', `?\n', `?\"', `?\)'. Note that strings and
characters are not interchangeable in Lisp; some contexts require
one and some contexts require the other.
True:
`t' stands for `true'.
False:
`nil' stands for `false'.
Other Lisp objects:
Write a single-quote (') followed by the Lisp object you want.
Init File Examples
------------------
Here are some examples of doing certain commonly desired things with
Lisp expressions:
* Make <TAB> in C mode just insert a tab if point is in the middle
of a line.
(setq c-tab-always-indent nil)
Here we have a variable whose value is normally `t' for `true' and
the alternative is `nil' for `false'.
* Make searches case sensitive by default (in all buffers that do not
override this).
(setq-default case-fold-search nil)
This sets the default value, which is effective in all buffers
that do not have local values for the variable. Setting
`case-fold-search' with `setq' affects only the current buffer's
local value, which is not what you probably want to do in an init
file.
* Specify your own email address, if Emacs can't figure it out
correctly.
(setq user-mail-address "coon@yoyodyne.com")
Various Emacs packages that need your own email address use the
value of `user-mail-address'.
* Make Text mode the default mode for new buffers.
(setq default-major-mode 'text-mode)
Note that `text-mode' is used because it is the command for
entering Text mode. The single-quote before it makes the symbol a
constant; otherwise, `text-mode' would be treated as a variable
name.
* Set up defaults for the Latin-1 character set which supports most
of the languages of Western Europe.
(set-language-environment "Latin-1")
* Turn on Auto Fill mode automatically in Text mode and related
modes.
(add-hook 'text-mode-hook
'(lambda () (auto-fill-mode 1)))
This shows how to add a hook function to a normal hook variable
(*note Hooks::.). The function we supply is a list starting with
`lambda', with a single-quote in front of it to make it a list
constant rather than an expression.
It's beyond the scope of this manual to explain Lisp functions,
but for this example it is enough to know that the effect is to
execute `(auto-fill-mode 1)' when Text mode is entered. You can
replace that with any other expression that you like, or with
several expressions in a row.
Emacs comes with a function named `turn-on-auto-fill' whose
definition is `(lambda () (auto-fill-mode 1))'. Thus, a simpler
way to write the above example is as follows:
(add-hook 'text-mode-hook 'turn-on-auto-fill)
* Load the installed Lisp library named `foo' (actually a file
`foo.elc' or `foo.el' in a standard Emacs directory).
(load "foo")
When the argument to `load' is a relative file name, not starting
with `/' or `~', `load' searches the directories in `load-path'
(*note Lisp Libraries::.).
* Load the compiled Lisp file `foo.elc' from your home directory.
(load "~/foo.elc")
Here an absolute file name is used, so no searching is done.
* Rebind the key `C-x l' to run the function `make-symbolic-link'.
(global-set-key "\C-xl" 'make-symbolic-link)
or
(define-key global-map "\C-xl" 'make-symbolic-link)
Note once again the single-quote used to refer to the symbol
`make-symbolic-link' instead of its value as a variable.
* Do the same thing for Lisp mode only.
(define-key lisp-mode-map "\C-xl" 'make-symbolic-link)
* Redefine all keys which now run `next-line' in Fundamental mode so
that they run `forward-line' instead.
(substitute-key-definition 'next-line 'forward-line
global-map)
* Make `C-x C-v' undefined.
(global-unset-key "\C-x\C-v")
One reason to undefine a key is so that you can make it a prefix.
Simply defining `C-x C-v ANYTHING' will make `C-x C-v' a prefix,
but `C-x C-v' must first be freed of its usual non-prefix
definition.
* Make `$' have the syntax of punctuation in Text mode. Note the
use of a character constant for `$'.
(modify-syntax-entry ?\$ "." text-mode-syntax-table)
* Enable the use of the command `narrow-to-region' without
confirmation.
(put 'narrow-to-region 'disabled nil)
Terminal-specific Initialization
--------------------------------
Each terminal type can have a Lisp library to be loaded into Emacs
when it is run on that type of terminal. For a terminal type named
TERMTYPE, the library is called `term/TERMTYPE' and it is found by
searching the directories `load-path' as usual and trying the suffixes
`.elc' and `.el'. Normally it appears in the subdirectory `term' of
the directory where most Emacs libraries are kept.
The usual purpose of the terminal-specific library is to map the
escape sequences used by the terminal's function keys onto more
meaningful names, using `function-key-map'. See the file
`term/lk201.el' for an example of how this is done. Many function keys
are mapped automatically according to the information in the Termcap
data base; the terminal-specific library needs to map only the function
keys that Termcap does not specify.
When the terminal type contains a hyphen, only the part of the name
before the first hyphen is significant in choosing the library name.
Thus, terminal types `aaa-48' and `aaa-30-rv' both use the library
`term/aaa'. The code in the library can use `(getenv "TERM")' to find
the full terminal type name.
The library's name is constructed by concatenating the value of the
variable `term-file-prefix' and the terminal type. Your `.emacs' file
can prevent the loading of the terminal-specific library by setting
`term-file-prefix' to `nil'.
Emacs runs the hook `term-setup-hook' at the end of initialization,
after both your `.emacs' file and any terminal-specific library have
been read in. Add hook functions to this hook if you wish to override
part of any of the terminal-specific libraries and to define
initializations for terminals that do not have a library. *Note
Hooks::.
How Emacs Finds Your Init File
------------------------------
Normally Emacs uses the environment variable `HOME' to find
`.emacs'; that's what `~' means in a file name. But if you have done
`su', Emacs tries to find your own `.emacs', not that of the user you
are currently pretending to be. The idea is that you should get your
own editor customizations even if you are running as the super user.
More precisely, Emacs first determines which user's init file to use.
It gets the user name from the environment variables `LOGNAME' and
`USER'; if neither of those exists, it uses effective user-ID. If that
user name matches the real user-ID, then Emacs uses `HOME'; otherwise,
it looks up the home directory corresponding to that user name in the
system's data base of users.
Quitting and Aborting
=====================
`C-g'
`C-<BREAK> (MS-DOS)'
Quit. Cancel running or partially typed command.
`C-]'
Abort innermost recursive editing level and cancel the command
which invoked it (`abort-recursive-edit').
`<ESC> <ESC> <ESC>'
Either quit or abort, whichever makes sense
(`keyboard-escape-quit').
`M-x top-level'
Abort all recursive editing levels that are currently executing.
`C-x u'
Cancel a previously made change in the buffer contents (`undo').
There are two ways of canceling commands which are not finished
executing: "quitting" with `C-g', and "aborting" with `C-]' or `M-x
top-level'. Quitting cancels a partially typed command or one which is
already running. Aborting exits a recursive editing level and cancels
the command that invoked the recursive edit. (*Note Recursive Edit::.)
Quitting with `C-g' is used for getting rid of a partially typed
command, or a numeric argument that you don't want. It also stops a
running command in the middle in a relatively safe way, so you can use
it if you accidentally give a command which takes a long time. In
particular, it is safe to quit out of killing; either your text will
*all* still be in the buffer, or it will *all* be in the kill ring (or
maybe both). Quitting an incremental search does special things
documented under searching; in general, it may take two successive
`C-g' characters to get out of a search (*note Incremental Search::.).
On MS-DOS, the character `C-<BREAK>' serves as a quit character like
`C-g'. The reason is that it is not feasible, on MS-DOS, to recognize
`C-g' while a command is running, between interactions with the user.
By contrast, it *is* feasible to recognize `C-<BREAK>' at all times.
*Note MS-DOS Input::.
`C-g' works by setting the variable `quit-flag' to `t' the instant
`C-g' is typed; Emacs Lisp checks this variable frequently and quits if
it is non-`nil'. `C-g' is only actually executed as a command if you
type it while Emacs is waiting for input.
If you quit with `C-g' a second time before the first `C-g' is
recognized, you activate the "emergency escape" feature and return to
the shell. *Note Emergency Escape::.
There may be times when you cannot quit. When Emacs is waiting for
the operating system to do something, quitting is impossible unless
special pains are taken for the particular system call within Emacs
where the waiting occurs. We have done this for the system calls that
users are likely to want to quit from, but it's possible you will find
another. In one very common case--waiting for file input or output
using NFS--Emacs itself knows how to quit, but most NFS implementations
simply do not allow user programs to stop waiting for NFS when the NFS
server is hung.
Aborting with `C-]' (`abort-recursive-edit') is used to get out of a
recursive editing level and cancel the command which invoked it.
Quitting with `C-g' does not do this, and could not do this, because it
is used to cancel a partially typed command *within* the recursive
editing level. Both operations are useful. For example, if you are in
a recursive edit and type `C-u 8' to enter a numeric argument, you can
cancel that argument with `C-g' and remain in the recursive edit.
The command `<ESC> <ESC> <ESC>' (`keyboard-escape-quit') can either
quit or abort. This key was defined because <ESC> is used to "get out"
in many PC programs. It can cancel a prefix argument, clear a selected
region, or get out of a Query Replace, like `C-g'. It can get out of
the minibuffer or a recursive edit, like `C-]'. It can also get out of
splitting the frame into multiple windows, like `C-x 1'. One thing it
cannot do, however, is stop a command that is running. That's because
it executes as an ordinary command, and Emacs doesn't notice it until
it is ready for a command.
The command `M-x top-level' is equivalent to "enough" `C-]' commands
to get you out of all the levels of recursive edits that you are in.
`C-]' gets you out one level at a time, but `M-x top-level' goes out
all levels at once. Both `C-]' and `M-x top-level' are like all other
commands, and unlike `C-g', in that they take effect only when Emacs is
ready for a command. `C-]' is an ordinary key and has its meaning only
because of its binding in the keymap. *Note Recursive Edit::.
`C-x u' (`undo') is not strictly speaking a way of canceling a
command, but you can think of it as canceling a command that already
finished executing. *Note Undo::.
Dealing with Emacs Trouble
==========================
This section describes various conditions in which Emacs fails to
work normally, and how to recognize them and correct them.
If <DEL> Fails to Delete
------------------------
If you find that <DEL> enters Help like `Control-h' instead of
deleting a character, your terminal is sending the wrong code for
<DEL>. You can work around this problem by changing the keyboard
translation table (*note Keyboard Translations::.).
Recursive Editing Levels
------------------------
Recursive editing levels are important and useful features of Emacs,
but they can seem like malfunctions to the user who does not understand
them.
If the mode line has square brackets `[...]' around the parentheses
that contain the names of the major and minor modes, you have entered a
recursive editing level. If you did not do this on purpose, or if you
don't understand what that means, you should just get out of the
recursive editing level. To do so, type `M-x top-level'. This is
called getting back to top level. *Note Recursive Edit::.
Garbage on the Screen
---------------------
If the data on the screen looks wrong, the first thing to do is see
whether the text is really wrong. Type `C-l', to redisplay the entire
screen. If the screen appears correct after this, the problem was
entirely in the previous screen update. (Otherwise, see *Note Text
Garbled::.)
Display updating problems often result from an incorrect termcap
entry for the terminal you are using. The file `etc/TERMS' in the Emacs
distribution gives the fixes for known problems of this sort.
`INSTALL' contains general advice for these problems in one of its
sections. Very likely there is simply insufficient padding for certain
display operations. To investigate the possibility that you have this
sort of problem, try Emacs on another terminal made by a different
manufacturer. If problems happen frequently on one kind of terminal
but not another kind, it is likely to be a bad termcap entry, though it
could also be due to a bug in Emacs that appears for terminals that
have or that lack specific features.
Garbage in the Text
-------------------
If `C-l' shows that the text is wrong, try undoing the changes to it
using `C-x u' until it gets back to a state you consider correct. Also
try `C-h l' to find out what command you typed to produce the observed
results.
If a large portion of text appears to be missing at the beginning or
end of the buffer, check for the word `Narrow' in the mode line. If it
appears, the text you don't see is probably still present, but
temporarily off-limits. To make it accessible again, type `C-x n w'.
*Note Narrowing::.
Spontaneous Entry to Incremental Search
---------------------------------------
If Emacs spontaneously displays `I-search:' at the bottom of the
screen, it means that the terminal is sending `C-s' and `C-q' according
to the poorly designed xon/xoff "flow control" protocol.
If this happens to you, your best recourse is to put the terminal in
a mode where it will not use flow control, or give it so much padding
that it will never send a `C-s'. (One way to increase the amount of
padding is to set the variable `baud-rate' to a larger value. Its
value is the terminal output speed, measured in the conventional units
of baud.)
If you don't succeed in turning off flow control, the next best thing
is to tell Emacs to cope with it. To do this, call the function
`enable-flow-control'.
Typically there are particular terminal types with which you must use
flow control. You can conveniently ask for flow control on those
terminal types only, using `enable-flow-control-on'. For example, if
you find you must use flow control on VT-100 and H19 terminals, put the
following in your `.emacs' file:
(enable-flow-control-on "vt100" "h19")
When flow control is enabled, you must type `C-\' to get the effect
of a `C-s', and type `C-^' to get the effect of a `C-q'. (These
aliases work by means of keyboard translations; see *Note Keyboard
Translations::.)
Running out of Memory
---------------------
If you get the error message `Virtual memory exceeded', save your
modified buffers with `C-x s'. This method of saving them has the
smallest need for additional memory. Emacs keeps a reserve of memory
which it makes available when this error happens; that should be enough
to enable `C-x s' to complete its work.
Once you have saved your modified buffers, you can exit this Emacs
job and start another, or you can use `M-x kill-some-buffers' to free
space in the current Emacs job. If you kill buffers containing a
substantial amount of text, you can safely go on editing. Emacs refills
its memory reserve automatically when it sees sufficient free space
available, in case you run out of memory another time.
Do not use `M-x buffer-menu' to save or kill buffers when you run
out of memory, because the buffer menu needs a fair amount memory
itself, and the reserve supply may not be enough.
Recovery After a Crash
----------------------
If Emacs or the computer crashes, you can recover the files you were
editing at the time of the crash from their auto-save files. To do
this, start Emacs again and type the command `M-x recover-session'.
This command initially displays a buffer which lists interrupted
session files, each with its date. You must choose which session to
recover from. Typically the one you want is the most recent one. Move
point to the one you choose, and type `C-c C-c'.
Then `recover-session' asks about each of the files that you were
editing during that session; it asks whether to recover that file. If
you answer `y' for a file, it shows the dates of that file and its
auto-save file, then asks once again whether to recover that file. For
the second question, you must confirm with `yes'. If you do, Emacs
visits the file but gets the text from the auto-save file.
When `recover-session' is done, the files you've chosen to recover
are present in Emacs buffers. You should then save them. Only
this--saving them--updates the files themselves.
Emergency Escape
----------------
Because at times there have been bugs causing Emacs to loop without
checking `quit-flag', a special feature causes Emacs to be suspended
immediately if you type a second `C-g' while the flag is already set,
so you can always get out of GNU Emacs. Normally Emacs recognizes and
clears `quit-flag' (and quits!) quickly enough to prevent this from
happening. (On MS-DOS and compatible systems, type `C-<BREAK>' twice.)
When you resume Emacs after a suspension caused by multiple `C-g', it
asks two questions before going back to what it had been doing:
Auto-save? (y or n)
Abort (and dump core)? (y or n)
Answer each one with `y' or `n' followed by <RET>.
Saying `y' to `Auto-save?' causes immediate auto-saving of all
modified buffers in which auto-saving is enabled.
Saying `y' to `Abort (and dump core)?' causes an illegal instruction
to be executed, dumping core. This is to enable a wizard to figure out
why Emacs was failing to quit in the first place. Execution does not
continue after a core dump. If you answer `n', execution does
continue. With luck, GNU Emacs will ultimately check `quit-flag' and
quit normally. If not, and you type another `C-g', it is suspended
again.
If Emacs is not really hung, just slow, you may invoke the double
`C-g' feature without really meaning to. Then just resume and answer
`n' to both questions, and you will arrive at your former state.
Presumably the quit you requested will happen soon.
The double-`C-g' feature is turned off when Emacs is running under
the X Window System, since you can use the window manager to kill Emacs
or to create another window and run another program.
On MS-DOS and compatible systems, the emergency escape feature is
sometimes unavailable, even if you press `C-<BREAK>' twice, when some
system call (MS-DOS or BIOS) hangs, or when Emacs is stuck in a very
tight endless loop (in C code, *not* in Lisp code).
Help for Total Frustration
--------------------------
If using Emacs (or something else) becomes terribly frustrating and
none of the techniques described above solve the problem, Emacs can
still help you.
First, if the Emacs you are using is not responding to commands, type
`C-g C-g' to get out of it and then start a new one.
Second, type `M-x doctor <RET>'.
The doctor will help you feel better. Each time you say something to
the doctor, you must end it by typing <RET> <RET>. This lets the
doctor know you are finished.
Reporting Bugs
==============
Sometimes you will encounter a bug in Emacs. Although we cannot
promise we can or will fix the bug, and we might not even agree that it
is a bug, we want to hear about problems you encounter. Often we agree
they are bugs and want to fix them.
To make it possible for us to fix a bug, you must report it. In
order to do so effectively, you must know when and how to do it.
When Is There a Bug
-------------------
If Emacs executes an illegal instruction, or dies with an operating
system error message that indicates a problem in the program (as
opposed to something like "disk full"), then it is certainly a bug.
If Emacs updates the display in a way that does not correspond to
what is in the buffer, then it is certainly a bug. If a command seems
to do the wrong thing but the problem corrects itself if you type
`C-l', it is a case of incorrect display updating.
Taking forever to complete a command can be a bug, but you must make
certain that it was really Emacs's fault. Some commands simply take a
long time. Type `C-g' (`C-<BREAK>' on MS-DOS) and then `C-h l' to see
whether the input Emacs received was what you intended to type; if the
input was such that you *know* it should have been processed quickly,
report a bug. If you don't know whether the command should take a long
time, find out by looking in the manual or by asking for assistance.
If a command you are familiar with causes an Emacs error message in a
case where its usual definition ought to be reasonable, it is probably a
bug.
If a command does the wrong thing, that is a bug. But be sure you
know for certain what it ought to have done. If you aren't familiar
with the command, or don't know for certain how the command is supposed
to work, then it might actually be working right. Rather than jumping
to conclusions, show the problem to someone who knows for certain.
Finally, a command's intended definition may not be best for editing
with. This is a very important sort of problem, but it is also a
matter of judgment. Also, it is easy to come to such a conclusion out
of ignorance of some of the existing features. It is probably best not
to complain about such a problem until you have checked the
documentation in the usual ways, feel confident that you understand it,
and know for certain that what you want is not available. If you are
not sure what the command is supposed to do after a careful reading of
the manual, check the index and glossary for any terms that may be
unclear.
If after careful rereading of the manual you still do not understand
what the command should do, that indicates a bug in the manual, which
you should report. The manual's job is to make everything clear to
people who are not Emacs experts--including you. It is just as
important to report documentation bugs as program bugs.
If the on-line documentation string of a function or variable
disagrees with the manual, one of them must be wrong; that is a bug.
Understanding Bug Reporting
---------------------------
When you decide that there is a bug, it is important to report it
and to report it in a way which is useful. What is most useful is an
exact description of what commands you type, starting with the shell
command to run Emacs, until the problem happens.
The most important principle in reporting a bug is to report
*facts*. Hypotheses and verbal descriptions are no substitute for the
detailed raw data. Reporting the facts is straightforward, but many
people strain to posit explanations and report them instead of the
facts. If the explanations are based on guesses about how Emacs is
implemented, they will be useless; meanwhile, lacking the facts, we will
have no real information about the bug.
For example, suppose that you type `C-x C-f /glorp/baz.ugh <RET>',
visiting a file which (you know) happens to be rather large, and Emacs
displayed `I feel pretty today'. The best way to report the bug is
with a sentence like the preceding one, because it gives all the facts.
A bad way would be to assume that the problem is due to the size of
the file and say, "I visited a large file, and Emacs displayed `I feel
pretty today'." This is what we mean by "guessing explanations." The
problem is just as likely to be due to the fact that there is a `z' in
the file name. If this is so, then when we got your report, we would
try out the problem with some "large file," probably with no `z' in its
name, and not see any problem. There is no way in the world that we
could guess that we should try visiting a file with a `z' in its name.
Alternatively, the problem might be due to the fact that the file
starts with exactly 25 spaces. For this reason, you should make sure
that you inform us of the exact contents of any file that is needed to
reproduce the bug. What if the problem only occurs when you have typed
the `C-x C-a' command previously? This is why we ask you to give the
exact sequence of characters you typed since starting the Emacs session.
You should not even say "visit a file" instead of `C-x C-f' unless
you *know* that it makes no difference which visiting command is used.
Similarly, rather than saying "if I have three characters on the line,"
say "after I type `<RET> A B C <RET> C-p'," if that is the way you
entered the text.
So please don't guess any explanations when you report a bug. If you
want to actually *debug* the problem, and report explanations that are
more than guesses, that is useful--but please include the facts as well.
Checklist for Bug Reports
-------------------------
The best way to send a bug report is to mail it electronically to the
Emacs maintainers at `bug-gnu-emacs@gnu.org'. (If you want to suggest
a change as an improvement, use the same address.)
If you'd like to read the bug reports, you can find them on the
newsgroup `gnu.emacs.bug'; keep in mind, however, that as a spectator
you should not criticize anything about what you see there. The
purpose of bug reports is to give information to the Emacs maintainers.
Spectators are welcome only as long as they do not interfere with
this. In particular, some bug reports contain large amounts of data;
spectators should not complain about this.
Please do not post bug reports using netnews; mail is more reliable
than netnews about reporting your correct address, which we may need in
order to ask you for more information.
If you can't send electronic mail, then mail the bug report on paper
or machine-readable media to this address:
GNU Emacs Bugs
Free Software Foundation
59 Temple Place, Suite 330
Boston, MA 02111-1307 USA
We do not promise to fix the bug; but if the bug is serious, or
ugly, or easy to fix, chances are we will want to.
A convenient way to send a bug report for Emacs is to use the command
`M-x report-emacs-bug'. This sets up a mail buffer (*note Sending
Mail::.) and automatically inserts *some* of the essential information.
However, it cannot supply all the necessary information; you should
still read and follow the guidelines below, so you can enter the other
crucial information by hand before you send the message.
To enable maintainers to investigate a bug, your report should
include all these things:
* The version number of Emacs. Without this, we won't know whether
there is any point in looking for the bug in the current version
of GNU Emacs.
You can get the version number by typing `M-x emacs-version
<RET>'. If that command does not work, you probably have something
other than GNU Emacs, so you will have to report the bug somewhere
else.
* The type of machine you are using, and the operating system name
and version number. `M-x emacs-version <RET>' provides this
information too. Copy its output from the `*Messages*' buffer, so
that you get it all and get it accurately.
* The operands given to the `configure' command when Emacs was
installed.
* A complete list of any modifications you have made to the Emacs
source. (We may not have time to investigate the bug unless it
happens in an unmodified Emacs. But if you've made modifications
and you don't tell us, you are sending us on a wild goose chase.)
Be precise about these changes. A description in English is not
enough--send a context diff for them.
Adding files of your own, or porting to another machine, is a
modification of the source.
* Details of any other deviations from the standard procedure for
installing GNU Emacs.
* The complete text of any files needed to reproduce the bug.
If you can tell us a way to cause the problem without visiting any
files, please do so. This makes it much easier to debug. If you
do need files, make sure you arrange for us to see their exact
contents. For example, it can often matter whether there are
spaces at the ends of lines, or a newline after the last line in
the buffer (nothing ought to care whether the last line is
terminated, but try telling the bugs that).
* The precise commands we need to type to reproduce the bug.
The easy way to record the input to Emacs precisely is to write a
dribble file. To start the file, execute the Lisp expression
(open-dribble-file "~/dribble")
using `M-:' or from the `*scratch*' buffer just after starting
Emacs. From then on, Emacs copies all your input to the specified
dribble file until the Emacs process is killed.
* For possible display bugs, the terminal type (the value of
environment variable `TERM'), the complete termcap entry for the
terminal from `/etc/termcap' (since that file is not identical on
all machines), and the output that Emacs actually sent to the
terminal.
The way to collect the terminal output is to execute the Lisp
expression
(open-termscript "~/termscript")
using `M-:' or from the `*scratch*' buffer just after starting
Emacs. From then on, Emacs copies all terminal output to the
specified termscript file as well, until the Emacs process is
killed. If the problem happens when Emacs starts up, put this
expression into your `.emacs' file so that the termscript file
will be open when Emacs displays the screen for the first time.
Be warned: it is often difficult, and sometimes impossible, to fix
a terminal-dependent bug without access to a terminal of the type
that stimulates the bug.
* A description of what behavior you observe that you believe is
incorrect. For example, "The Emacs process gets a fatal signal,"
or, "The resulting text is as follows, which I think is wrong."
Of course, if the bug is that Emacs gets a fatal signal, then one
can't miss it. But if the bug is incorrect text, the maintainer
might fail to notice what is wrong. Why leave it to chance?
Even if the problem you experience is a fatal signal, you should
still say so explicitly. Suppose something strange is going on,
such as, your copy of the source is out of sync, or you have
encountered a bug in the C library on your system. (This has
happened!) Your copy might crash and the copy here might not. If
you *said* to expect a crash, then when Emacs here fails to crash,
we would know that the bug was not happening. If you don't say to
expect a crash, then we would not know whether the bug was
happening--we would not be able to draw any conclusion from our
observations.
* If the manifestation of the bug is an Emacs error message, it is
important to report the precise text of the error message, and a
backtrace showing how the Lisp program in Emacs arrived at the
error.
To get the error message text accurately, copy it from the
`*Messages*' buffer into the bug report. Copy all of it, not just
part.
To make a backtrace for the error, evaluate the Lisp expression
`(setq debug-on-error t)' before the error happens (that is to
say, you must execute that expression and then make the bug
happen). This causes the error to run the Lisp debugger, which
shows you a backtrace. Copy the text of the debugger's backtrace
into the bug report.
This use of the debugger is possible only if you know how to make
the bug happen again. If you can't make it happen again, at least
copy the whole error message.
* Check whether any programs you have loaded into the Lisp world,
including your `.emacs' file, set any variables that may affect the
functioning of Emacs. Also, see whether the problem happens in a
freshly started Emacs without loading your `.emacs' file (start
Emacs with the `-q' switch to prevent loading the init file). If
the problem does *not* occur then, you must report the precise
contents of any programs that you must load into the Lisp world in
order to cause the problem to occur.
* If the problem does depend on an init file or other Lisp programs
that are not part of the standard Emacs system, then you should
make sure it is not a bug in those programs by complaining to
their maintainers first. After they verify that they are using
Emacs in a way that is supposed to work, they should report the
bug.
* If you wish to mention something in the GNU Emacs source, show the
line of code with a few lines of context. Don't just give a line
number.
The line numbers in the development sources don't match those in
your sources. It would take extra work for the maintainers to
determine what code is in your version at a given line number, and
we could not be certain.
* Additional information from a C debugger such as GDB might enable
someone to find a problem on a machine which he does not have
available. If you don't know how to use GDB, please read the GDB
manual--it is not very long, and using GDB is easy. You can find
the GDB distribution, including the GDB manual in online form, in
most of the same places you can find the Emacs distribution. To
run Emacs under GDB, you should switch to the `src' subdirectory
in which Emacs was compiled, then do `gdb emacs'. It is important
for the directory `src' to be current so that GDB will read the
`.gdbinit' file in this directory.
However, you need to think when you collect the additional
information if you want it to show what causes the bug.
For example, many people send just a backtrace, but that is not
very useful by itself. A simple backtrace with arguments often
conveys little about what is happening inside GNU Emacs, because
most of the arguments listed in the backtrace are pointers to Lisp
objects. The numeric values of these pointers have no
significance whatever; all that matters is the contents of the
objects they point to (and most of the contents are themselves
pointers).
To provide useful information, you need to show the values of Lisp
objects in Lisp notation. Do this for each variable which is a
Lisp object, in several stack frames near the bottom of the stack.
Look at the source to see which variables are Lisp objects,
because the debugger thinks of them as integers.
To show a variable's value in Lisp syntax, first print its value,
then use the user-defined GDB command `pr' to print the Lisp
object in Lisp syntax. (If you must use another debugger, call
the function `debug_print' with the object as an argument.) The
`pr' command is defined by the file `.gdbinit', and it works only
if you are debugging a running process (not with a core dump).
To make Lisp errors stop Emacs and return to GDB, put a breakpoint
at `Fsignal'.
For a short listing of Lisp functions running, type the GDB
command `xbacktrace'.
If you want to examine Lisp function arguments, move up the stack,
and each time you get to a frame for the function `Ffuncall', type
these GDB commands:
p *args
pr
To print the first argument that the function received, use these
commands:
p args[1]
pr
You can print the other arguments likewise. The argument `nargs'
of `Ffuncall' says how many arguments `Ffuncall' received; these
include the Lisp function itself and the arguments for that
function.
The file `.gdbinit' defines several other commands that are useful
for examining the data types and contents of Lisp objects. Their
names begin with `x'. These commands work at a lower level than
`pr', and are less convenient, but they may work even when `pr'
does not, such as when debugging a core dump or when Emacs has had
a fatal signal.
* If the symptom of the bug is that Emacs fails to respond, don't
assume Emacs is "hung"--it may instead be in an infinite loop. To
find out which, make the problem happen under GDB and stop Emacs
once it is not responding. (If Emacs is using X Windows directly,
you can stop Emacs by typing `C-z' at the GDB job.) Then try
stepping with `step'. If Emacs is hung, the `step' command won't
return. If it is looping, `step' will return.
If this shows Emacs is hung in a system call, stop it again and
examine the arguments of the call. In your bug report, state
exactly where in the source the system call is, and what the
arguments are.
If Emacs is in an infinite loop, please determine where the loop
starts and ends. The easiest way to do this is to use the GDB
command `finish'. Each time you use it, Emacs resumes execution
until it exits one stack frame. Keep typing `finish' until it
doesn't return--that means the infinite loop is in the stack frame
which you just tried to finish.
Stop Emacs again, and use `finish' repeatedly again until you get
*back to* that frame. Then use `next' to step through that frame.
By stepping, you will see where the loop starts and ends. Also
please examine the data being used in the loop and try to
determine why the loop does not exit when it should. Include all
of this information in your bug report.
Here are some things that are not necessary in a bug report:
* A description of the envelope of the bug--this is not necessary
for a reproducible bug.
Often people who encounter a bug spend a lot of time investigating
which changes to the input file will make the bug go away and which
changes will not affect it.
This is often time-consuming and not very useful, because the way
we will find the bug is by running a single example under the
debugger with breakpoints, not by pure deduction from a series of
examples. You might as well save time by not searching for
additional examples.
Of course, if you can find a simpler example to report *instead* of
the original one, that is a convenience. Errors in the output
will be easier to spot, running under the debugger will take less
time, etc.
However, simplification is not vital; if you can't do this or
don't have time to try, please report the bug with your original
test case.
* A system-call trace of Emacs execution.
System-call traces are very useful for certain special kinds of
debugging, but in most cases they give little useful information.
It is therefore strange that many people seem to think that *the*
way to report information about a crash is to send a system-call
trace. Perhaps this is a habit formed from experience debugging
programs that don't have source code or debugging symbols.
In most programs, a backtrace is normally far, far more
informative than a system-call trace. Even in Emacs, a simple
backtrace is generally more informative, though to give full
information you should supplement the backtrace by displaying
variable values and printing them as Lisp objects with `pr' (see
above).
* A patch for the bug.
A patch for the bug is useful if it is a good one. But don't omit
the other information that a bug report needs, such as the test
case, on the assumption that a patch is sufficient. We might see
problems with your patch and decide to fix the problem another
way, or we might not understand it at all. And if we can't
understand what bug you are trying to fix, or why your patch
should be an improvement, we mustn't install it.
*Note Sending Patches::, for guidelines on how to make it easy for
us to understand and install your patches.
* A guess about what the bug is or what it depends on.
Such guesses are usually wrong. Even experts can't guess right
about such things without first using the debugger to find the
facts.
Sending Patches for GNU Emacs
-----------------------------
If you would like to write bug fixes or improvements for GNU Emacs,
that is very helpful. When you send your changes, please follow these
guidelines to make it easy for the maintainers to use them. If you
don't follow these guidelines, your information might still be useful,
but using it will take extra work. Maintaining GNU Emacs is a lot of
work in the best of circumstances, and we can't keep up unless you do
your best to help.
* Send an explanation with your changes of what problem they fix or
what improvement they bring about. For a bug fix, just include a
copy of the bug report, and explain why the change fixes the bug.
(Referring to a bug report is not as good as including it, because
then we will have to look it up, and we have probably already
deleted it if we've already fixed the bug.)
* Always include a proper bug report for the problem you think you
have fixed. We need to convince ourselves that the change is
right before installing it. Even if it is correct, we might have
trouble understanding it if we don't have a way to reproduce the
problem.
* Include all the comments that are appropriate to help people
reading the source in the future understand why this change was
needed.
* Don't mix together changes made for different reasons. Send them
*individually*.
If you make two changes for separate reasons, then we might not
want to install them both. We might want to install just one. If
you send them all jumbled together in a single set of diffs, we
have to do extra work to disentangle them--to figure out which
parts of the change serve which purpose. If we don't have time
for this, we might have to ignore your changes entirely.
If you send each change as soon as you have written it, with its
own explanation, then two changes never get tangled up, and we can
consider each one properly without any extra work to disentangle
them.
* Send each change as soon as that change is finished. Sometimes
people think they are helping us by accumulating many changes to
send them all together. As explained above, this is absolutely
the worst thing you could do.
Since you should send each change separately, you might as well
send it right away. That gives us the option of installing it
immediately if it is important.
* Use `diff -c' to make your diffs. Diffs without context are hard
to install reliably. More than that, they are hard to study; we
must always study a patch to decide whether we want to install it.
Unidiff format is better than contextless diffs, but not as easy
to read as `-c' format.
If you have GNU diff, use `diff -c -F'^[_a-zA-Z0-9$]+ *('' when
making diffs of C code. This shows the name of the function that
each change occurs in.
* Avoid any ambiguity as to which is the old version and which is
the new. Please make the old version the first argument to diff,
and the new version the second argument. And please give one
version or the other a name that indicates whether it is the old
version or your new changed one.
* Write the change log entries for your changes. This is both to
save us the extra work of writing them, and to help explain your
changes so we can understand them.
The purpose of the change log is to show people where to find what
was changed. So you need to be specific about what functions you
changed; in large functions, it's often helpful to indicate where
within the function the change was.
On the other hand, once you have shown people where to find the
change, you need not explain its purpose in the change log. Thus,
if you add a new function, all you need to say about it is that it
is new. If you feel that the purpose needs explaining, it
probably does--but put the explanation in comments in the code.
It will be more useful there.
Please read the `ChangeLog' files in the `src' and `lisp'
directories to see what sorts of information to put in, and to
learn the style that we use. If you would like your name to
appear in the header line, showing who made the change, send us
the header line. *Note Change Log::.
* When you write the fix, keep in mind that we can't install a
change that would break other systems. Please think about what
effect your change will have if compiled on another type of system.
Sometimes people send fixes that *might* be an improvement in
general--but it is hard to be sure of this. It's hard to install
such changes because we have to study them very carefully. Of
course, a good explanation of the reasoning by which you concluded
the change was correct can help convince us.
The safest changes are changes to the configuration files for a
particular machine. These are safe because they can't create new
bugs on other machines.
Please help us keep up with the workload by designing the patch in
a form that is clearly safe to install.
Contributing to Emacs Development
=================================
If you would like to help pretest Emacs releases to assure they work
well, or if you would like to work on improving Emacs, please contact
the maintainers at `bug-gnu-emacs@gnu.org'. A pretester should be
prepared to investigate bugs as well as report them. If you'd like to
work on improving Emacs, please ask for suggested projects or suggest
your own ideas.
If you have already written an improvement, please tell us about it.
If you have not yet started work, it is useful to contact
`bug-gnu-emacs@gnu.org' before you start; it might be possible to
suggest ways to make your extension fit in better with the rest of
Emacs.
How To Get Help with GNU Emacs
==============================
If you need help installing, using or changing GNU Emacs, there are
two ways to find it:
* Send a message to the mailing list `help-gnu-emacs@gnu.org', or
post your request on newsgroup `gnu.emacs.help'. (This mailing
list and newsgroup interconnect, so it does not matter which one
you use.)
* Look in the service directory for someone who might help you for a
fee. The service directory is found in the file named
`etc/SERVICE' in the Emacs distribution.
Command Line Arguments
**********************
GNU Emacs supports command line arguments to request various actions
when invoking Emacs. These are for compatibility with other editors and
for sophisticated activities. We don't recommend using them for
ordinary editing.
Arguments starting with `-' are "options". Other arguments specify
files to visit. Emacs visits the specified files while it starts up.
The last file name on your command line becomes the current buffer; the
other files are also present in other buffers. As usual, the special
argument `--' says that all subsequent arguments are file names, not
options, even if they start with `-'.
Emacs command options can specify many things, such as the size and
position of the X window Emacs uses, its colors, and so on. A few
options support advanced usage, such as running Lisp functions on files
in batch mode. The sections of this chapter describe the available
options, arranged according to their purpose.
There are two ways of writing options: the short forms that start
with a single `-', and the long forms that start with `--'. For
example, `-d' is a short form and `--display' is the corresponding long
form.
The long forms with `--' are easier to remember, but longer to type.
However, you don't have to spell out the whole option name; any
unambiguous abbreviation is enough. When a long option takes an
argument, you can use either a space or an equal sign to separate the
option name and the argument. Thus, you can write either `--display
sugar-bombs:0.0' or `--display=sugar-bombs:0.0'. We recommend an equal
sign because it makes the relationship clearer, and the tables below
always show an equal sign.
Most options specify how to initialize Emacs, or set parameters for
the Emacs session. We call them "initial options". A few options
specify things to do: for example, load libraries, call functions, or
exit Emacs. These are called "action options". These and file names
together are called "action arguments". Emacs processes all the action
arguments in the order they are written.
Action Arguments
================
Here is a table of the action arguments and options:
`FILE'
Visit FILE using `find-file'. *Note Visiting::.
`+LINENUM FILE'
Visit FILE using `find-file', then go to line number LINENUM in it.
`-l FILE'
`--load=FILE'
Load a Lisp library named FILE with the function `load'. *Note
Lisp Libraries::. The library can be found either in the current
directory, or in the Emacs library search path as specified with
`EMACSLOADPATH' (*note General Variables::.).
`-f FUNCTION'
`--funcall=FUNCTION'
Call Lisp function FUNCTION with no arguments.
`--eval EXPRESSION'
Evaluate Lisp expression EXPRESSION.
`--insert=FILE'
Insert the contents of FILE into the current buffer. This is like
what `M-x insert-file' does. *Note Misc File Ops::.
`--kill'
Exit from Emacs without asking for confirmation.
The init file can access the values of the action arguments as the
elements of a list in the variable `command-line-args'. The init file
can override the normal processing of the action arguments, or define
new ones, by reading and setting this variable.
Initial Options
===============
The initial options specify parameters for the Emacs session. This
section describes the more general initial options; some other options
specifically related to X Windows appear in the following sections.
Some initial options affect the loading of init files. The normal
actions of Emacs are to first load `site-start.el' if it exists, then
your own init file `~/.emacs' if it exists, and finally `default.el' if
it exists; certain options prevent loading of some of these files or
substitute other files for them.
`-t DEVICE'
`--terminal=DEVICE'
Use DEVICE as the device for terminal input and output.
`-d DISPLAY'
`--display=DISPLAY'
Use the X Window System and use the display named DISPLAY to open
the initial Emacs frame.
`-nw'
`--no-windows'
Don't communicate directly with X, disregarding the `DISPLAY'
environment variable even if it is set.
`-batch'
`--batch'
Run Emacs in "batch mode", which means that the text being edited
is not displayed and the standard terminal interrupt characters
such as `C-z' and `C-c' continue to have their normal effect.
Emacs in batch mode outputs to `stderr' only what would normally
be printed in the echo area under program control.
Batch mode is used for running programs written in Emacs Lisp from
shell scripts, makefiles, and so on. Normally the `-l' option or
`-f' option will be used as well, to invoke a Lisp program to do
the batch processing.
`-batch' implies `-q' (do not load an init file). It also causes
Emacs to kill itself after all command options have been
processed. In addition, auto-saving is not done except in buffers
for which it has been explicitly requested.
`-q'
`--no-init-file'
Do not load your Emacs init file `~/.emacs', or `default.el'
either.
`--no-site-file'
Do not load `site-start.el'. The options `-q', `-u' and `-batch'
have no effect on the loading of this file--this is the only
option that blocks it.
`-u USER'
`--user=USER'
Load USER's Emacs init file `~USER/.emacs' instead of your own.
`--debug-init'
Enable the Emacs Lisp debugger for errors in the init file.
`--unibyte'
Set up to do almost everything with single-byte buffers and
strings. All buffers and strings are unibyte unless you (or a
Lisp program) explicitly ask for a multibyte buffer or string.
Setting the environment variable `EMACS_UNIBYTE' has the same
effect.
`--multibyte'
Inhibit the effect of `EMACS_UNIBYTE', so that Emacs uses
multibyte characters by default, as usual.
Command Argument Example
========================
Here is an example of using Emacs with arguments and options. It
assumes you have a Lisp program file called `hack-c.el' which, when
loaded, performs some useful operation on the current buffer, expected
to be a C program.
emacs -batch foo.c -l hack-c -f save-buffer >& log
This says to visit `foo.c', load `hack-c.el' (which makes changes in
the visited file), save `foo.c' (note that `save-buffer' is the
function that `C-x C-s' is bound to), and then exit back to the shell
(because of `-batch'). `-batch' also guarantees there will be no
problem redirecting output to `log', because Emacs will not assume that
it has a display terminal to work with.
Resuming Emacs with Arguments
=============================
You can specify action arguments for Emacs when you resume it after
a suspension. To prepare for this, put the following code in your
`.emacs' file (*note Hooks::.):
(add-hook 'suspend-hook 'resume-suspend-hook)
(add-hook 'suspend-resume-hook 'resume-process-args)
As further preparation, you must execute the shell script
`emacs.csh' (if you use csh as your shell) or `emacs.bash' (if you use
bash as your shell). These scripts define an alias named `edit', which
will resume Emacs giving it new command line arguments such as files to
visit.
Only action arguments work properly when you resume Emacs. Initial
arguments are not recognized--it's too late to execute them anyway.
Note that resuming Emacs (with or without arguments) must be done
from within the shell that is the parent of the Emacs job. This is why
`edit' is an alias rather than a program or a shell script. It is not
possible to implement a resumption command that could be run from other
subjobs of the shell; no way to define a command that could be made the
value of `EDITOR', for example. Therefore, this feature does not take
the place of the Emacs Server feature (*note Emacs Server::.).
The aliases use the Emacs Server feature if you appear to have a
server Emacs running. However, they cannot determine this with complete
accuracy. They may think that a server is still running when in
actuality you have killed that Emacs, because the file `/tmp/.esrv...'
still exists. If this happens, find that file and delete it.
Environment Variables
=====================
This appendix describes how Emacs uses environment variables. An
environment variable is a string passed from the operating system to
Emacs, and the collection of environment variables is known as the
environment. Environment variable names are case sensitive and it is
conventional to use upper case letters only.
Because environment variables come from the operating system there
is no general way to set them; it depends on the operating system and
especially the shell that you are using. For example, here's how to set
the environment variable `ORGANIZATION' to `not very much' using bash:
export ORGANIZATION="not very much"
and here's how to do it in csh or tcsh:
setenv ORGANIZATION "not very much"
When Emacs is set-up to use the X windowing system, it inherits the
use of a large number of environment variables from the X library. See
the X documentation for more information.
General Variables
-----------------
`AUTHORCOPY'
The name of a file used to archive news articles posted with the
GNUS package.
`CDPATH'
Used by the `cd' command to search for the directory you specify,
when you specify a relative directory name.
`DOMAINNAME'
The name of the Internet domain that the machine running Emacs is
located in. Used by the GNUS package.
`EMACS_UNIBYTE'
Defining this environment variable directs Emacs to do almost
everything with single-byte buffers and strings. It is equivalent
to using the `--unibyte' command-line option on each invocation.
*Note Initial Options::.
`EMACSDATA'
Used to initialize the variable `data-directory' used to locate the
architecture-independent files that come with Emacs. Setting this
variable overrides the setting in `paths.h' when Emacs was built.
`EMACSLOADPATH'
A colon-separated list of directories from which to load Emacs Lisp
files. Setting this variable overrides the setting in `paths.h'
when Emacs was built.
`EMACSLOCKDIR'
The directory that Emacs places lock files--files used to protect
users from editing the same files simultaneously. Setting this
variable overrides the setting in `paths.h' when Emacs was built.
`EMACSPATH'
The location of Emacs-specific binaries. Setting this variable
overrides the setting in `paths.h' when Emacs was built.
`ESHELL'
Used for shell-mode to override the `SHELL' environment variable.
`HISTFILE'
The name of the file that shell commands are saved in between
logins. This variable defaults to `~/.history' if you use (t)csh
as shell, to `~/.bash_history' if you use bash, to `~/.sh_history'
if you use ksh, and to `~/.history' otherwise.
`HOME'
The location of the user's files in the directory tree; used for
expansion of file names starting with a tilde (`~'). On MS-DOS, it
defaults to the directory from which Emacs was started, with `/bin'
removed from the end if it was present.
`HOSTNAME'
The name of the machine that Emacs is running on.
`INCPATH'
A colon-separated list of directories. Used by the `complete'
package to search for files.
`INFOPATH'
A colon-separated list of directories holding info files. Setting
this variable overrides the setting in `paths.el' when Emacs was
built.
`LANG'
`LC_ALL'
`LC_CTYPE'
The user's preferred locale. A locale name which contains
`8859-N', `8859_N' or `8859N', where N is between 1 and 4,
automatically specifies the `Latin-N' language environment when
Emacs starts up. If N is 9, that specifies `Latin-5'.
`LOGNAME'
The user's login name. See also `USER'.
`MAIL'
The name of the user's system mail inbox.
`MAILRC'
Name of file containing mail aliases. This defaults to
`~/.mailrc'.
`MH'
Name of setup file for the mh system. This defaults to
`~/.mh_profile'.
`NAME'
The real-world name of the user.
`NNTPSERVER'
The name of the news server. Used by the mh and GNUS packages.
`ORGANIZATION'
The name of the organization to which you belong. Used for
setting the `Organization:' header in your posts from the GNUS
package.
`PATH'
A colon-separated list of directories in which executables reside.
(On MS-DOS, it is semicolon-separated instead.) This variable is
used to set the Emacs Lisp variable `exec-path' which you should
consider to use instead.
`PWD'
If set, this should be the default directory when Emacs was
started.
`REPLYTO'
If set, this specifies an initial value for the variable
`mail-default-reply-to'. *Note Mail Headers::.
`SAVEDIR'
The name of a directory in which news articles are saved by
default. Used by the GNUS package.
`SHELL'
The name of an interpreter used to parse and execute programs run
from inside Emacs.
`TERM'
The name of the terminal that Emacs is running on. The variable
must be set unless Emacs is run in batch mode. On MS-DOS, it
defaults to `internal', which specifies a built-in terminal
emulation that handles the machine's own display.
`TERMCAP'
The name of the termcap library file describing how to program the
terminal specified by the `TERM' variable. This defaults to
`/etc/termcap'.
`TMPDIR'
Used by the Emerge package as a prefix for temporary files.
`TZ'
This specifies the current time zone and possibly also daylight
savings information. On MS-DOS, the default is based on country
code; see the file `msdos.c' for details.
`USER'
The user's login name. See also `LOGNAME'. On MS-DOS, this
defaults to `root'.
`VERSION_CONTROL'
Used to initialize the `version-control' variable (*note Backup
Names::.).
Miscellaneous Variables
-----------------------
These variables are used only on particular configurations:
`COMSPEC'
On MS-DOS, the name of the command interpreter to use. This is
used to make a default value for the `SHELL' environment variable.
`NAME'
On MS-DOS, this variable defaults to the value of the `USER'
variable.
`TEMP'
`TMP'
On MS-DOS, these specify the name of the directory for storing
temporary files in.
`EMACSTEST'
On MS-DOS, this specifies a file to use to log the operation of the
internal terminal emulator. This feature is useful for submitting
bug reports.
`EMACSCOLORS'
Used on MS-DOS systems to set screen colors early, so that the
screen won't momentarily flash the default colors when Emacs
starts up. The value of this variable should be two-character
encoding of the foreground (the first character) and the
background (the second character) colors of the default face.
Each character should be the hexadecimal code for the desired
color on a standard PC text-mode display.
The PC display usually supports only eight background colors.
However, Emacs switches the DOS display to a mode where all 16
colors can be used for the background, so all four bits of the
background color are actually used.
`WINDOW_GFX'
Used when initializing the Sun windows system.
Specifying the Display Name
===========================
The environment variable `DISPLAY' tells all X clients, including
Emacs, where to display their windows. Its value is set up by default
in ordinary circumstances, when you start an X server and run jobs
locally. Occasionally you may need to specify the display yourself; for
example, if you do a remote login and want to run a client program
remotely, displaying on your local screen.
With Emacs, the main reason people change the default display is to
let them log into another system, run Emacs on that system, but have the
window displayed at their local terminal. You might need to use login
to another system because the files you want to edit are there, or
because the Emacs executable file you want to run is there.
The syntax of the `DISPLAY' environment variable is
`HOST:DISPLAY.SCREEN', where HOST is the host name of the X Window
System server machine, DISPLAY is an arbitrarily-assigned number that
distinguishes your server (X terminal) from other servers on the same
machine, and SCREEN is a rarely-used field that allows an X server to
control multiple terminal screens. The period and the SCREEN field are
optional. If included, SCREEN is usually zero.
For example, if your host is named `glasperle' and your server is
the first (or perhaps the only) server listed in the configuration, your
`DISPLAY' is `glasperle:0.0'.
You can specify the display name explicitly when you run Emacs,
either by changing the `DISPLAY' variable, or with the option `-d
DISPLAY' or `--display=DISPLAY'. Here is an example:
emacs --display=glasperle:0 &
You can inhibit the direct use of X with the `-nw' option. This is
also an initial option. It tells Emacs to display using ordinary ASCII
on its controlling terminal.
Sometimes, security arrangements prevent a program on a remote system
from displaying on your local system. In this case, trying to run Emacs
produces messages like this:
Xlib: connection to "glasperle:0.0" refused by server
You might be able to overcome this problem by using the `xhost' command
on the local system to give permission for access from your remote
machine.
Font Specification Options
==========================
By default, Emacs displays text in the font named `9x15', which
makes each character nine pixels wide and fifteen pixels high. You can
specify a different font on your command line through the option `-fn
NAME'.
`-fn NAME'
Use font NAME as the default font.
`--font=NAME'
`--font' is an alias for `-fn'.
Under X, each font has a long name which consists of eleven words or
numbers, separated by dashes. Some fonts also have shorter
nicknames--`9x15' is such a nickname. You can use either kind of name.
You can use wildcard patterns for the font name; then Emacs lets X
choose one of the fonts that match the pattern. Here is an example,
which happens to specify the font whose nickname is `6x13':
emacs -fn "-misc-fixed-medium-r-semicondensed--13-*-*-*-c-60-iso8859-1" &
You can also specify the font in your `.Xdefaults' file:
emacs.font: -misc-fixed-medium-r-semicondensed--13-*-*-*-c-60-iso8859-1
A long font name has the following form:
-MAKER-FAMILY-WEIGHT-SLANT-WIDTHTYPE-STYLE...
...-PIXELS-HEIGHT-HORIZ-VERT-SPACING-WIDTH-CHARSET
FAMILY
This is the name of the font family--for example, `courier'.
WEIGHT
This is normally `bold', `medium' or `light'. Other words may
appear here in some font names.
SLANT
This is `r' (roman), `i' (italic), `o' (oblique), `ri' (reverse
italic), or `ot' (other).
WIDTHTYPE
This is normally `condensed', `extended', `semicondensed' or
`normal'. Other words may appear here in some font names.
STYLE
This is an optional additional style name. Usually it is
empty--most long font names have two hyphens in a row at this
point.
PIXELS
This is the font height, in pixels.
HEIGHT
This is the font height on the screen, measured in tenths of a
printer's point--approximately 1/720 of an inch. In other words,
it is the point size of the font, times ten. For a given vertical
resolution, HEIGHT and PIXELS are proportional; therefore, it is
common to specify just one of them and use `*' for the other.
HORIZ
This is the horizontal resolution, in pixels per inch, of the
screen for which the font is intended.
VERT
This is the vertical resolution, in dots per inch, of the screen
for which the font is intended. Normally the resolution of the
fonts on your system is the right value for your screen;
therefore, you normally specify `*' for this and HORIZ.
SPACING
This is `m' (monospace), `p' (proportional) or `c' (character
cell). Emacs can use `m' and `c' fonts.
WIDTH
This is the average character width, in pixels, multiplied by ten.
CHARSET
This is the character set that the font depicts. Normally you
should use `iso8859-1'.
Use only fixed-width fonts--that is, fonts in which all characters
have the same width; Emacs cannot yet handle display properly for
variable-width fonts. Any font with `m' or `c' in the SPACING field of
the long name is a fixed-width font. Here's how to use the `xlsfonts'
program to list all the fixed-width fonts available on your system:
xlsfonts -fn '*x*' | egrep "^[0-9]+x[0-9]+"
xlsfonts -fn '*-*-*-*-*-*-*-*-*-*-*-m*'
xlsfonts -fn '*-*-*-*-*-*-*-*-*-*-*-c*'
To see what a particular font looks like, use the `xfd' command. For
example:
xfd -fn 6x13
displays the entire font `6x13'.
While running Emacs, you can set the font of the current frame
(*note Frame Parameters::.) or for a specific kind of text (*note
Faces::.).
Window Color Options
====================
On a color display, you can specify which color to use for various
parts of the Emacs display. To find out what colors are available on
your system, look at the `/usr/lib/X11/rgb.txt' file. If you do not
specify colors, the default for the background is white and the default
for all other colors is black. On a monochrome display, the foreground
is black, the background is white, and the border is gray if the
display supports that.
Here is a list of the options for specifying colors:
`-fg COLOR'
`--foreground-color=COLOR'
Specify the foreground color.
`-bg COLOR'
`--background-color=COLOR'
Specify the background color.
`-bd COLOR'
`--border-color=COLOR'
Specify the color of the border of the X window.
`-cr COLOR'
`--cursor-color=COLOR'
Specify the color of the Emacs cursor which indicates where point
is.
`-ms COLOR'
`--mouse-color=COLOR'
Specify the color for the mouse cursor when the mouse is in the
Emacs window.
`-r'
`--reverse-video'
Reverse video--swap the foreground and background colors.
For example, to use a coral mouse cursor and a slate blue text
cursor, enter:
emacs -ms coral -cr 'slate blue' &
You can reverse the foreground and background colors through the
`-r' option or with the X resource `reverseVideo'.
Options for Window Geometry
===========================
The `-geometry' option controls the size and position of the initial
Emacs frame. Here is the format for specifying the window geometry:
`-g WIDTHxHEIGHT{+-}XOFFSET{+-}YOFFSET'
Specify window size WIDTH and HEIGHT (measured in character
columns and lines), and positions XOFFSET and YOFFSET (measured in
pixels).
`--geometry=WIDTHxHEIGHT{+-}XOFFSET{+-}YOFFSET'
This is another way of writing the same thing.
`{+-}' means either a plus sign or a minus sign. A plus sign before
XOFFSET means it is the distance from the left side of the screen; a
minus sign means it counts from the right side. A plus sign before
YOFFSET means it is the distance from the top of the screen, and a
minus sign there indicates the distance from the bottom. The values
XOFFSET and YOFFSET may themselves be positive or negative, but that
doesn't change their meaning, only their direction.
Emacs uses the same units as `xterm' does to interpret the geometry.
The WIDTH and HEIGHT are measured in characters, so a large font
creates a larger frame than a small font. The XOFFSET and YOFFSET are
measured in pixels.
Since the mode line and the echo area occupy the last 2 lines of the
frame, the height of the initial text window is 2 less than the height
specified in your geometry. In non-X-toolkit versions of Emacs, the
menu bar also takes one line of the specified number.
You do not have to specify all of the fields in the geometry
specification.
If you omit both XOFFSET and YOFFSET, the window manager decides
where to put the Emacs frame, possibly by letting you place it with the
mouse. For example, `164x55' specifies a window 164 columns wide,
enough for two ordinary width windows side by side, and 55 lines tall.
The default width for Emacs is 80 characters and the default height
is 40 lines. You can omit either the width or the height or both. If
you start the geometry with an integer, Emacs interprets it as the
width. If you start with an `x' followed by an integer, Emacs
interprets it as the height. Thus, `81' specifies just the width;
`x45' specifies just the height.
If you start with `+' or `-', that introduces an offset, which means
both sizes are omitted. Thus, `-3' specifies the XOFFSET only. (If
you give just one offset, it is always XOFFSET.) `+3-3' specifies both
the XOFFSET and the YOFFSET, placing the frame near the bottom left of
the screen.
You can specify a default for any or all of the fields in
`.Xdefaults' file, and then override selected fields with a
`--geometry' option.
Internal and External Borders
=============================
An Emacs frame has an internal border and an external border. The
internal border is an extra strip of the background color around all
four edges of the frame. Emacs itself adds the internal border. The
external border is added by the window manager outside the internal
border; it may contain various boxes you can click on to move or iconify
the window.
`-ib WIDTH'
`--internal-border=WIDTH'
Specify WIDTH as the width of the internal border.
`-bw WIDTH'
`--border-width=WIDTH'
Specify WIDTH as the width of the main border.
When you specify the size of the frame, that does not count the
borders. The frame's position is measured from the outside edge of the
external border.
Use the `-ib N' option to specify an internal border N pixels wide.
The default is 1. Use `-bw N' to specify the width of the external
border (though the window manager may not pay attention to what you
specify). The default width of the external border is 2.
Frame Titles
============
An Emacs frame may or may not have a specified title. The frame
title, if specified, appears in window decorations and icons as the name
of the frame. If an Emacs frame has no specified title, the default
title is the name of the executable program (if there is only one frame)
or the selected window's buffer name (if there is more than one frame).
You can specify a title for the initial Emacs frame with a command
line option:
`-title TITLE'
`--title=TITLE'
`-T TITLE'
Specify TITLE as the title for the initial Emacs frame.
The `--name' option (*note Resources X::.) also specifies the title
for the initial Emacs frame.
Icons
=====
Most window managers allow the user to "iconify" a frame, removing
it from sight, and leaving a small, distinctive "icon" window in its
place. Clicking on the icon window makes the frame itself appear again.
If you have many clients running at once, you can avoid cluttering up
the screen by iconifying most of the clients.
`-i'
`--icon-type'
Use a picture of a gnu as the Emacs icon.
`-iconic'
`--iconic'
Start Emacs in iconified state.
The `-i' or `--icon-type' option tells Emacs to use an icon window
containing a picture of the GNU gnu. If omitted, Emacs lets the window
manager choose what sort of icon to use--usually just a small rectangle
containing the frame's title.
The `-iconic' option tells Emacs to begin running as an icon, rather
than opening a frame right away. In this situation, the icon window
provides only indication that Emacs has started; the usual text frame
doesn't appear until you deiconify it.
X Resources
===========
Programs running under the X Window System organize their user
options under a hierarchy of classes and resources. You can specify
default values for these options in your X resources file, usually named
`~/.Xdefaults'.
Each line in the file specifies a value for one option or for a
collection of related options, for one program or for several programs
(optionally even for all programs).
Programs define named resources with particular meanings. They also
define how to group resources into named classes. For instance, in
Emacs, the `internalBorder' resource controls the width of the internal
border, and the `borderWidth' resource controls the width of the
external border. Both of these resources are part of the `BorderWidth'
class. Case distinctions are significant in these names.
In `~/.Xdefaults', you can specify a value for a single resource on
one line, like this:
emacs.borderWidth: 2
Or you can use a class name to specify the same value for all resources
in that class. Here's an example:
emacs.BorderWidth: 2
If you specify a value for a class, it becomes the default for all
resources in that class. You can specify values for individual
resources as well; these override the class value, for those particular
resources. Thus, this example specifies 2 as the default width for all
borders, but overrides this value with 4 for the external border:
emacs.Borderwidth: 2
emacs.borderwidth: 4
The order in which the lines appear in the file does not matter.
Also, command-line options always override the X resources file.
The string `emacs' in the examples above is also a resource name.
It actually represents the name of the executable file that you invoke
to run Emacs. If Emacs is installed under a different name, it looks
for resources under that name instead of `emacs'.
`-name NAME'
`--name=NAME'
Use NAME as the resource name (and the title) for the initial
Emacs frame. This option does not affect subsequent frames, but
Lisp programs can specify frame names when they create frames.
If you don't specify this option, the default is to use the Emacs
executable's name as the resource name.
`-xrm RESOURCE-VALUES'
`--xrm=RESOURCE-VALUES'
Specify X resource values for this Emacs job (see below).
For consistency, `-name' also specifies the name to use for other
resource values that do not belong to any particular frame.
The resources that name Emacs invocations also belong to a class; its
name is `Emacs'. If you write `Emacs' instead of `emacs', the resource
applies to all frames in all Emacs jobs, regardless of frame titles and
regardless of the name of the executable file. Here is an example:
Emacs.BorderWidth: 2
Emacs.borderWidth: 4
You can specify a string of additional resource values for Emacs to
use with the command line option `-xrm RESOURCES'. The text RESOURCES
should have the same format that you would use inside a file of X
resources. To include multiple resource specifications in DATA, put a
newline between them, just as you would in a file. You can also use
`#include "FILENAME"' to include a file full of resource
specifications. Resource values specified with `-xrm' take precedence
over all other resource specifications.
The following table lists the resource names that designate options
for Emacs, each with the class that it belongs to:
`background' (class `Background')
Background color name.
`bitmapIcon' (class `BitmapIcon')
Use a bitmap icon (a picture of a gnu) if `on', let the window
manager choose an icon if `off'.
`borderColor' (class `BorderColor')
Color name for the external border.
`borderWidth' (class `BorderWidth')
Width in pixels of the external border.
`cursorColor' (class `Foreground')
Color name for text cursor (point).
`font' (class `Font')
Font name for text (or fontset name, *note Fontsets::.).
`foreground' (class `Foreground')
Color name for text.
`geometry' (class `Geometry')
Window size and position. Be careful not to specify this resource
as `emacs*geometry', because that may affect individual menus as
well as the Emacs frame itself.
If this resource specifies a position, that position applies only
to the initial Emacs frame (or, in the case of a resource for a
specific frame name, only that frame). However, the size if
specified here applies to all frames.
`iconName' (class `Title')
Name to display in the icon.
`internalBorder' (class `BorderWidth')
Width in pixels of the internal border.
`menuBar' (class `MenuBar')
Give frames menu bars if `on'; don't have menu bars if `off'.
`minibuffer' (class `Minibuffer')
If `none', don't make a minibuffer in this frame. It will use a
separate minibuffer frame instead.
`paneFont' (class `Font')
Font name for menu pane titles, in non-toolkit versions of Emacs.
`pointerColor' (class `Foreground')
Color of the mouse cursor.
`reverseVideo' (class `ReverseVideo')
Switch foreground and background default colors if `on', use
colors as specified if `off'.
`verticalScrollBars' (class `ScrollBars')
Give frames scroll bars if `on'; don't have scroll bars if `off'.
`selectionFont' (class `Font')
Font name for pop-up menu items, in non-toolkit versions of Emacs.
(For toolkit versions, see *Note Lucid Resources::, also see
*Note Motif Resources::.)
`title' (class `Title')
Name to display in the title bar of the initial Emacs frame.
Here are resources for controlling the appearance of particular faces
(*note Faces::.):
`FACE.attributeFont'
Font for face FACE.
`FACE.attributeForeground'
Foreground color for face FACE.
`FACE.attributeBackground'
Background color for face FACE.
`FACE.attributeUnderline'
Underline flag for face FACE. Use `on' or `true' for yes.
Lucid Menu X Resources
======================
If the Emacs installed at your site was built to use the X toolkit
with the Lucid menu widgets, then the menu bar is a separate widget and
has its own resources. The resource names contain `pane.menubar'
(following, as always, the name of the Emacs invocation or `Emacs'
which stands for all Emacs invocations). Specify them like this:
Emacs.pane.menubar.RESOURCE: VALUE
For example, to specify the font `8x16' for the menu-bar items, write
this:
Emacs.pane.menubar.font: 8x16
Resources for *non-menubar* toolkit pop-up menus have `menu*', in like
fashion. For example, to specify the font `8x16' for the pop-up menu
items, write this:
Emacs.menu*.font: 8x16
For dialog boxes, use `dialog' instead of `menu':
Emacs.dialog*.font: 8x16
Experience shows that on some systems you may need to add `shell.'
before the `pane.menubar' or `menu*'. On some other systems, you must
not add `shell.'.
Here is a list of the specific resources for menu bars and pop-up
menus:
`font'
Font for menu item text.
`foreground'
Color of the foreground.
`background'
Color of the background.
`buttonForeground'
In the menu bar, the color of the foreground for a selected item.
`horizontalSpacing'
Horizontal spacing in pixels between items. Default is 3.
`verticalSpacing'
Vertical spacing in pixels between items. Default is 1.
`arrowSpacing'
Horizontal spacing between the arrow (which indicates a submenu)
and the associated text. Default is 10.
`shadowThickness'
Thickness of shadow line around the widget.
Motif Menu X Resources
======================
If the Emacs installed at your site was built to use the X toolkit
with the Motif widgets, then the menu bar is a separate widget and has
its own resources. The resource names contain `pane.menubar'
(following, as always, the name of the Emacs invocation or `Emacs'
which stands for all Emacs invocations). Specify them like this:
Emacs.pane.menubar.SUBWIDGET.RESOURCE: VALUE
Each individual string in the menu bar is a subwidget; the
subwidget's name is the same as the menu item string. For example, the
word `Files' in the menu bar is part of a subwidget named
`emacs.pane.menubar.Files'. Most likely, you want to specify the same
resources for the whole menu bar. To do this, use `*' instead of a
specific subwidget name. For example, to specify the font `8x16' for
the menu-bar items, write this:
Emacs.pane.menubar.*.fontList: 8x16
This also specifies the resource value for submenus.
Each item in a submenu in the menu bar also has its own name for X
resources; for example, the `Files' submenu has an item named `Save
Buffer'. A resource specification for a submenu item looks like this:
Emacs.pane.menubar.popup_*.MENU.ITEM.RESOURCE: VALUE
For example, here's how to specify the font for the `Save Buffer' item:
Emacs.pane.menubar.popup_*.Files.Save Buffer.fontList: 8x16
For an item in a second-level submenu, such as `Check Message' under
`Spell' under `Edit', the resource fits this template:
Emacs.pane.menubar.popup_*.popup_*.MENU.RESOURCE: VALUE
For example,
Emacs.pane.menubar.popup_*.popup_*.Spell.Check Message: VALUE
It's impossible to specify a resource for all the menu-bar items
without also specifying it for the submenus as well. So if you want the
submenu items to look different from the menu bar itself, you must ask
for that in two steps. First, specify the resource for all of them;
then, override the value for submenus alone. Here is an example:
Emacs.pane.menubar.*.fontList: 8x16
Emacs.pane.menubar.popup_*.fontList: 8x16
For toolkit pop-up menus, use `menu*' instead of `pane.menubar'. For
example, to specify the font `8x16' for the pop-up menu items, write
this:
Emacs.menu*.fontList: 8x16
Here is a list of the specific resources for menu bars and pop-up
menus:
`armColor'
The color to show in an armed button.
`fontList'
The font to use.
`marginBottom'
`marginHeight'
`marginLeft'
`marginRight'
`marginTop'
`marginWidth'
Amount of space to leave around the item, within the border.
`borderWidth'
The width of border around the menu item, on all sides.
`shadowThickness'
The width of the border shadow.
`bottomShadowColor'
The color for the border shadow, on the bottom and the right.
`topShadowColor'
The color for the border shadow, on the top and the left.
Emacs 19 Antinews
*****************
For those users who live backwards in time, here is information about
downgrading to Emacs version 19. We hope you will enjoy the greater
simplicity that results from the absence of certain Emacs 20 features.
* The multibyte character and end-of-line conversion support have
been eliminated entirely. (Some users consider this a tremendous
improvement.) Character codes are limited to the range 0 through
255 and files imported onto Unix-like systems may have a ^M at the
end of each line to remind you to control MS-DOG type files.
* Fontsets, coding systems and input methods have been eliminated as
well.
* The mode line normally displays the string `Emacs', in case you
forget what editor you are using.
* Scroll bars always appear on the right-hand side of the window.
This clearly separates them from the text in the window.
* The `M-x customize' feature has been replaced with a very simple
feature, `M-x edit-options'. This shows you *all* the user
options right from the start, so you don't have to hunt for the
ones you want. It also provides a few commands, such as `s' and
`x', to set a user option.
* The <DELETE> key does nothing special in Emacs 19 when you use it
after selecting a region with the mouse. It does exactly the same
thing in that situation as it does at all other times: delete one
character backwards.
* `C-x C-w' no longer changes the major mode according to the new
file name. If you want to change the mode, use `M-x normal-mode'.
* In Transient Mark mode, each window displays highlighting for the
region as it exists in that window.
* Outline mode doesn't use overlay properties; instead, it hides a
line by converting the preceding newline into code 015.
Magically, however, if you save the file, the 015 character
appears in the file as a newline.
* There is now a clever way you can activate the minibuffer
recursively even if `enable-recursive-minibuffers' is `nil'. All
you have to do is *switch windows* to a non-minibuffer window, and
then use a minibuffer command. You can pile up any number of
minibuffer levels this way, but `M-x top-level' will get you out
of all of them.
* We have removed the limit on the length of minibuffer history
lists; they now contain all the minibuffer arguments you have used
since the beginning of the session.
* Dynamic abbrev expansion now handles case conversion in a very
simple and straightforward way. If you have requested preserving
case, it always converts the entire expansion to the case pattern
of the abbrev that you have typed in.
* The `compose-mail' command does not exist; `C-x m' now runs `mail'
directly.
* There is no way to quote a file name with special characters in it.
What you see is what you get: if the name looks remote, it is
remote.
* `M-x grep-find' has been eliminated, because `grep' has never been
lost.
* Some Dired commands have been rearranged: two-character sequences
have been replaced with quick single-character commands:
* For `dired-mark-executables', type `*'.
* For `dired-mark-directories', type `/'.
* For `dired-mark-symlinks', type `@'.
* For `dired-change-marks', type `c'.
* For `dired-unmark-all-files', type `C-M-?'.
* For `dired-unmark-all-marks', type `C-M-? <RET>'.
But if you want to use `dired-flag-garbage-files', `&', you'll
just have to stop living in the past.
* In C mode, you can now specify your preferred style for block
comments. If you want to use the style
/*
blah
blah
*/
then you should set the variable `c-block-comments-indent-p' to
`t'.
* To customize faces used by Font Lock mode, use the variable
`font-lock-face-attributes'. See its documentation string for
details.
* For efficiency, Font Lock mode now uses by default the minimum
supported level of decoration for the selected major mode.
* If you kill a buffer, any registers holding saved positions in that
buffer are changed to point into limbo.
* The function `set-frame-font' has been renamed to
`set-default-font'.
* The variable `tex-main-file' doesn't exist. Of course, you can
create the variable by setting it, but that won't do anything
special.
* The `scroll-preserve-screen-position' variable has been eliminated;
and so has the feature that it controls.
* We have eliminated the functions `add-untranslated-filesystem' and
`remove-untranslated-filesystem', and replaced them with a simpler
function, `using-unix-filesystems'.
* To keep up with decreasing computer memory capacity, many other
functions and files have been eliminated in Emacs 19. There's no
need to mention them all here. If you try to use one of them,
you'll get an error message to tell you that it is undefined or
unbound.
Emacs and MS-DOS
****************
This section briefly describes the peculiarities of using Emacs under
the MS-DOS "operating system" (also known as "MS-DOG"). If you build
Emacs for MS-DOS, the binary will also run on Windows 3.X, Windows NT,
Windows 9X, or OS/2 as a DOS application; the information in this
chapter applies for all of those systems, if you use an Emacs that was
built for MS-DOS.
Note that it is possible to build Emacs specifically for Windows NT
or Windows 9X. If you do that, most of this chapter does not apply;
instead, you get behavior much closer to what is documented in the rest
of the manual, including support for long file names, multiple frames,
scroll bars, mouse menus, and subprocesses. However, the section on
text files and binary files does still apply. There are also two
sections at the end of this chapter which apply specifically for Windows
NT and 9X.
Keyboard and Mouse on MS-DOS
============================
The PC keyboard maps use the left <ALT> key as the <META> key. You
have two choices for emulating the <SUPER> and <HYPER> keys: choose
either the right <CTRL> key or the right <ALT> key by setting the
variables `dos-hyper-key' and `dos-super-key' to 1 or 2 respectively.
If neither `dos-super-key' nor `dos-hyper-key' is 1, then by default
the right <ALT> key is also mapped to the <META> key. However, if the
MS-DOS international keyboard support program `KEYB.COM' is installed,
Emacs will *not* map the right <ALT> to <META>, since it is used for
accessing characters like `~' and `@' on non-US keyboard layouts; in
this case, you may only use the left <ALT> as <META> key.
The variable `dos-keypad-mode' is a flag variable that controls what
key codes are returned by keys in the numeric keypad. You can also
define the keypad <ENTER> key to act like `C-j', by putting the
following line into your `_emacs' file:
;; Make the Enter key from the Numeric keypad act as C-j.
(define-key function-key-map [kp-enter] [?\C-j])
The key that is called <DEL> in Emacs (because that's how it is
designated on most workstations) is known as <BS> (backspace) on a PC.
That is why the PC-specific terminal initialization remaps the <BS> key
to act as <DEL>; the <DEL> key is remapped to act as `C-d' for the same
reasons.
Emacs built for MS-DOS recognizes `C-<BREAK>' as a quit character,
just like `C-g'. This is because Emacs cannot detect that you have
typed `C-g' until it is ready for more input. As a consequence, you
cannot use `C-g' to stop a running command (*note Quitting::.). By
contrast, `C-<BREAK>' *is* detected as soon as you type it (as `C-g' is
on other systems), so it can be used to stop a running command and for
emergency escape (*note Emergency Escape::.).
Emacs on MS-DOS supports a mouse (on the default terminal only).
The mouse commands work as documented, including those that use menus
and the menu bar (*note Menu Bar::.). Scroll bars don't work in MS-DOS
Emacs. PC mice usually have only two buttons; these act as `Mouse-1'
and `Mouse-2', but if you press both of them together, that has the
effect of `Mouse-3'.
Emacs built for MS-DOS supports clipboard operations when it runs on
Windows. Commands that put text on the kill ring, or yank text from the
ring, check the Windows clipboard first, just as Emacs does on X Windows
(*note Mouse Commands::.). Only the primary selection and the cut
buffer are supported by MS-DOS Emacs on Windows; the secondary
selection always appears as empty.
Due to the way clipboard access is implemented by Windows, the
length of text you can put into the clipboard is limited by the amount
of free DOS memory that is available to Emacs. Usually, up to 620KB of
text can be put into the clipboard, but this limit depends on the system
configuration and is lower if you run Emacs as a subprocess of another
program. If the killed text does not fit, Emacs prints a message
saying so, and does not put the text into the clipboard.
Null characters also cannot be put into the Windows clipboard. If
the killed text includes null characters, Emacs does not put such text
into the clipboard, and prints in the echo area a message to that
effect.
The variable `dos-display-scancodes', when non-`nil', directs Emacs
to display the ASCII value and the keyboard scan code of each
keystroke; this feature serves as a complement to the `view-lossage'
command, for debugging.
Display on MS-DOS
=================
Display on MS-DOS cannot use font variants, like bold or italic, but
it does support multiple faces, each of which can specify a foreground
and a background color. Therefore, you can get the full functionality
of Emacs packages that use fonts (such as `font-lock', Enriched Text
mode, and others) by defining the relevant faces to use different
colors. Use the `list-colors-display' command (*note Frame
Parameters::.) and the `list-faces-display' command (*note Faces::.) to
see what colors and faces are available and what they look like.
The section *Note MS-DOS and MULE::, later in this chapter, describes
how Emacs displays glyphs and characters which aren't supported by the
native font built into the DOS display.
Multiple frames (*note Frames::.) are supported on MS-DOS, but they
all overlap, so you only see a single frame at any given moment. That
single visible frame occupies the entire screen. When you run Emacs
from MS-Windows DOS box, you can make the visible frame smaller than
the full screen, but Emacs still cannot display more than a single
frame at a time.
The `mode4350' command switches the display to 43 or 50 lines,
depending on your hardware; the `mode25' command switches to the
default 80x25 screen size.
By default, Emacs only knows how to set screen sizes of 80 columns by
25, 28, 35, 40, 43 or 50 rows. However, if your video adapter has
special video modes that will switch the display to other sizes, you can
have Emacs support those too. When you ask Emacs to switch the frame to
N rows by M columns dimensions, it checks if there is a variable called
`screen-dimensions-NxM', and if so, uses its value (which must be an
integer) as the video mode to switch to. (Emacs switches to that video
mode by calling the BIOS `Set Video Mode' function with the value of
`screen-dimensions-NxM' in the `AL' register.) For example, suppose
your adapter will switch to 66x80 dimensions when put into video mode
85. Then you can make Emacs support this screen size by putting the
following into your `_emacs' file:
(setq screen-dimensions-66x80 85)
Since Emacs on MS-DOS can only set the frame size to specific
supported dimensions, it cannot honor every possible frame resizing
request. When an unsupported size is requested, Emacs chooses the next
larger supported size beyond the specified size. For example, if you
ask for 36x80 frame, you will get 40x80 instead.
The variables `screen-dimensions-NxM' are used only when they
exactly match the specified size; the search for the next larger
supported size ignores them. In the above example, even if your VGA
supports 38x80 dimensions and you define a variable
`screen-dimensions-38x80' with a suitable value, you will still get
40x80 screen when you ask for a 36x80 frame. If you want to get the
38x80 size in this case, you can do it by setting the variable named
`screen-dimensions-36x80' with the same video mode value as
`screen-dimensions-38x80'.
Changing frame dimensions on MS-DOS has the effect of changing all
the other frames to the new dimensions.
File Names on MS-DOS
====================
MS-DOS normally uses a backslash, `\', to separate name units within
a file name, instead of the slash used on other systems. Emacs on
MS-DOS permits use of either slash or backslash, and also knows about
drive letters in file names.
On MS-DOS, file names are case-insensitive and limited to eight
characters, plus optionally a period and three more characters. Emacs
knows enough about these limitations to handle file names that were
meant for other operating systems. For instance, leading dots `.' in
file names are invalid in MS-DOS, so Emacs transparently converts them
to underscores `_'; thus your default init file (*note Init File::.) is
called `_emacs' on MS-DOS. Excess characters before or after the
period are generally ignored by MS-DOS itself; thus, if you visit the
file `LongFileName.EvenLongerExtension', you will silently get
`longfile.eve', but Emacs will still display the long file name on the
mode line. Other than that, it's up to you to specify file names which
are valid under MS-DOS; the transparent conversion as described above
only works on file names built into Emacs.
The above restrictions on the file names on MS-DOS make it almost
impossible to construct the name of a backup file (*note Backup
Names::.) without losing some of the original file name characters. For
example, the name of a backup file for `docs.txt' is `docs.tx~' even if
single backup is used.
If you run Emacs as a DOS application under Windows 9X, you can turn
on support for long file names. If you do that, Emacs doesn't truncate
file names or convert them to lower case; instead, it uses the file
names that you specify, verbatim. To enable long file name support,
set the environment variable `LFN' to `y' before starting Emacs.
Unfortunately, Windows NT doesn't allow DOS programs to access long
file names, so Emacs built for MS-DOS will only see their short 8+3
aliases.
MS-DOS has no notion of home directory, so Emacs on MS-DOS pretends
that the directory where it is installed is the value of `HOME'
environment variable. That is, if your Emacs binary, `emacs.exe', is
in the directory `c:/utils/emacs/bin', then Emacs acts as if `HOME'
were set to `c:/utils/emacs'. In particular, that is where Emacs looks
for the init file `_emacs'. With this in mind, you can use `~' in file
names as an alias for the home directory, as you would in Unix. You
can also set `HOME' variable in the environment before starting Emacs;
its value will then override the above default behavior.
Emacs on MS-DOS handles the directory name `/dev' specially, because
of a feature in the emulator libraries of DJGPP that pretends I/O
devices have names in that directory. We recommend that you avoid
using an actual directory named `/dev' on any disk.
Text Files and Binary Files
===========================
GNU Emacs uses newline characters to separate text lines. This is
the convention used on Unix, on which GNU Emacs was developed, and on
GNU systems since they are modeled on Unix.
MS-DOS and MS-Windows normally use carriage-return linefeed, a
two-character sequence, to separate text lines. (Linefeed is the same
character as newline.) Therefore, convenient editing of typical files
with Emacs requires conversion of these end-of-line (EOL) sequences.
And that is what Emacs normally does: it converts carriage-return
linefeed into newline when reading files, and converts newline into
carriage-return linefeed when writing files. The same mechanism that
handles conversion of international character codes does this conversion
also (*note Coding Systems::.).
One consequence of this special format-conversion of most files is
that character positions as reported by Emacs (*note Position Info::.)
do not agree with the file size information known to the operating
system.
Some kinds of files should not be converted, because their contents
are not really text. Therefore, Emacs on MS-DOS distinguishes certain
files as "binary files", and reads and writes them verbatim. (This
distinction is not part of MS-DOS; it is made by Emacs only.) These
include executable programs, compressed archives, etc. Emacs uses the
file name to decide whether to treat a file as binary: the variable
`file-name-buffer-file-type-alist' defines the file-name patterns that
indicate binary files. Note that if a file name matches one of the
patterns for binary files in `file-name-buffer-file-type-alist', Emacs
uses the `no-conversion' coding system (*note Coding Systems::.) which
turns off *all* coding-system conversions, not only the EOL conversion.
In addition, if Emacs recognizes from a file's contents that it uses
newline rather than carriage-return linefeed as its line separator, it
does not perform conversion when reading or writing that file. Thus,
you can read and edit files from Unix or GNU systems on MS-DOS with no
special effort, and they will be left with their Unix-style EOLs.
You can visit a file and specify whether to treat a file as text or
binary using the commands `find-file-text' and `find-file-binary'.
End-of-line conversion is part of the general coding system conversion
mechanism, so another way to control whether to treat a file as text or
binary is with the commands for specifying a coding system (*note
Specify Coding::.). For example, `C-x <RET> c undecided-unix <RET> C-x
C-f foobar.txt' visits the file `foobar.txt' without converting the
EOLs.
The mode line indicates whether end-of-line translation was used for
the current buffer. Normally a colon appears after the coding system
letter near the beginning of the mode line. If MS-DOS end-of-line
translation is in use for the buffer, this character changes to a
backslash.
When you use NFS or Samba to access file systems that reside on
computers using Unix or GNU systems, Emacs should not perform
end-of-line translation on any files in these file systems-not even
when you create a new file. To request this, designate these file
systems as "untranslated" file systems by calling the function
`add-untranslated-filesystem'. It takes one argument: the file system
name, including a drive letter and optionally a directory. For example,
(add-untranslated-filesystem "Z:")
designates drive Z as an untranslated file system, and
(add-untranslated-filesystem "Z:\\foo")
designates directory `\foo' on drive Z as an untranslated file system.
Most often you would use `add-untranslated-filesystem' in your
`_emacs' file, or in `site-start.el' so that all the users at your site
get the benefit of it.
To countermand the effect of `add-untranslated-filesystem', use the
function `remove-untranslated-filesystem'. This function takes one
argument, which should be a string just like the one that was used
previously with `add-untranslated-filesystem'.
Printing and MS-DOS
===================
Printing commands, such as `lpr-buffer' (*note Hardcopy::.) and
`ps-print-buffer' (*note Postscript::.) can work in MS-DOS and
MS-Windows by sending the output to one of the printer ports, if a
Unix-style `lpr' program is unavailable. This behaviour is controlled
by the same variables that control printing with `lpr' on Unix (*note
Hardcopy::., *note Postscript Variables::.), but the defaults for these
variables on MS-DOS and MS-Windows are not the same as the defaults on
Unix.
If you want to use your local printer, printing on it in the usual
DOS manner, then set the Lisp variable `lpr-command' to `""' (its
default value) and `printer-name' to the name of the printer port--for
example, `"PRN"', the usual local printer port (that's the default), or
`"LPT2"', or `"COM1"' for a serial printer. You can also set
`printer-name' to a file name, in which case "printed" output is
actually appended to that file. If you set `printer-name' to `"NUL"',
printed output is silently discarded (sent to the system null device).
On MS-Windows, when the Windows network software is installed, you
can also use a printer shared by another machine by setting
`printer-name' to the UNC share name for that printer-for example,
`"//joes_pc/hp4si"'. (It doesn't matter whether you use forward
slashes or backslashes here.) To find out the names of shared printers,
run the command `net view' at a DOS command prompt to obtain a list of
servers, and `net view SERVER-NAME' to see the names of printers (and
directories) shared by that server.
If you set `printer-name' to a file name, it's best to use an
absolute file name. Emacs changes the working directory according to
the default directory of the current buffer, so if the file name in
`printer-name' is relative, you will end up with several such files,
each one in the directory of the buffer from which the printing was
done.
The commands `print-buffer' and `print-region' call the `pr'
program, or use special switches to the `lpr' program, to produce
headers on each printed page. MS-DOS and MS-Windows don't normally
have these programs, so by default, the variable `lpr-headers-switches'
is set so that the requests to print page headers are silently ignored.
Thus, `print-buffer' and `print-region' produce the same output as
`lpr-buffer' and `lpr-region', respectively. If you do have a suitable
`pr' program (for example, from GNU Textutils), set
`lpr-headers-switches' to `nil'; Emacs will then call `pr' to produce
the page headers, and print the resulting output as specified by
`printer-name'.
Finally, if you do have an `lpr' work-alike, you can set the
variable `lpr-command' to `"lpr"'. Then Emacs will use `lpr' for
printing, as on other systems. (If the name of the program isn't
`lpr', set `lpr-command' to specify where to find it.) The variable
`lpr-switches' has its standard meaning when `lpr-command' is not `""'.
If the variable `printer-name' has a string value, it is used as the
value for the `-P' option to `lpr', as on Unix.
A parallel set of variables, `ps-lpr-command', `ps-lpr-switches',
and `ps-printer-name' (*note Postscript Variables::.), defines how
PostScript files should be printed. These variables are used in the
same way as the corresponding variables described above for
non-PostScript printing. Thus, the value of `ps-printer-name' is used
as the name of the device (or file) to which PostScript output is sent,
just as `printer-name' is used for non-PostScript printing. (There are
two distinct sets of variables in case you have two printers attached
to two different ports, and only one of them is a PostScript printer.)
The default value of the variable `ps-lpr-command' is `""', which
causes PostScript output to be sent to the printer port specified by
`ps-printer-name', but `ps-lpr-command' can also be set to the name of
a program which will accept PostScript files. Thus, if you have a
non-PostScript printer, you can set this variable to the name of a
PostScript interpreter program (such as Ghostscript). Any switches
that need to be passed to the interpreter program are specified using
`ps-lpr-switches'. (If the value of `ps-printer-name' is a string, it
will be added to the list of switches as the value for the `-P' option.
This is probably only useful if you are using `lpr', so when using an
interpreter typically you would set `ps-printer-name' to something
other than a string so it is ignored.)
For example, to use Ghostscript for printing on an Epson printer
connected to the `LPT2' port, put this in your `_emacs' file:
(setq ps-printer-name t) ; Ghostscript doesn't understand -P
(setq ps-lpr-command "c:/gs/gs386")
(setq ps-lpr-switches '("-q" "-dNOPAUSE"
"-sDEVICE=epson"
"-r240x72"
"-sOutputFile=LPT2"
"-Ic:/gs"))
(This assumes that Ghostscript is installed in the `"c:/gs"' directory.)
For backwards compatibility, the value of `dos-printer'
(`dos-ps-printer'), if it has a value, overrides the value of
`printer-name' (`ps-printer-name'), on MS-DOS and MS-Windows only.
International Support on MS-DOS
===============================
Emacs on MS-DOS supports the same international character sets as it
does on Unix and other platforms (*note International::.), including
coding systems for converting between the different character sets.
However, due to incompatibilities between MS-DOS/MS-Windows and Unix,
there are several DOS-specific aspects of this support that users should
be aware of. This section describes these aspects.
`M-x dos-codepage-setup'
Set up Emacs display and coding systems as appropriate for the
current DOS codepage.
`M-x codepage-setup'
Create a coding system for a certain DOS codepage.
MS-DOS is designed to support one character set of 256 characters at
any given time, but gives you a variety of character sets to choose
from. The alternative character sets are known as "DOS codepages".
Each codepage includes all 128 ASCII characters, but the other 128
characters (codes 128 through 255) vary from one codepage to another.
Each DOS codepage is identified by a 3-digit number, such as 850, 862,
etc.
In contrast to X Windows, which lets you use several fonts at the
same time, MS-DOS doesn't allow use of several codepages in a single
session. Instead, MS-DOS loads a single codepage at system startup,
and you must reboot MS-DOS to change it(1). Much the same limitation
applies when you run DOS executables on other systems such as
MS-Windows.
If you invoke Emacs on MS-DOS with the `--unibyte' option (*note
Initial Options::.), Emacs does not perform any conversion of non-ASCII
characters. Instead, it reads and writes any non-ASCII characters
verbatim, and sends their 8-bit codes to the display verbatim. Thus,
unibyte Emacs on MS-DOS supports the current codepage, whatever it may
be, but cannot even represent any other characters.
For multibyte operation on MS-DOS, Emacs needs to know which
characters the chosen DOS codepage can display. So it queries the
system shortly after startup to get the chosen codepage number, and
stores the number in the variable `dos-codepage'. Some systems return
the default value 437 for the current codepage, even though the actual
codepage is different. (This typically happens when you use the
codepage built into the display hardware.) You can specify a different
codepage for Emacs to use by setting the variable `dos-codepage' in
your init file.
Multibyte Emacs supports only certain DOS codepages: those which can
display Far-Eastern scripts, like the Japanese codepage 932, and those
that encode a single ISO 8859 character set.
The Far-Eastern codepages can directly display one of the MULE
character sets for these countries, so Emacs simply sets up to use the
appropriate terminal coding system that is supported by the codepage.
The special features described in the rest of this section mostly
pertain to codepages that encode ISO 8859 character sets.
For the codepages which correspond to one of the ISO character sets,
Emacs knows the character set name based on the codepage number. Emacs
automatically creates a coding system to support reading and writing
files that use the current codepage, and uses this coding system by
default. The name of this coding system is `cpNNN', where NNN is the
codepage number.(2)
All the `cpNNN' coding systems use the letter `D' (for "DOS") as
their mode-line mnemonic. Since both the terminal coding system and
the default coding system for file I/O are set to the proper `cpNNN'
coding system at startup, it is normal for the mode line on MS-DOS to
begin with `-DD\-'. *Note Mode Line::. Far-Eastern DOS terminals do
not use the `cpNNN' coding systems, and thus their initial mode line
looks like on Unix.
Since the codepage number also indicates which script you are using,
Emacs automatically runs `set-language-environment' to select the
language environment for that script (*note Language Environments::.).
If a buffer contains a character belonging to some other ISO 8859
character set, not the one that the chosen DOS codepage supports, Emacs
displays it using a sequence of ASCII characters. For example, if the
current codepage doesn't have a glyph for the letter ``o' (small `o'
with a grave accent), it is displayed as `{`o}', where the braces serve
as a visual indication that this is a single character. (This may look
awkward for some non-Latin characters, such as those from Greek or
Hebrew alphabets, but it is still readable by a person who knows the
language.) Even though the character may occupy several columns on the
screen, it is really still just a single character, and all Emacs
commands treat it as one.
Not all characters in DOS codepages correspond to ISO 8859
characters--some are used for other purposes, such as box-drawing
characters and other graphics. Emacs cannot represent these characters
internally, so when you read a file that uses these characters, they are
converted into a particular character code, specified by the variable
`dos-unsupported-character-glyph'.
Emacs supports many other characters sets aside from ISO 8859, but it
cannot display them on MS-DOS. So if one of these multibyte characters
appears in a buffer, Emacs on MS-DOS displays them as specified by the
`dos-unsupported-character-glyph' variable; by default, this glyph is
an empty triangle. Use the `C-u C-x =' command to display the actual
code and character set of such characters. *Note Position Info::.
By default, Emacs defines a coding system to support the current
codepage. To define a coding system for some other codepage (e.g., to
visit a file written on a DOS machine in another country), use the `M-x
codepage-setup' command. It prompts for the 3-digit code of the
codepage, with completion, then creates the coding system for the
specified codepage. You can then use the new coding system to read and
write files, but you must specify it explicitly for the file command
when you want to use it (*note Specify Coding::.).
These coding systems are also useful for visiting a file encoded
using a DOS codepage, using Emacs running on some other operating
system.
---------- Footnotes ----------
(1) Normally, one particular codepage is burnt into the display
memory, while other codepages can be installed by modifying system
configuration files, such as `CONFIG.SYS', and rebooting.
(2) The standard Emacs coding systems for ISO 8859 are not quite
right for the purpose, because typically the DOS codepage does not
match the standard ISO character codes. For example, the letter `c,'
(`c' with cedilla) has code 231 in the standard Latin-1 character set,
but the corresponding DOS codepage 850 uses code 135 for this glyph.
Subprocesses on MS-DOS
======================
Because MS-DOS is a single-process "operating system," asynchronous
subprocesses are not available. In particular, Shell mode and its
variants do not work. Most Emacs features that use asynchronous
subprocesses also don't work on MS-DOS, including spelling correction
and GUD. When in doubt, try and see; commands that don't work print an
error message saying that asynchronous processes aren't supported.
Compilation under Emacs with `M-x compile', searching files with
`M-x grep' and displaying differences between files with `M-x diff' do
work, by running the inferior processes synchronously. This means you
cannot do any more editing until the inferior process finishes.
By contrast, Emacs compiled as native Windows application *does*
support asynchronous subprocesses. *Note Windows Processes::.
Printing commands, such as `lpr-buffer' (*note Hardcopy::.) and
`ps-print-buffer' (*note Postscript::.), work in MS-DOS by sending the
output to one of the printer ports. *Note MS-DOS Printing::.
When you run a subprocess synchronously on MS-DOS, make sure the
program terminates and does not try to read keyboard input. If the
program does not terminate on its own, you will be unable to terminate
it, because MS-DOS provides no general way to terminate a process.
Pressing `C-c' or `C-<BREAK>' might sometimes help in these cases.
Accessing files on other machines is not supported on MS-DOS. Other
network-oriented commands such as sending mail, Web browsing, remote
login, etc., don't work either, unless network access is built into
MS-DOS with some network redirector.
Dired on MS-DOS uses the `ls-lisp' package where other platforms use
the system `ls' command. Therefore, Dired on MS-DOS supports only some
of the possible options you can mention in the `dired-listing-switches'
variable. The options that work are `-A', `-a', `-c', `-i', `-r', `-S',
`-s', `-t', and `-u'.
Subprocesses on Windows 95 and NT
=================================
Emacs compiled as a native Windows application (as opposed to the DOS
version) includes full support for asynchronous subprocesses. In the
Windows version, synchronous and asynchronous subprocesses work fine on
both Windows 95 and Windows NT as long as you run only 32-bit Windows
applications. However, when you run a DOS application in a subprocess,
you may encounter problems or be unable to run the application at all;
and if you run two DOS applications at the same time in two
subprocesses, you may have to reboot your system.
Since the standard command interpreter (and most command line
utilities) on Windows 95 are DOS applications, these problems are
significant when using that system. But there's nothing we can do
about them; only Microsoft can fix them.
If you run just one DOS application subprocess, the subprocess should
work as expected as long as it is "well-behaved" and does not perform
direct screen access or other unusual actions. If you have a CPU
monitor application, your machine will appear to be 100% busy even when
the DOS application is idle, but this is only an artifact of the way CPU
monitors measure processor load.
You must terminate the DOS application before you start any other DOS
application in a different subprocess. Emacs is unable to interrupt or
terminate a DOS subprocess. The only way you can terminate such a
subprocess is by giving it a command that tells its program to exit.
If you attempt to run two DOS applications at the same time in
separate subprocesses, the second one that is started will be suspended
until the first one finishes, even if either or both of them are
asynchronous.
If you can go to the first subprocess, and tell it to exit, the
second subprocess should continue normally. However, if the second
subprocess is synchronous, Emacs itself will be hung until the first
subprocess finishes. If it will not finish without user input, then
you have no choice but to reboot if you are running on Windows 95. If
you are running on Windows NT, you can use a process viewer application
to kill the appropriate instance of ntvdm instead (this will terminate
both DOS subprocesses).
If you have to reboot Windows 95 in this situation, do not use the
`Shutdown' command on the `Start' menu; that usually hangs the system.
Instead, type `CTL-ALT-<DEL>' and then choose `Shutdown'. That usually
works, although it may take a few minutes to do its job.
Using the System Menu on Windows
================================
Emacs compiled as a native Windows application normally turns off the
Windows feature that tapping the <ALT> key invokes the Windows menu.
The reason is that the <ALT> also serves as <META> in Emacs. When
using Emacs, users often press the <META> key temporarily and then
change their minds; if this has the effect of bringing up the Windows
menu, it alters the meaning of subsequent commands. Many users find
this frustrating.
You can reenable Windows's default handling of tapping the <ALT> key
by setting `w32-pass-alt-to-system' to a non-`nil' value.
The GNU Manifesto
*****************
The GNU Manifesto which appears below was written by Richard
Stallman at the beginning of the GNU project, to ask for
participation and support. For the first few years, it was
updated in minor ways to account for developments, but now it
seems best to leave it unchanged as most people have seen it.
Since that time, we have learned about certain common
misunderstandings that different wording could help avoid.
Footnotes added in 1993 help clarify these points.
For up-to-date information about the available GNU software,
please see the latest issue of the GNU's Bulletin. The list is
much too long to include here.
What's GNU? Gnu's Not Unix!
============================
GNU, which stands for Gnu's Not Unix, is the name for the complete
Unix-compatible software system which I am writing so that I can give it
away free to everyone who can use it.(1) Several other volunteers are
helping me. Contributions of time, money, programs and equipment are
greatly needed.
So far we have an Emacs text editor with Lisp for writing editor
commands, a source level debugger, a yacc-compatible parser generator,
a linker, and around 35 utilities. A shell (command interpreter) is
nearly completed. A new portable optimizing C compiler has compiled
itself and may be released this year. An initial kernel exists but
many more features are needed to emulate Unix. When the kernel and
compiler are finished, it will be possible to distribute a GNU system
suitable for program development. We will use TeX as our text
formatter, but an nroff is being worked on. We will use the free,
portable X window system as well. After this we will add a portable
Common Lisp, an Empire game, a spreadsheet, and hundreds of other
things, plus on-line documentation. We hope to supply, eventually,
everything useful that normally comes with a Unix system, and more.
GNU will be able to run Unix programs, but will not be identical to
Unix. We will make all improvements that are convenient, based on our
experience with other operating systems. In particular, we plan to
have longer file names, file version numbers, a crashproof file system,
file name completion perhaps, terminal-independent display support, and
perhaps eventually a Lisp-based window system through which several
Lisp programs and ordinary Unix programs can share a screen. Both C
and Lisp will be available as system programming languages. We will
try to support UUCP, MIT Chaosnet, and Internet protocols for
communication.
GNU is aimed initially at machines in the 68000/16000 class with
virtual memory, because they are the easiest machines to make it run
on. The extra effort to make it run on smaller machines will be left
to someone who wants to use it on them.
To avoid horrible confusion, please pronounce the `G' in the word
`GNU' when it is the name of this project.
Why I Must Write GNU
====================
I consider that the golden rule requires that if I like a program I
must share it with other people who like it. Software sellers want to
divide the users and conquer them, making each user agree not to share
with others. I refuse to break solidarity with other users in this
way. I cannot in good conscience sign a nondisclosure agreement or a
software license agreement. For years I worked within the Artificial
Intelligence Lab to resist such tendencies and other inhospitalities,
but eventually they had gone too far: I could not remain in an
institution where such things are done for me against my will.
So that I can continue to use computers without dishonor, I have
decided to put together a sufficient body of free software so that I
will be able to get along without any software that is not free. I
have resigned from the AI lab to deny MIT any legal excuse to prevent
me from giving GNU away.
Why GNU Will Be Compatible with Unix
====================================
Unix is not my ideal system, but it is not too bad. The essential
features of Unix seem to be good ones, and I think I can fill in what
Unix lacks without spoiling them. And a system compatible with Unix
would be convenient for many other people to adopt.
How GNU Will Be Available
=========================
GNU is not in the public domain. Everyone will be permitted to
modify and redistribute GNU, but no distributor will be allowed to
restrict its further redistribution. That is to say, proprietary
modifications will not be allowed. I want to make sure that all
versions of GNU remain free.
Why Many Other Programmers Want to Help
=======================================
I have found many other programmers who are excited about GNU and
want to help.
Many programmers are unhappy about the commercialization of system
software. It may enable them to make more money, but it requires them
to feel in conflict with other programmers in general rather than feel
as comrades. The fundamental act of friendship among programmers is the
sharing of programs; marketing arrangements now typically used
essentially forbid programmers to treat others as friends. The
purchaser of software must choose between friendship and obeying the
law. Naturally, many decide that friendship is more important. But
those who believe in law often do not feel at ease with either choice.
They become cynical and think that programming is just a way of making
money.
By working on and using GNU rather than proprietary programs, we can
be hospitable to everyone and obey the law. In addition, GNU serves as
an example to inspire and a banner to rally others to join us in
sharing. This can give us a feeling of harmony which is impossible if
we use software that is not free. For about half the programmers I
talk to, this is an important happiness that money cannot replace.
How You Can Contribute
======================
I am asking computer manufacturers for donations of machines and
money. I'm asking individuals for donations of programs and work.
One consequence you can expect if you donate machines is that GNU
will run on them at an early date. The machines should be complete,
ready to use systems, approved for use in a residential area, and not
in need of sophisticated cooling or power.
I have found very many programmers eager to contribute part-time
work for GNU. For most projects, such part-time distributed work would
be very hard to coordinate; the independently-written parts would not
work together. But for the particular task of replacing Unix, this
problem is absent. A complete Unix system contains hundreds of utility
programs, each of which is documented separately. Most interface
specifications are fixed by Unix compatibility. If each contributor
can write a compatible replacement for a single Unix utility, and make
it work properly in place of the original on a Unix system, then these
utilities will work right when put together. Even allowing for Murphy
to create a few unexpected problems, assembling these components will
be a feasible task. (The kernel will require closer communication and
will be worked on by a small, tight group.)
If I get donations of money, I may be able to hire a few people full
or part time. The salary won't be high by programmers' standards, but
I'm looking for people for whom building community spirit is as
important as making money. I view this as a way of enabling dedicated
people to devote their full energies to working on GNU by sparing them
the need to make a living in another way.
Why All Computer Users Will Benefit
===================================
Once GNU is written, everyone will be able to obtain good system
software free, just like air.(2)
This means much more than just saving everyone the price of a Unix
license. It means that much wasteful duplication of system programming
effort will be avoided. This effort can go instead into advancing the
state of the art.
Complete system sources will be available to everyone. As a result,
a user who needs changes in the system will always be free to make them
himself, or hire any available programmer or company to make them for
him. Users will no longer be at the mercy of one programmer or company
which owns the sources and is in sole position to make changes.
Schools will be able to provide a much more educational environment
by encouraging all students to study and improve the system code.
Harvard's computer lab used to have the policy that no program could be
installed on the system if its sources were not on public display, and
upheld it by actually refusing to install certain programs. I was very
much inspired by this.
Finally, the overhead of considering who owns the system software
and what one is or is not entitled to do with it will be lifted.
Arrangements to make people pay for using a program, including
licensing of copies, always incur a tremendous cost to society through
the cumbersome mechanisms necessary to figure out how much (that is,
which programs) a person must pay for. And only a police state can
force everyone to obey them. Consider a space station where air must
be manufactured at great cost: charging each breather per liter of air
may be fair, but wearing the metered gas mask all day and all night is
intolerable even if everyone can afford to pay the air bill. And the
TV cameras everywhere to see if you ever take the mask off are
outrageous. It's better to support the air plant with a head tax and
chuck the masks.
Copying all or parts of a program is as natural to a programmer as
breathing, and as productive. It ought to be as free.
Some Easily Rebutted Objections to GNU's Goals
==============================================
"Nobody will use it if it is free, because that means they can't
rely on any support."
"You have to charge for the program to pay for providing the
support."
If people would rather pay for GNU plus service than get GNU free
without service, a company to provide just service to people who have
obtained GNU free ought to be profitable.(3)
We must distinguish between support in the form of real programming
work and mere handholding. The former is something one cannot rely on
from a software vendor. If your problem is not shared by enough
people, the vendor will tell you to get lost.
If your business needs to be able to rely on support, the only way
is to have all the necessary sources and tools. Then you can hire any
available person to fix your problem; you are not at the mercy of any
individual. With Unix, the price of sources puts this out of
consideration for most businesses. With GNU this will be easy. It is
still possible for there to be no available competent person, but this
problem cannot be blamed on distribution arrangements. GNU does not
eliminate all the world's problems, only some of them.
Meanwhile, the users who know nothing about computers need
handholding: doing things for them which they could easily do
themselves but don't know how.
Such services could be provided by companies that sell just
hand-holding and repair service. If it is true that users would rather
spend money and get a product with service, they will also be willing
to buy the service having got the product free. The service companies
will compete in quality and price; users will not be tied to any
particular one. Meanwhile, those of us who don't need the service
should be able to use the program without paying for the service.
"You cannot reach many people without advertising, and you must
charge for the program to support that."
"It's no use advertising a program people can get free."
There are various forms of free or very cheap publicity that can be
used to inform numbers of computer users about something like GNU. But
it may be true that one can reach more microcomputer users with
advertising. If this is really so, a business which advertises the
service of copying and mailing GNU for a fee ought to be successful
enough to pay for its advertising and more. This way, only the users
who benefit from the advertising pay for it.
On the other hand, if many people get GNU from their friends, and
such companies don't succeed, this will show that advertising was not
really necessary to spread GNU. Why is it that free market advocates
don't want to let the free market decide this?(4)
"My company needs a proprietary operating system to get a
competitive edge."
GNU will remove operating system software from the realm of
competition. You will not be able to get an edge in this area, but
neither will your competitors be able to get an edge over you. You and
they will compete in other areas, while benefiting mutually in this
one. If your business is selling an operating system, you will not
like GNU, but that's tough on you. If your business is something else,
GNU can save you from being pushed into the expensive business of
selling operating systems.
I would like to see GNU development supported by gifts from many
manufacturers and users, reducing the cost to each.(5)
"Don't programmers deserve a reward for their creativity?"
If anything deserves a reward, it is social contribution.
Creativity can be a social contribution, but only in so far as society
is free to use the results. If programmers deserve to be rewarded for
creating innovative programs, by the same token they deserve to be
punished if they restrict the use of these programs.
"Shouldn't a programmer be able to ask for a reward for his
creativity?"
There is nothing wrong with wanting pay for work, or seeking to
maximize one's income, as long as one does not use means that are
destructive. But the means customary in the field of software today
are based on destruction.
Extracting money from users of a program by restricting their use of
it is destructive because the restrictions reduce the amount and the
ways that the program can be used. This reduces the amount of wealth
that humanity derives from the program. When there is a deliberate
choice to restrict, the harmful consequences are deliberate destruction.
The reason a good citizen does not use such destructive means to
become wealthier is that, if everyone did so, we would all become
poorer from the mutual destructiveness. This is Kantian ethics; or,
the Golden Rule. Since I do not like the consequences that result if
everyone hoards information, I am required to consider it wrong for one
to do so. Specifically, the desire to be rewarded for one's creativity
does not justify depriving the world in general of all or part of that
creativity.
"Won't programmers starve?"
I could answer that nobody is forced to be a programmer. Most of us
cannot manage to get any money for standing on the street and making
faces. But we are not, as a result, condemned to spend our lives
standing on the street making faces, and starving. We do something
else.
But that is the wrong answer because it accepts the questioner's
implicit assumption: that without ownership of software, programmers
cannot possibly be paid a cent. Supposedly it is all or nothing.
The real reason programmers will not starve is that it will still be
possible for them to get paid for programming; just not paid as much as
now.
Restricting copying is not the only basis for business in software.
It is the most common basis because it brings in the most money. If it
were prohibited, or rejected by the customer, software business would
move to other bases of organization which are now used less often.
There are always numerous ways to organize any kind of business.
Probably programming will not be as lucrative on the new basis as it
is now. But that is not an argument against the change. It is not
considered an injustice that sales clerks make the salaries that they
now do. If programmers made the same, that would not be an injustice
either. (In practice they would still make considerably more than
that.)
"Don't people have a right to control how their creativity is
used?"
"Control over the use of one's ideas" really constitutes control over
other people's lives; and it is usually used to make their lives more
difficult.
People who have studied the issue of intellectual property rights
carefully (such as lawyers) say that there is no intrinsic right to
intellectual property. The kinds of supposed intellectual property
rights that the government recognizes were created by specific acts of
legislation for specific purposes.
For example, the patent system was established to encourage
inventors to disclose the details of their inventions. Its purpose was
to help society rather than to help inventors. At the time, the life
span of 17 years for a patent was short compared with the rate of
advance of the state of the art. Since patents are an issue only among
manufacturers, for whom the cost and effort of a license agreement are
small compared with setting up production, the patents often do not do
much harm. They do not obstruct most individuals who use patented
products.
The idea of copyright did not exist in ancient times, when authors
frequently copied other authors at length in works of non-fiction. This
practice was useful, and is the only way many authors' works have
survived even in part. The copyright system was created expressly for
the purpose of encouraging authorship. In the domain for which it was
invented--books, which could be copied economically only on a printing
press--it did little harm, and did not obstruct most of the individuals
who read the books.
All intellectual property rights are just licenses granted by society
because it was thought, rightly or wrongly, that society as a whole
would benefit by granting them. But in any particular situation, we
have to ask: are we really better off granting such license? What kind
of act are we licensing a person to do?
The case of programs today is very different from that of books a
hundred years ago. The fact that the easiest way to copy a program is
from one neighbor to another, the fact that a program has both source
code and object code which are distinct, and the fact that a program is
used rather than read and enjoyed, combine to create a situation in
which a person who enforces a copyright is harming society as a whole
both materially and spiritually; in which a person should not do so
regardless of whether the law enables him to.
"Competition makes things get done better."
The paradigm of competition is a race: by rewarding the winner, we
encourage everyone to run faster. When capitalism really works this
way, it does a good job; but its defenders are wrong in assuming it
always works this way. If the runners forget why the reward is offered
and become intent on winning, no matter how, they may find other
strategies--such as, attacking other runners. If the runners get into
a fist fight, they will all finish late.
Proprietary and secret software is the moral equivalent of runners
in a fist fight. Sad to say, the only referee we've got does not seem
to object to fights; he just regulates them ("For every ten yards you
run, you can fire one shot"). He really ought to break them up, and
penalize runners for even trying to fight.
"Won't everyone stop programming without a monetary incentive?"
Actually, many people will program with absolutely no monetary
incentive. Programming has an irresistible fascination for some
people, usually the people who are best at it. There is no shortage of
professional musicians who keep at it even though they have no hope of
making a living that way.
But really this question, though commonly asked, is not appropriate
to the situation. Pay for programmers will not disappear, only become
less. So the right question is, will anyone program with a reduced
monetary incentive? My experience shows that they will.
For more than ten years, many of the world's best programmers worked
at the Artificial Intelligence Lab for far less money than they could
have had anywhere else. They got many kinds of non-monetary rewards:
fame and appreciation, for example. And creativity is also fun, a
reward in itself.
Then most of them left when offered a chance to do the same
interesting work for a lot of money.
What the facts show is that people will program for reasons other
than riches; but if given a chance to make a lot of money as well, they
will come to expect and demand it. Low-paying organizations do poorly
in competition with high-paying ones, but they do not have to do badly
if the high-paying ones are banned.
"We need the programmers desperately. If they demand that we stop
helping our neighbors, we have to obey."
You're never so desperate that you have to obey this sort of demand.
Remember: millions for defense, but not a cent for tribute!
"Programmers need to make a living somehow."
In the short run, this is true. However, there are plenty of ways
that programmers could make a living without selling the right to use a
program. This way is customary now because it brings programmers and
businessmen the most money, not because it is the only way to make a
living. It is easy to find other ways if you want to find them. Here
are a number of examples.
A manufacturer introducing a new computer will pay for the porting of
operating systems onto the new hardware.
The sale of teaching, hand-holding and maintenance services could
also employ programmers.
People with new ideas could distribute programs as freeware, asking
for donations from satisfied users, or selling hand-holding services.
I have met people who are already working this way successfully.
Users with related needs can form users' groups, and pay dues. A
group would contract with programming companies to write programs that
the group's members would like to use.
All sorts of development can be funded with a Software Tax:
Suppose everyone who buys a computer has to pay x percent of the
price as a software tax. The government gives this to an agency
like the NSF to spend on software development.
But if the computer buyer makes a donation to software development
himself, he can take a credit against the tax. He can donate to
the project of his own choosing--often, chosen because he hopes to
use the results when it is done. He can take a credit for any
amount of donation up to the total tax he had to pay.
The total tax rate could be decided by a vote of the payers of the
tax, weighted according to the amount they will be taxed on.
The consequences:
* The computer-using community supports software development.
* This community decides what level of support is needed.
* Users who care which projects their share is spent on can
choose this for themselves.
In the long run, making programs free is a step toward the
post-scarcity world, where nobody will have to work very hard just to
make a living. People will be free to devote themselves to activities
that are fun, such as programming, after spending the necessary ten
hours a week on required tasks such as legislation, family counseling,
robot repair and asteroid prospecting. There will be no need to be
able to make a living from programming.
We have already greatly reduced the amount of work that the whole
society must do for its actual productivity, but only a little of this
has translated itself into leisure for workers because much
nonproductive activity is required to accompany productive activity.
The main causes of this are bureaucracy and isometric struggles against
competition. Free software will greatly reduce these drains in the
area of software production. We must do this, in order for technical
gains in productivity to translate into less work for us.
---------- Footnotes ----------
(1) The wording here was careless. The intention was that nobody
would have to pay for *permission* to use the GNU system. But the
words don't make this clear, and people often interpret them as saying
that copies of GNU should always be distributed at little or no charge.
That was never the intent; later on, the manifesto mentions the
possibility of companies providing the service of distribution for a
profit. Subsequently I have learned to distinguish carefully between
"free" in the sense of freedom and "free" in the sense of price. Free
software is software that users have the freedom to distribute and
change. Some users may obtain copies at no charge, while others pay to
obtain copies--and if the funds help support improving the software, so
much the better. The important thing is that everyone who has a copy
has the freedom to cooperate with others in using it.
(2) This is another place I failed to distinguish carefully between
the two different meanings of "free". The statement as it stands is
not false--you can get copies of GNU software at no charge, from your
friends or over the net. But it does suggest the wrong idea.
(3) Several such companies now exist.
(4) The Free Software Foundation raises most of its funds from a
distribution service, although it is a charity rather than a company.
If *no one* chooses to obtain copies by ordering from the FSF, it will
be unable to do its work. But this does not mean that proprietary
restrictions are justified to force every user to pay. If a small
fraction of all the users order copies from the FSF, that is sufficient
to keep the FSF afloat. So we ask users to choose to support us in
this way. Have you done your part?
(5) A group of computer companies recently pooled funds to support
maintenance of the GNU C Compiler.
Glossary
********
Abbrev
An abbrev is a text string which expands into a different text
string when present in the buffer. For example, you might define
a few letters as an abbrev for a long phrase that you want to
insert frequently. *Note Abbrevs::.
Aborting
Aborting means getting out of a recursive edit (q.v.). The
commands `C-]' and `M-x top-level' are used for this. *Note
Quitting::.
Alt
Alt is the name of a modifier bit which a keyboard input character
may have. To make a character Alt, type it while holding down the
<ALT> key. Such characters are given names that start with `Alt-'
(usually written `A-' for short). (Note that many terminals have a
key labeled <ALT> which is really a <META> key.) *Note Alt: User
Input.
ASCII character
An ASCII character is either an ASCII control character or an ASCII
printing character. *Note User Input::.
ASCII control character
An ASCII control character is the Control version of an upper-case
letter, or the Control version of one of the characters `@[\]^_?'.
ASCII printing character
ASCII printing characters include letters, digits, space, and these
punctuation characters: `!@#$%^& *()_-+=|\~` {}[]:;"' <>,.?/'.
Auto Fill Mode
Auto Fill mode is a minor mode in which text that you insert is
automatically broken into lines of fixed width. *Note Filling::.
Auto Saving
Auto saving is the practice of saving the contents of an Emacs
buffer in a specially-named file, so that the information will not
be lost if the buffer is lost due to a system error or user error.
*Note Auto Save::.
Backup File
A backup file records the contents that a file had before the
current editing session. Emacs makes backup files automatically
to help you track down or cancel changes you later regret making.
*Note Backup::.
Balance Parentheses
Emacs can balance parentheses manually or automatically. Manual
balancing is done by the commands to move over balanced expressions
(*note Lists::.). Automatic balancing is done by blinking or
highlighting the parenthesis that matches one just inserted (*note
Matching Parens: Matching.).
Bind
To bind a key sequence means to give it a binding (q.v.). *Note
Rebinding::.
Binding
A key sequence gets its meaning in Emacs by having a binding,
which is a command (q.v.), a Lisp function that is run when the
user types that sequence. *Note Binding: Commands. Customization
often involves rebinding a character to a different command
function. The bindings of all key sequences are recorded in the
keymaps (q.v.). *Note Keymaps::.
Blank Lines
Blank lines are lines that contain only whitespace. Emacs has
several commands for operating on the blank lines in the buffer.
Buffer
The buffer is the basic editing unit; one buffer corresponds to
one text being edited. You can have several buffers, but at any
time you are editing only one, the `selected' buffer, though
several can be visible when you are using multiple windows (q.v.).
Most buffers are visiting (q.v.) some file. *Note Buffers::.
Buffer Selection History
Emacs keeps a buffer selection history which records how recently
each Emacs buffer has been selected. This is used for choosing a
buffer to select. *Note Buffers::.
Button Down Event
A button down event is the kind of input event generated right
away when you press a mouse button. *Note Mouse Buttons::.
`C-'
`C-' in the name of a character is an abbreviation for Control.
*Note C-: User Input.
`C-M-'
`C-M-' in the name of a character is an abbreviation for
Control-Meta. *Note C-M-: User Input.
Case Conversion
Case conversion means changing text from upper case to lower case
or vice versa. *Note Case::, for the commands for case conversion.
Character
Characters form the contents of an Emacs buffer; see *Note Text
Characters::. Also, key sequences (q.v.) are usually made up of
characters (though they may include other input events as well).
*Note User Input::.
Character Set
Emacs supports a number of character sets, each of which
represents a particular alphabet or script. *Note International::.
Click Event
A click event is the kind of input event generated when you press a
mouse button and release it without moving the mouse. *Note Mouse
Buttons::.
Coding System
A coding system is an encoding for representing text characters in
a file or in a stream of information. Emacs has the ability to
convert text to or from a variety of coding systems when reading
or writing it. *Note Coding Systems::.
Command
A command is a Lisp function specially defined to be able to serve
as a key binding in Emacs. When you type a key sequence (q.v.),
its binding (q.v.) is looked up in the relevant keymaps (q.v.) to
find the command to run. *Note Commands::.
Command Name
A command name is the name of a Lisp symbol which is a command
(*note Commands::.). You can invoke any command by its name using
`M-x' (*note M-x::.).
Comment
A comment is text in a program which is intended only for humans
reading the program, and which is marked specially so that it will
be ignored when the program is loaded or compiled. Emacs offers
special commands for creating, aligning and killing comments.
*Note Comments::.
Compilation
Compilation is the process of creating an executable program from
source code. Emacs has commands for compiling files of Emacs Lisp
code (*note Byte Compilation: (elisp)Byte Compilation.) and
programs in C and other languages (*note Compilation::.).
Complete Key
A complete key is a key sequence which fully specifies one action
to be performed by Emacs. For example, `X' and `C-f' and `C-x m'
are complete keys. Complete keys derive their meanings from being
bound (q.v.) to commands (q.v.). Thus, `X' is conventionally
bound to a command to insert `X' in the buffer; `C-x m' is
conventionally bound to a command to begin composing a mail
message. *Note Keys::.
Completion
Completion is what Emacs does when it automatically fills out an
abbreviation for a name into the entire name. Completion is done
for minibuffer (q.v.) arguments when the set of possible valid
inputs is known; for example, on command names, buffer names, and
file names. Completion occurs when <TAB>, <SPC> or <RET> is
typed. *Note Completion::.
Continuation Line
When a line of text is longer than the width of the window, it
takes up more than one screen line when displayed. We say that the
text line is continued, and all screen lines used for it after the
first are called continuation lines. *Note Continuation: Basic.
Control Character
A control character is a character that you type by holding down
the <CTRL> key. Some control characters also have their own keys,
so that you can type them without using <CTRL>. For example,
<RET>, <TAB>, <ESC> and <DEL> are all control characters. *Note
User Input::.
Copyleft
A copyleft is a notice giving the public legal permission to
redistribute a program or other work of art. Copylefts are used by
left-wing programmers to promote freedom and cooperation, just as
copyrights are used by right-wing programmers to gain power over
other people.
The particular form of copyleft used by the GNU project is called
the GNU General Public License. *Note Copying::.
Current Buffer
The current buffer in Emacs is the Emacs buffer on which most
editing commands operate. You can select any Emacs buffer as the
current one. *Note Buffers::.
Current Line
The line point is on (*note Point::.).
Current Paragraph
The paragraph that point is in. If point is between paragraphs,
the current paragraph is the one that follows point. *Note
Paragraphs::.
Current Defun
The defun (q.v.) that point is in. If point is between defuns, the
current defun is the one that follows point. *Note Defuns::.
Cursor
The cursor is the rectangle on the screen which indicates the
position called point (q.v.) at which insertion and deletion takes
place. The cursor is on or under the character that follows
point. Often people speak of `the cursor' when, strictly
speaking, they mean `point'. *Note Cursor: Basic.
Customization
Customization is making minor changes in the way Emacs works. It
is often done by setting variables (*note Variables::.) or by
rebinding key sequences (*note Keymaps::.).
Default Argument
The default for an argument is the value that will be assumed if
you do not specify one. When the minibuffer is used to read an
argument, the default argument is used if you just type <RET>.
*Note Minibuffer::.
Default Directory
When you specify a file name that does not start with `/' or `~',
it is interpreted relative to the current buffer's default
directory. *Note Default Directory: Minibuffer File.
Defun
A defun is a list at the top level of parenthesis or bracket
structure in a program. It is so named because most such lists in
Lisp programs are calls to the Lisp function `defun'. *Note
Defuns::.
<DEL>
<DEL> is a character that runs the command to delete one character
of text. *Note DEL: Basic.
Deletion
Deletion means erasing text without copying it into the kill ring
(q.v.). The alternative is killing (q.v.). *Note Deletion:
Killing.
Deletion of Files
Deleting a file means erasing it from the file system. *Note Misc
File Ops::.
Deletion of Messages
Deleting a message means flagging it to be eliminated from your
mail file. Until you expunge (q.v.) the Rmail file, you can still
undelete the messages you have deleted. *Note Rmail Deletion::.
Deletion of Windows
Deleting a window means eliminating it from the screen. Other
windows expand to use up the space. The deleted window can never
come back, but no actual text is thereby lost. *Note Windows::.
Directory
File directories are named collections in the file system, within
which you can place individual files or subdirectories. *Note
Directories::.
Dired
Dired is the Emacs facility that displays the contents of a file
directory and allows you to "edit the directory," performing
operations on the files in the directory. *Note Dired::.
Disabled Command
A disabled command is one that you may not run without special
confirmation. The usual reason for disabling a command is that it
is confusing for beginning users. *Note Disabling::.
Down Event
Short for `button down event'.
Drag Event
A drag event is the kind of input event generated when you press a
mouse button, move the mouse, and then release the button. *Note
Mouse Buttons::.
Dribble File
A file into which Emacs writes all the characters that the user
types on the keyboard. Dribble files are used to make a record for
debugging Emacs bugs. Emacs does not make a dribble file unless
you tell it to. *Note Bugs::.
Echo Area
The echo area is the bottom line of the screen, used for echoing
the arguments to commands, for asking questions, and printing
brief messages (including error messages). The messages are
stored in the buffer `*Messages*' so you can review them later.
*Note Echo Area::.
Echoing
Echoing is acknowledging the receipt of commands by displaying
them (in the echo area). Emacs never echoes single-character key
sequences; longer key sequences echo only if you pause while
typing them.
Electric
We say that a character is electric if it is normally
self-inserting (q.v.), but the current major mode (q.v.) redefines
it to do something else as well. For example, some programming
language major modes define particular delimiter characters to
reindent the line or insert one or more newlines in addition to
self-insertion.
Error
An error occurs when an Emacs command cannot execute in the current
circumstances. When an error occurs, execution of the command
stops (unless the command has been programmed to do otherwise) and
Emacs reports the error by printing an error message (q.v.).
Type-ahead is discarded. Then Emacs is ready to read another
editing command.
Error Message
An error message is a single line of output displayed by Emacs
when the user asks for something impossible to do (such as,
killing text forward when point is at the end of the buffer).
They appear in the echo area, accompanied by a beep.
<ESC>
<ESC> is a character used as a prefix for typing Meta characters on
keyboards lacking a <META> key. Unlike the <META> key (which,
like the <SHIFT> key, is held down while another character is
typed), you press the <ESC> key as you would press a letter key,
and it applies to the next character you type.
Expunging
Expunging an Rmail file or Dired buffer is an operation that truly
discards the messages or files you have previously flagged for
deletion.
File Locking
Emacs used file locking to notice when two different users start
to edit one file at the same time. *Note Interlocking::.
File Name
A file name is a name that refers to a file. File names may be
relative or absolute; the meaning of a relative file name depends
on the current directory, but an absolute file name refers to the
same file regardless of which directory is current. On GNU and
Unix systems, an absolute file name starts with a slash (the root
directory) or with `~/' or `~USER/' (a home directory).
Some people use the term "pathname" for file names, but we do not;
we use the word "path" only in the term "search path" (q.v.).
File-Name Component
A file-name component names a file directly within a particular
directory. On GNU and Unix systems, a file name is a sequence of
file-name components, separated by slashes. For example, `foo/bar'
is a file name containing two components, `foo' and `bar'; it
refers to the file named `bar' in the directory named `foo' in the
current directory.
Fill Prefix
The fill prefix is a string that should be expected at the
beginning of each line when filling is done. It is not regarded
as part of the text to be filled. *Note Filling::.
Filling
Filling text means shifting text between consecutive lines so that
all the lines are approximately the same length. *Note Filling::.
Formatted Text
Formatted text is text that displays with formatting information
while you edit. Formatting information includes fonts, colors,
and specified margins. *Note Formatted Text::.
Frame
A frame is a rectangular cluster of Emacs windows. Emacs starts
out with one frame, but you can create more. You can subdivide
each frame into Emacs windows (q.v.). When you are using X
windows, all the frames can be visible at the same time. *Note
Frames::.
Function Key
A function key is a key on the keyboard that sends input but does
not correspond to any character. *Note Function Keys::.
Global
Global means `independent of the current environment; in effect
throughout Emacs'. It is the opposite of local (q.v.). Particular
examples of the use of `global' appear below.
Global Abbrev
A global definition of an abbrev (q.v.) is effective in all major
modes that do not have local (q.v.) definitions for the same
abbrev. *Note Abbrevs::.
Global Keymap
The global keymap (q.v.) contains key bindings that are in effect
except when overridden by local key bindings in a major mode's
local keymap (q.v.). *Note Keymaps::.
Global Mark Ring
The global mark ring records the series of buffers you have
recently set a mark in. In many cases you can use this to
backtrack through buffers you have been editing in, or in which
you have found tags. *Note Global Mark Ring::.
Global Substitution
Global substitution means replacing each occurrence of one string
by another string through a large amount of text. *Note Replace::.
Global Variable
The global value of a variable (q.v.) takes effect in all buffers
that do not have their own local (q.v.) values for the variable.
*Note Variables::.
Graphic Character
Graphic characters are those assigned pictorial images rather than
just names. All the non-Meta (q.v.) characters except for the
Control (q.v.) characters are graphic characters. These include
letters, digits, punctuation, and spaces; they do not include
<RET> or <ESC>. In Emacs, typing a graphic character inserts that
character (in ordinary editing modes). *Note Basic Editing: Basic.
Highlighting
Highlighting text means displaying it with a different foreground
and/or background color to make it stand out from the rest of the
text in the buffer.
Hardcopy
Hardcopy means printed output. Emacs has commands for making
printed listings of text in Emacs buffers. *Note Hardcopy::.
<HELP>
<HELP> is the Emacs name for `C-h' or <F1>. You can type <HELP>
at any time to ask what options you have, or to ask what any
command does. *Note Help::.
Hyper
Hyper is the name of a modifier bit which a keyboard input
character may have. To make a character Hyper, type it while
holding down the <HYPER> key. Such characters are given names
that start with `Hyper-' (usually written `H-' for short). *Note
Hyper: User Input.
Inbox
An inbox is a file in which mail is delivered by the operating
system. Rmail transfers mail from inboxes to Rmail files (q.v.)
in which the mail is then stored permanently or until explicitly
deleted. *Note Rmail Inbox::.
Indentation
Indentation means blank space at the beginning of a line. Most
programming languages have conventions for using indentation to
illuminate the structure of the program, and Emacs has special
commands to adjust indentation. *Note Indentation::.
Indirect Buffer
An indirect buffer is a buffer that shares the text of another
buffer, called its base buffer. *Note Indirect Buffers::.
Input Event
An input event represents, within Emacs, one action taken by the
user on the terminal. Input events include typing characters,
typing function keys, pressing or releasing mouse buttons, and
switching between Emacs frames. *Note User Input::.
Input Method
An input method is a system for entering non-ASCII text characters
by typing sequences of ASCII characters (q.v.). *Note Input
Methods::.
Insertion
Insertion means copying text into the buffer, either from the
keyboard or from some other place in Emacs.
Interlocking
Interlocking is a feature for warning when you start to alter a
file that someone else is already editing. *Note Simultaneous
Editing: Interlocking.
Justification
Justification means adding extra spaces to lines of text to make
them come exactly to a specified width. *Note Justification:
Filling.
Keyboard Macro
Keyboard macros are a way of defining new Emacs commands from
sequences of existing ones, with no need to write a Lisp program.
*Note Keyboard Macros::.
Key Sequence
A key sequence (key, for short) is a sequence of input events
(q.v.) that are meaningful as a single unit. If the key sequence
is enough to specify one action, it is a complete key (q.v.); if
it is not enough, it is a prefix key (q.v.). *Note Keys::.
Keymap
The keymap is the data structure that records the bindings (q.v.)
of key sequences to the commands that they run. For example, the
global keymap binds the character `C-n' to the command function
`next-line'. *Note Keymaps::.
Keyboard Translation Table
The keyboard translation table is an array that translates the
character codes that come from the terminal into the character
codes that make up key sequences. *Note Keyboard Translations::.
Kill Ring
The kill ring is where all text you have killed recently is saved.
You can reinsert any of the killed text still in the ring; this is
called yanking (q.v.). *Note Yanking::.
Killing
Killing means erasing text and saving it on the kill ring so it
can be yanked (q.v.) later. Some other systems call this
"cutting." Most Emacs commands to erase text do killing, as
opposed to deletion (q.v.). *Note Killing::.
Killing Jobs
Killing a job (such as, an invocation of Emacs) means making it
cease to exist. Any data within it, if not saved in a file, is
lost. *Note Exiting::.
Language Environment
Your choice of language environment specifies defaults for the
input method (q.v.) and coding system (q.v.). *Note Language
Environments::. These defaults are relevant if you edit non-ASCII
text (*note International::.).
List
A list is, approximately, a text string beginning with an open
parenthesis and ending with the matching close parenthesis. In C
mode and other non-Lisp modes, groupings surrounded by other kinds
of matched delimiters appropriate to the language, such as braces,
are also considered lists. Emacs has special commands for many
operations on lists. *Note Lists::.
Local
Local means `in effect only in a particular context'; the relevant
kind of context is a particular function execution, a particular
buffer, or a particular major mode. It is the opposite of `global'
(q.v.). Specific uses of `local' in Emacs terminology appear
below.
Local Abbrev
A local abbrev definition is effective only if a particular major
mode is selected. In that major mode, it overrides any global
definition for the same abbrev. *Note Abbrevs::.
Local Keymap
A local keymap is used in a particular major mode; the key bindings
(q.v.) in the current local keymap override global bindings of the
same key sequences. *Note Keymaps::.
Local Variable
A local value of a variable (q.v.) applies to only one buffer.
*Note Locals::.
`M-'
`M-' in the name of a character is an abbreviation for <META>, one
of the modifier keys that can accompany any character. *Note User
Input::.
`M-C-'
`M-C-' in the name of a character is an abbreviation for
Control-Meta; it means the same thing as `C-M-'. If your terminal
lacks a real <META> key, you type a Control-Meta character by
typing <ESC> and then typing the corresponding Control character.
*Note C-M-: User Input.
`M-x'
`M-x' is the key sequence which is used to call an Emacs command by
name. This is how you run commands that are not bound to key
sequences. *Note M-x::.
Mail
Mail means messages sent from one user to another through the
computer system, to be read at the recipient's convenience. Emacs
has commands for composing and sending mail, and for reading and
editing the mail you have received. *Note Sending Mail::. *Note
Rmail::, for how to read mail.
Mail Composition Method
A mail composition method is a program runnable within Emacs for
editing and sending a mail message. Emacs lets you select from
several alternative mail composition methods. *Note Mail
Methods::.
Major Mode
The Emacs major modes are a mutually exclusive set of options,
each of which configures Emacs for editing a certain sort of text.
Ideally, each programming language has its own major mode. *Note
Major Modes::.
Mark
The mark points to a position in the text. It specifies one end
of the region (q.v.), point being the other end. Many commands
operate on all the text from point to the mark. Each buffer has
its own mark. *Note Mark::.
Mark Ring
The mark ring is used to hold several recent previous locations of
the mark, just in case you want to move back to them. Each buffer
has its own mark ring; in addition, there is a single global mark
ring (q.v.). *Note Mark Ring::.
Menu Bar
The menu bar is the line at the top of an Emacs frame. It contains
words you can click on with the mouse to bring up menus. The menu
bar feature is supported only with X. *Note Menu Bars::.
Message
See `mail'.
Meta
Meta is the name of a modifier bit which a command character may
have. It is present in a character if the character is typed with
the <META> key held down. Such characters are given names that
start with `Meta-' (usually written `M-' for short). For example,
`M-<' is typed by holding down <META> and at the same time typing
`<' (which itself is done, on most terminals, by holding down
<SHIFT> and typing `,'). *Note Meta: User Input.
Meta Character
A Meta character is one whose character code includes the Meta bit.
Minibuffer
The minibuffer is the window that appears when necessary inside the
echo area (q.v.), used for reading arguments to commands. *Note
Minibuffer::.
Minibuffer History
The minibuffer history records the text you have specified in the
past for minibuffer arguments, so you can conveniently use the
same text again. *Note Minibuffer History::.
Minor Mode
A minor mode is an optional feature of Emacs which can be switched
on or off independently of all other features. Each minor mode
has a command to turn it on or off. *Note Minor Modes::.
Minor Mode Keymap
A keymap that belongs to a minor mode and is active when that mode
is enabled. Minor mode keymaps take precedence over the buffer's
local keymap, just as the local keymap takes precedence over the
global keymap. *Note Keymaps::.
Mode Line
The mode line is the line at the bottom of each window (q.v.),
giving status information on the buffer displayed in that window.
*Note Mode Line::.
Modified Buffer
A buffer (q.v.) is modified if its text has been changed since the
last time the buffer was saved (or since when it was created, if it
has never been saved). *Note Saving::.
Moving Text
Moving text means erasing it from one place and inserting it in
another. The usual way to move text by killing (q.v.) and then
yanking (q.v.). *Note Killing::.
MULE
MULE refers to the Emacs features for editing non-ASCII text using
multibyte characters (q.v.). *Note International::.
Multibyte Character
A multibyte character is a character that takes up several buffer
positions. Emacs uses multibyte characters to represent non-ASCII
text, since the number of non-ASCII characters is much more than
256. *Note International Intro::.
Named Mark
A named mark is a register (q.v.) in its role of recording a
location in text so that you can move point to that location.
*Note Registers::.
Narrowing
Narrowing means creating a restriction (q.v.) that limits editing
in the current buffer to only a part of the text in the buffer.
Text outside that part is inaccessible to the user until the
boundaries are widened again, but it is still there, and saving
the file saves it all. *Note Narrowing::.
Newline
Control-J characters in the buffer terminate lines of text and are
therefore also called newlines. *Note Newline: Text Characters.
Numeric Argument
A numeric argument is a number, specified before a command, to
change the effect of the command. Often the numeric argument
serves as a repeat count. *Note Arguments::.
Overwrite Mode
Overwrite mode is a minor mode. When it is enabled, ordinary text
characters replace the existing text after point rather than
pushing it to the right. *Note Minor Modes::.
Page
A page is a unit of text, delimited by formfeed characters (ASCII
control-L, code 014) coming at the beginning of a line. Some Emacs
commands are provided for moving over and operating on pages.
*Note Pages::.
Paragraph
Paragraphs are the medium-size unit of English text. There are
special Emacs commands for moving over and operating on paragraphs.
*Note Paragraphs::.
Parsing
We say that certain Emacs commands parse words or expressions in
the text being edited. Really, all they know how to do is find
the other end of a word or expression. *Note Syntax::.
Point
Point is the place in the buffer at which insertion and deletion
occur. Point is considered to be between two characters, not at
one character. The terminal's cursor (q.v.) indicates the
location of point. *Note Point: Basic.
Prefix Argument
See `numeric argument'.
Prefix Key
A prefix key is a key sequence (q.v.) whose sole function is to
introduce a set of longer key sequences. `C-x' is an example of
prefix key; any two-character sequence starting with `C-x' is
therefore a legitimate key sequence. *Note Keys::.
Primary Rmail File
Your primary Rmail file is the file named `RMAIL' in your home
directory. That's where Rmail stores your incoming mail, unless
you specify a different file name. *Note Rmail::.
Primary Selection
The primary selection is one particular X selection (q.v.); it is
the selection that most X applications use for transferring text
to and from other applications.
The Emacs kill commands set the primary selection and the yank
command uses the primary selection when appropriate. *Note
Killing::.
Prompt
A prompt is text printed to ask the user for input. Displaying a
prompt is called prompting. Emacs prompts always appear in the
echo area (q.v.). One kind of prompting happens when the
minibuffer is used to read an argument (*note Minibuffer::.); the
echoing which happens when you pause in the middle of typing a
multi-character key sequence is also a kind of prompting (*note
Echo Area::.).
Quitting
Quitting means canceling a partially typed command or a running
command, using `C-g' (or `C-<BREAK>' on MS-DOS). *Note Quitting::.
Quoting
Quoting means depriving a character of its usual special
significance. The most common kind of quoting in Emacs is with
`C-q'. What constitutes special significance depends on the
context and on convention. For example, an "ordinary" character
as an Emacs command inserts itself; so in this context, a special
character is any character that does not normally insert itself
(such as <DEL>, for example), and quoting it makes it insert
itself as if it were not special. Not all contexts allow quoting.
*Note Quoting: Basic.
Quoting File Names
Quoting a file name turns off the special significance of
constructs such as `$', `~' and `:'. *Note Quoted File Names::.
Read-Only Buffer
A read-only buffer is one whose text you are not allowed to change.
Normally Emacs makes buffers read-only when they contain text which
has a special significance to Emacs; for example, Dired buffers.
Visiting a file that is write-protected also makes a read-only
buffer. *Note Buffers::.
Rectangle
A rectangle consists of the text in a given range of columns on a
given range of lines. Normally you specify a rectangle by putting
point at one corner and putting the mark at the opposite corner.
*Note Rectangles::.
Recursive Editing Level
A recursive editing level is a state in which part of the
execution of a command involves asking the user to edit some text.
This text may or may not be the same as the text to which the
command was applied. The mode line indicates recursive editing
levels with square brackets (`[' and `]'). *Note Recursive Edit::.
Redisplay
Redisplay is the process of correcting the image on the screen to
correspond to changes that have been made in the text being edited.
*Note Redisplay: Screen.
Regexp
See `regular expression'.
Region
The region is the text between point (q.v.) and the mark (q.v.).
Many commands operate on the text of the region. *Note Region:
Mark.
Registers
Registers are named slots in which text or buffer positions or
rectangles can be saved for later use. *Note Registers::.
Regular Expression
A regular expression is a pattern that can match various text
strings; for example, `l[0-9]+' matches `l' followed by one or more
digits. *Note Regexps::.
Repeat Count
See `numeric argument'.
Replacement
See `global substitution'.
Restriction
A buffer's restriction is the amount of text, at the beginning or
the end of the buffer, that is temporarily inaccessible. Giving a
buffer a nonzero amount of restriction is called narrowing (q.v.).
*Note Narrowing::.
<RET>
<RET> is a character that in Emacs runs the command to insert a
newline into the text. It is also used to terminate most arguments
read in the minibuffer (q.v.). *Note Return: User Input.
Rmail File
An Rmail file is a file containing text in a special format used by
Rmail for storing mail. *Note Rmail::.
Saving
Saving a buffer means copying its text into the file that was
visited (q.v.) in that buffer. This is the way text in files
actually gets changed by your Emacs editing. *Note Saving::.
Scroll Bar
A scroll bar is a tall thin hollow box that appears at the side of
a window. You can use mouse commands in the scroll bar to scroll
the window. The scroll bar feature is supported only with X.
*Note Scroll Bars::.
Scrolling
Scrolling means shifting the text in the Emacs window so as to see
a different part of the buffer. *Note Scrolling: Display.
Searching
Searching means moving point to the next occurrence of a specified
string or the next match for a specified regular expression.
*Note Search::.
Search Path
A search path is a list of directory names, to be used for
searching for files for certain purposes. For example, the
variable `load-path' holds a search path for finding Lisp library
files. *Note Lisp Libraries::.
Secondary Selection
The secondary selection is one particular X selection; some X
applications can use it for transferring text to and from other
applications. Emacs has special mouse commands for transferring
text using the secondary selection. *Note Secondary Selection::.
Selecting
Selecting a buffer means making it the current (q.v.) buffer.
*Note Selecting: Buffers.
Selection
The X window system allows an application program to specify named
selections whose values are text. A program can also read the
selections that other programs have set up. This is the principal
way of transferring text between window applications. Emacs has
commands to work with the primary (q.v.) selection and the
secondary (q.v.) selection.
Self-Documentation
Self-documentation is the feature of Emacs which can tell you what
any command does, or give you a list of all commands related to a
topic you specify. You ask for self-documentation with the help
character, `C-h'. *Note Help::.
Self-Inserting Character
A character is self-inserting if typing that character inserts that
character in the buffer. Ordinary printing and whitespace
characters are self-inserting in Emacs, except in certain special
major modes.
Sentences
Emacs has commands for moving by or killing by sentences. *Note
Sentences::.
Sexp
A sexp (short for `s-expression') is the basic syntactic unit of
Lisp in its textual form: either a list, or Lisp atom. Many Emacs
commands operate on sexps. The term `sexp' is generalized to
languages other than Lisp, to mean a syntactically recognizable
expression. *Note Sexps: Lists.
Simultaneous Editing
Simultaneous editing means two users modifying the same file at
once. Simultaneous editing if not detected can cause one user to
lose his work. Emacs detects all cases of simultaneous editing
and warns one of the users to investigate. *Note Simultaneous
Editing: Interlocking.
String
A string is a kind of Lisp data object which contains a sequence of
characters. Many Emacs variables are intended to have strings as
values. The Lisp syntax for a string consists of the characters
in the string with a `"' before and another `"' after. A `"' that
is part of the string must be written as `\"' and a `\' that is
part of the string must be written as `\\'. All other characters,
including newline, can be included just by writing them inside the
string; however, backslash sequences as in C, such as `\n' for
newline or `\241' using an octal character code, are allowed as
well.
String Substitution
See `global substitution'.
Syntax Table
The syntax table tells Emacs which characters are part of a word,
which characters balance each other like parentheses, etc. *Note
Syntax::.
Super
Super is the name of a modifier bit which a keyboard input
character may have. To make a character Super, type it while
holding down the <SUPER> key. Such characters are given names
that start with `Super-' (usually written `s-' for short). *Note
Super: User Input.
Tags Table
A tags table is a file that serves as an index to the function
definitions in one or more other files. *Note Tags::.
Termscript File
A termscript file contains a record of all characters sent by
Emacs to the terminal. It is used for tracking down bugs in Emacs
redisplay. Emacs does not make a termscript file unless you tell
it to. *Note Bugs::.
Text
Two meanings (*note Text::.):
* Data consisting of a sequence of characters, as opposed to
binary numbers, images, graphics commands, executable
programs, and the like. The contents of an Emacs buffer are
always text in this sense.
* Data consisting of written human language, as opposed to
programs, or following the stylistic conventions of human
language.
Top Level
Top level is the normal state of Emacs, in which you are editing
the text of the file you have visited. You are at top level
whenever you are not in a recursive editing level (q.v.) or the
minibuffer (q.v.), and not in the middle of a command. You can
get back to top level by aborting (q.v.) and quitting (q.v.).
*Note Quitting::.
Transposition
Transposing two units of text means putting each one into the place
formerly occupied by the other. There are Emacs commands to
transpose two adjacent characters, words, sexps (q.v.) or lines
(*note Transpose::.).
Truncation
Truncating text lines in the display means leaving out any text on
a line that does not fit within the right margin of the window
displaying it. See also `continuation line'. *Note Truncation:
Basic.
Undoing
Undoing means making your previous editing go in reverse, bringing
back the text that existed earlier in the editing session. *Note
Undo::.
User Option
A user option is a variable (q.v.) that exists so that you can
customize Emacs by setting it to a new value. *Note Variables::.
Variable
A variable is an object in Lisp that can store an arbitrary value.
Emacs uses some variables for internal purposes, and has others
(known as `user options' (q.v.)) just so that you can set their
values to control the behavior of Emacs. The variables used in
Emacs that you are likely to be interested in are listed in the
Variables Index in this manual. *Note Variables::, for
information on variables.
Version Control
Version control systems keep track of multiple versions of a
source file. They provide a more powerful alternative to keeping
backup files (q.v.). *Note Version Control::.
Visiting
Visiting a file means loading its contents into a buffer (q.v.)
where they can be edited. *Note Visiting::.
Whitespace
Whitespace is any run of consecutive formatting characters (space,
tab, newline, and backspace).
Widening
Widening is removing any restriction (q.v.) on the current buffer;
it is the opposite of narrowing (q.v.). *Note Narrowing::.
Window
Emacs divides a frame (q.v.) into one or more windows, each of
which can display the contents of one buffer (q.v.) at any time.
*Note Screen::, for basic information on how Emacs uses the screen.
*Note Windows::, for commands to control the use of windows.
Word Abbrev
Synonymous with `abbrev'.
Word Search
Word search is searching for a sequence of words, considering the
punctuation between them as insignificant. *Note Word Search::.
WYSIWYG
WYSIWYG stands for `What you see is what you get.' Emacs generally
provides WYSIWYG editing for files of characters; in Enriched mode
(*note Formatted Text::.), it provides WYSIWYG editing for files
that include text formatting information.
Yanking
Yanking means reinserting text previously killed. It can be used
to undo a mistaken kill, or for copying or moving text. Some other
systems call this "pasting." *Note Yanking::.
Acknowledgments
***************
Many people have contributed code included in the Free Software
Foundation's distribution of GNU Emacs. To show our appreciation for
their public spirit, we list here those who have written substantial
portions.
* Per Abrahamsen wrote the customization buffer facilities, as well
as `double.el' for typing accented characters not normally
available from the keyboard, `xt-mouse.el' which handles mouse
commands through Xterm, and `cpp.el' which hides or highlights
parts of C programs according to preprocessor conditionals.
* Jay K. Adams wrote `jka-compr.el', providing automatic
decompression and recompression for compressed files.
* Joe Arceneaux wrote the original text property implementation, and
implemented support for X11.
* Boaz Ben-Zvi wrote `profile.el', to time Emacs Lisp functions.
* Jim Blandy wrote Emacs 19's input system, brought its
configuration and build process up to the GNU coding standards,
and contributed to the frame support and multi-face support.
* Terrence M. Brannon wrote `landmark.el', a neural-network robot
that learns landmarks.
* Frank Bresz wrote `diff.el', a program to display `diff' output.
* Peter Breton implemented `dirtrack' which does better tracking of
directory changes in shell buffers, `filecache.el' which records
which directories your files are in, `locate.el' which interfaces
to the `locate' command, `net-utils.el', and the "generic mode"
feature.
* Kevin Broadey wrote `foldout.el', providing folding extensions to
Emacs's outline modes.
* Vincent Broman wrote `ada.el', a mode for editing Ada code (since
replaced by `ada-mode.el').
* David M. Brown wrote `array.el', for editing arrays and other
tabular data.
* Bill Carpenter provided `feedmail.el'.
* Hans Chalupsky wrote `advice.el', an overloading mechanism for
Emacs Lisp functions, and `trace.el', a tracing facility for Emacs
Lisp.
* Bob Chassell wrote `texnfo-upd.el' and `makeinfo.el', modes and
utilities for working with Texinfo files.
* James Clark wrote `sgml-mode.el', a mode for editing SGML
documents, and contributed to Emacs's dumping procedures.
* Mike Clarkson wrote `edt.el', an emulation of DEC's EDT editor.
* Glynn Clements provided `gamegrid.el' and a couple of games that
use it, Snake and Tetris.
* Andrew Csillag wrote M4 mode (`m4-mode.el').
* Doug Cutting and Jamie Zawinski wrote `disass.el', a disassembler
for compiled Emacs Lisp code.
* Michael DeCorte wrote `emacs.csh', a C-shell script that starts a
new Emacs job, or restarts a paused Emacs if one exists.
* Gary Delp wrote `mailpost.el', an interface between RMAIL and the
`/usr/uci/post' mailer.
* Matthieu Devin wrote `delsel.el', a package to make newly-typed
text replace the current selection.
* Eric Ding contributed `goto-addr.el',
* Carsten Dominik wrote `reftex.el', a package for setting up labels
and cross-references for LaTeX.
* Scott Draves wrote `tq.el', help functions for maintaining
transaction queues between Emacs and its subprocesses.
* Viktor Dukhovni wrote support for dumping under SunOS version 4.
* John Eaton co-wrote Octave mode (`octave.el' and related files).
* Rolf Ebert co-wrote Ada mode (`ada-mode.el').
* Stephen Eglen implemented `mspools.el', for use with Procmail,
which tells you which mail folders have mail waiting in them, and
`iswitchb.el', a feature for incremental reading and completion of
buffer names.
* Torbj"orn Einarsson contributed F90 mode (`f90.el').
* Tsugutomo Enami co-wrote the support for international character
sets.
* Hans Henrik Eriksen wrote `simula.el', a mode for editing SIMULA 87
code.
* Michael Ernst wrote `reposition.el', a command for recentering a
function's source code and preceding comment on the screen.
* Ata Etemadi wrote `cdl.el', functions for working with Common Data
Language source code.
* Frederick Farnback implemented `morse.el', which converts text to
morse code.
* Fred Fish wrote the support for dumping COFF executable files.
* Karl Fogel wrote:
* `bookmark.el', for creating named placeholders, saving them
and jumping to them later,
* `mail-hist.el', a history mechanism for outgoing mail
messages, and
* `saveplace.el', for preserving point's location in files
between editing sessions.
* Gary Foster wrote the emulation for CRiSP: `crisp.el' and
`scroll-lock.el'.
* Noah Friedman wrote `rlogin.el', an interface to Rlogin, and
`type-break.el', which reminds you to take periodic breaks from
typing. With Roland McGrath, he wrote `rsz-mini.el', a minor mode
to automatically resize the minibuffer to fit the text it contains.
* Keith Gabryelski wrote `hexl.el', a mode for editing binary files.
* Kevin Gallagher rewrote and enhanced the EDT emulation, and wrote
`flow-ctrl.el', a package for coping with unsuppressible XON/XOFF
flow control.
* Kevin Gallo added multiple-frame support for Windows NT.
* Howard Gayle wrote:
* the C and lisp code for display tables and case tables,
* `rot13.el', a command to display the plaintext form of a
buffer encoded with the Caesar cipher,
* much of the support for the ISO-8859 European character set
(which includes `iso-ascii.el', `iso-insert.el',
`iso-swed.el', `iso-syntax.el', `iso-transl.el', and
`swedish.el'), and
* `vt100-led.el', a package for controlling the LED's on
VT100-compatible terminals.
* Stephen Gildea made the Emacs quick reference card.
* David Gillespie wrote:
* Emacs 19's Common Lisp compatibility packages, replacing the
old package by Cesar Augusto Quiroz Gonzalez,
* `complete.el', a partial completion mechanism, and
* `edmacro.el', a package for editing keyboard macros.
* Bob Glickstein contributed the `sregex.el' feature.
* Boris Goldowsky wrote `avoid.el', a package to keep the mouse
cursor out of the way of the text cursor; `shadowfile.el', a
package for keeping identical copies of files in more than one
place; `enriched.el', a package for saving text properties in
files; and `facemenu.el', a package for specifying faces.
* Michelangelo Grigni wrote `ffap.el' which visits a file, taking
the file name from the buffer.
* Odd Gripenstam wrote `dcl-mode.el'.
* Michael Gschwind wrote `iso-cvt.el', a package to convert between
the ISO 8859-1 character set and the notations for non-`ASCII'
characters used by TeX and net tradition.
* Henry Guillaume wrote `find-file.el', a package to visit files
related to the currently visited file.
* Doug Gwyn wrote the portable `alloca' implementation.
* Ken'ichi Handa implemented most of the support for international
character sets.
* Chris Hanson wrote `netuname.el', a package to use HP-UX's Remote
File Access facility from Emacs.
* K. Shane Hartman wrote:
* `chistory.el' and `echistory.el', packages for browsing
command history lists,
* `electric.el' and `helper.el', providing an alternative
command loop and appropriate help facilities,
* `emacsbug.el', a package for reporting Emacs bugs,
* `picture.el', a mode for editing ASCII pictures, and
* `view.el', a package for perusing files and buffers without
editing them.
* John Heidemann wrote `mouse-copy.el' and `mouse-drag.el', which
provide alternative mouse-based editing and scrolling features.
* Markus Heritsch co-wrote Ada mode (`ada-mode.el').
* Karl Heuer wrote the original blessmail script, implemented the
`intangible' text property, and rearranged the structure of the
`Lisp_Object' type to allow for more data bits.
* Manabu Higashida ported Emacs to the MS-DOS operating system.
* Anders Holst wrote `hippie-exp.el', a versatile completion and
expansion package.
* Kurt Hornik co-wrote Octave mode (`octave.el' and related files).
* Tom Houlder wrote `mantemp.el', which generates manual C++ template
instantiations.
* Lars Ingebrigtsen did a major redesign of the GNUS newsreader.
* Andrew Innes contributed extensively to the Windows NT support.
* Kyle Jones wrote `life.el', a package to play Conway's "life" game,
and `mldrag.el', a package which allows the user to resize windows
by dragging mode lines and vertical window separators with the
mouse.
* Tomoji Kagatani implemented `smtpmail.el', used for sending out
mail with SMTP.
* David Kaufman wrote `yow.c', an essential utility program for the
hopelessly pinheaded.
* Henry Kautz wrote `bib-mode.el', a mode for maintaining
bibliography databases compatible with `refer' (the `troff'
version) and `lookbib', and `refbib.el', a package to convert
those databases to the format used by the LaTeX text formatting
package.
* Howard Kaye wrote `sort.el', commands to sort text in Emacs
buffers.
* Michael Kifer wrote `ediff.el', an interactive interface to the
`diff' and `patch' programs, and Viper, the newest emulation for
VI.
* Richard King wrote the first version of `userlock.el' and
`filelock.c', which provide simple support for multiple users
editing the same file.
* Larry K. Kolodney wrote `cvtmail.c', a program to convert the mail
directories used by Gosling Emacs into RMAIL format.
* Robert Krawitz wrote the original `xmenu.c', part of Emacs's pop-up
menu support.
* Sebastian Kremer wrote Emacs 19's `dired-mode', with contributions
by Lawrence R. Dodd.
* Geoff Kuenning wrote Emacs 19's `ispell.el', based on work by Ken
Stevens and others.
* David K*agedal wrote `tempo.el', providing support for easy
insertion of boilerplate text and other common constructions.
* Daniel LaLiberte wrote:
* `edebug.el', a source-level debugger for Emacs Lisp,
* `cl-specs.el', specifications to help `edebug' debug code
written using David Gillespie's Common Lisp support,
* `cust-print.el', a customizable package for printing lisp
objects,
* `eval-reg.el', a re-implementation of `eval-region' in Emacs
Lisp, and
* `isearch.el', Emacs 19's incremental search minor mode.
* James R. Larus wrote `mh-e.el', an interface to the MH mail system.
* Frederic Lepied contributed `expand.el', which uses the abbrev
mechanism for inserting programming constructs.
* Lars Lindberg wrote `msb.el', which provides more flexible menus
for buffer selection, and rewrote `dabbrev.el'.
* Eric Ludlam wrote the Speedbar package and `checkdoc.el'.
* Neil M. Mager wrote `appt.el', functions to notify users of their
appointments. It finds appointments recorded in the diary files
generated by Edward M. Reingold's `calendar' package.
* Ken Manheimer wrote `allout.el', a mode for manipulating and
formatting outlines, and `icomplete.el', which provides incremental
completion feedback in the minibuffer.
* Bill Mann wrote `perl-mode.el', a mode for editing Perl code.
* Brian Marick and Daniel LaLiberte wrote `hideif.el', support for
hiding selected code within C `#ifdef' clauses.
* Simon Marshall wrote:
* `fast-lock.el', which caches the face data computed by Font
Lock mode,
* `lazy-lock.el', which delays fontification in Font Lock mode
until text is actually displayed, and
* `regexp-opt.el', which generates a regular expression from a
list of strings.
* Bengt Martensson, Mark Shapiro, Mike Newton, Aaron Larson, and
Stefan Schoef, wrote `bibtex.el', a mode for editing BibTeX
bibliography files.
* Charlie Martin wrote `autoinsert.el', which provides automatic
mode-sensitive insertion of text into new files.
* Thomas May wrote `blackbox.el', a version of the traditional
blackbox game.
* Roland McGrath wrote:
* `compile.el', a package for running compilations in a buffer,
and then visiting the locations reported in error messages,
* `etags.el', a package for jumping to function definitions and
searching or replacing in all the files mentioned in a `TAGS'
file,
* `find-dired.el', for using `dired' commands on output from the
`find' program, with Sebastian Kremer,
* `map-ynp.el', a general purpose boolean question-asker,
* `autoload.el', providing semi-automatic maintenance of
autoload files, and
* `upd-copyr.el', providing semi-automatic maintenance of
copyright notices in source code.
* David Megginson wrote `derived.el', which allows one to define new
major modes by inheriting key bindings and commands from existing
major modes.
* Wayne Mesard wrote `hscroll.el' which does horizontal scrolling
automatically.
* Richard Mlynarik wrote:
* `cl-indent.el', a package for indenting Common Lisp code,
* `ebuff-menu.el', an "electric" browser for buffer listings,
* `ehelp.el', bindings for browsing help screens,
* `rfc822.el', a parser for E-mail addresses in the RFC-822
format, used in mail messages and news articles,
* `terminal.el', a terminal emulator for Emacs subprocesses, and
* `yow.el', an essential utility (try `M-x yow').
* Keith Moore wrote `aixcc.lex', a pre-processor designed to help
Emacs parse the error messages produced by the AIX C compiler.
* Erik Naggum wrote the time-conversion functions, and has tested the
latest source code daily.
* Thomas Neumann and Eric Raymond wrote `makefile.el', a mode for
editing makefiles.
* Jurgen Nickelsen wrote `ws-mode.el', providing WordStar emulation.
* Jeff Norden wrote `kermit.el', a package to help the Kermit dialup
communications program run comfortably in an Emacs shell buffer.
* Andrew Norman wrote `ange-ftp.el', providing transparent FTP
support.
* Jeff Peck wrote:
* `emacstool.c', support for running Emacs under SunView/Sun
Windows,
* `sun-curs.el', cursor definitions for Sun Windows, and
* `sun-fns.el', providing mouse support for Sun Windows.
* Damon Anton Permezel wrote `hanoi.el', an animated demonstration of
the "Towers of Hanoi" puzzle.
* Jens Petersen wrote `find-func.el', which makes it easy to find
the source code for an Emacs Lisp function or variable.
* Daniel Pfeiffer wrote:
* `executable.el'
* `sh-script.el', a mode for editing shell scripts,
* `skeleton.el', implementing a concise language for writing
statement skeletons, and
* `two-column.el', a minor mode for simultaneous two-column
editing.
* Fred Pierresteguy and Paul Reilly made Emacs work with X Toolkit
widgets.
* Christian Plaunt wrote `soundex.el', an implementation of the
Soundex algorithm for comparing English words by their
pronunciation.
* Francesco A. Potorti wrote `cmacexp.el', providing a command which
runs the C preprocessor on a region of a file and displays the
results.
* Michael D. Prange and Steven A. Wood wrote `fortran.el', a mode for
editing FORTRAN code.
* Ashwin Ram wrote `refer.el', commands to look up references in
bibliography files by keyword.
* Eric S. Raymond wrote:
* `vc.el', an interface to the RCS and SCCS source code version
control systems, with Paul Eggert,
* `gud.el', a package for running source-level debuggers like
GDB and SDB in Emacs,
* `asm-mode.el', a mode for editing assembly language code,
* `cookie1.el', support for "fortune-cookie" programs like
`yow.el' and `spook.el',
* `finder.el', a package for finding Emacs Lisp packages by
keyword and topic,
* `lisp-mnt.el', functions for working with the special headers
used in Emacs Lisp library files, and
* code to set and make use of the `load-history' lisp variable,
which records the source file from which each lisp function
loaded into Emacs came.
* Edward M. Reingold wrote the extensive calendar and diary support
(try `M-x calendar'), with contributions from Stewart Clamen, Paul
Eggert, and Lara Rios. Andy Oram contributed to its documentation.
Reingold has also contributed to `tex-mode.el', a mode for editing
TeX files, as have William F. Schelter, Dick King, Stephen Gildea,
Michael Prange, and Jacob Gore.
* Rob Riepel contributed `tpu-edt.el' and its associated files,
providing an emulation of the VMS TPU text editor emulating the
VMS EDT editor, and `vt-control.el', providing some control
functions for the DEC VT line of terminals.
* Roland B. Roberts contributed much of the VMS support distributed
with Emacs 19, along with Joseph M. Kelsey, and `vms-pmail.el',
support for using Emacs within VMS MAIL.
* John Robinson wrote `bg-mouse.el', support for the mouse on the BBN
Bitgraph terminal.
* Danny Roozendaal implemented `handwrite.el', which converts text
into "handwriting."
* William Rosenblatt wrote `float.el', implementing a floating-point
numeric type using Lisp cons cells and integers.
* Guillermo J. Rozas wrote `scheme.el', a mode for editing Scheme
code, and `fakemail.c', an interface to the System V mailer.
* Ivar Rummelhoff provided `winner.el', which records recent window
configurations so you can move back to them.
* Wolfgang Rupprecht contributed Emacs 19's floating-point support
(including `float-sup.el' and `floatfns.c'), and `sup-mouse.el',
support for the Supdup mouse on lisp machines.
* James B. Salem and Brewster Kahle wrote `completion.el', providing
dynamic word completion.
* Masahiko Sato wrote `vip.el', an emulation of the VI editor.
* William Schelter wrote `telnet.el', support for `telnet' sessions
within Emacs.
* Ralph Schleicher contributed `battery.el', a package for displaying
laptop computer battery status, and `info-look.el', a package for
looking up Info documentation for symbols in the buffer.
* Gregor Schmid wrote `tcl.el', a mode for editing Tcl/Tk scripts.
* Michael Schmidt and Tom Perrine wrote `modula2.el', a mode for
editing Modula-2 code, based on work by Mick Jordan and Peter
Robinson.
* Ronald S. Schnell wrote `dunnet.el', a text adventure game.
* Philippe Schnoebelen wrote `gomoku.el', a Go Moku game played
against Emacs, and `mpuz.el', a multiplication puzzle.
* Randal Schwartz wrote `pp.el', a pretty-printer for lisp objects.
* Manuel Serrano contributed the Flyspell package that does spell
checking as you type.
* Stanislav Shalunov wrote `uce.el', for responding to unsolicited
commercial email.
* Richard Sharman contributed `hilit-chg.el', which uses colors to
inclidate recent editing changes.
* Olin Shivers wrote:
* `comint.el', a library for modes running interactive
command-line- oriented subprocesses,
* `cmuscheme.el', for running inferior Scheme processes,
* `inf-lisp.el', for running inferior Lisp process, and
* `shell.el', for running inferior shells.
* Sam Shteingold wrote `gulp.el'.
* Espen Skoglund wrote `pascal.el', a mode for editing Pascal code.
* Rick Sladkey wrote `backquote.el', a lisp macro for creating
mostly-constant data.
* Lynn Slater wrote `help-macro.el', a macro for writing interactive
help for key bindings.
* Chris Smith wrote `icon.el', a mode for editing Icon code.
* David Smith wrote `ielm.el', a mode for interacting with the Emacs
Lisp interpreter as a subprocess.
* Paul D. Smith wrote `snmp-mode.el'.
* William Sommerfeld wrote `scribe.el', a mode for editing Scribe
files, and `server.el', a package allowing programs to send files
to an extant Emacs job to be edited.
* Michael Staats wrote `pc-select.el', which rebinds keys for
selecting regions to follow many other systems.
* Ake Stenhoff and Lars Lindberg wrote `imenu.el', a framework for
browsing indices made from buffer contents.
* Peter Stephenson contributed `vcursor.el', which implements a
"virtual cursor" that you can move with the keyboard and use for
copying text.
* Sam Steingold wrote `midnight.el'.
* Jonathan Stigelman wrote `hilit19.el', a package providing
automatic highlighting in source code buffers, mail readers, and
other contexts.
* Steve Strassman did not write `spook.el', and even if he did, he
really didn't mean for you to use it in an anarchistic way.
* Jens T. Berger Thielemann wrote `word-help.el', which is part of
the basis for `info-look.el'.
* Spencer Thomas wrote the original `dabbrev.el', providing a command
which completes the partial word before point, based on other
nearby words for which it is a prefix. He also wrote the original
dumping support.
* Jim Thompson wrote `ps-print.el', which converts Emacs text to
Postscript.
* Masanobu Umeda wrote:
* GNUS, a featureful reader for Usenet news,
* `prolog.el', a mode for editing Prolog code,
* `rmailsort.el', a package for sorting messages in RMAIL
folders,
* `metamail.el', an interface to the Metamail program,
* `tcp.el', emulation of the `open-network-stream' function for
some Emacs configurations which lack it, and
* `timezone.el', providing functions for dealing with time
zones.
* Neil W. Van Dyke wrote `webjump.el', a "hot links" package.
* Ulrik Vieth implemented `meta-mode.el', for editing MetaFont code.
* Geoffrey Voelker wrote the Windows NT support.
* Johan Vromans wrote `forms.el' and its associated files, defining a
mode for filling in forms, and `iso-acc.el', a minor mode providing
electric accent keys for text using the ISO-8859 character set.
* Barry Warsaw wrote:
* `assoc.el', a set of utility functions for working with
association lists,
* `cc-mode.el', a major mode for editing C and C++ code, based
on earlier work by Dave Detlefs, Stewart Clamen, and Richard
Stallman,
* `elp.el', a new profiler for Emacs Lisp programs.
* `man.el', a mode for reading UNIX manual pages,
* `regi.el', providing an AWK-like control structure for use in
lisp programs, and
* `reporter.el', providing customizable bug reporting for lisp
packages.
* `supercite.el', a minor mode for quoting sections of mail
messages and news articles,
* Morten Welinder wrote:
* `desktop.el', facilities for saving some of Emacs's state
between sessions,
* `s-region.el', commands for setting the region using the
shift key and motion commands, and
* `dos-fns.el', functions for use under MS-DOS.
He also helped port Emacs to MS-DOS.
* Joseph Brian Wells wrote:
* `apropos.el', a command to find commands, functions, and
variables whose names contain matches for a regular
expression,
* `resume.el', support for processing command-line arguments
after resuming a suspended Emacs job, and
* `mail-extr.el', a package for extracting names and addresses
from mail headers, with contributions from Jamie Zawinski.
* Rodney Whitby and Reto Zimmermann wrote `vhdl-mode.el'.
* Ed Wilkinson wrote `b2m.c', a program to convert mail files from
RMAIL format to Unix `mbox' format.
* Mike Williams wrote `mouse-sel.el', providing enhanced mouse
selection, and `thingatpt.el', a library of functions for finding
the "thing" (word, line, s-expression) containing point.
* Dale R. Worley wrote `emerge.el', a package for interactively
merging two versions of a file.
* Tom Wurgler wrote `emacs-lock.el', which makes it harder to exit
with valuable buffers unsaved.
* Eli Zaretskii made many standard Emacs features work on MS-DOS.
* Jamie Zawinski wrote:
* Emacs 19's optimizing byte compiler, with Hallvard Furuseth,
* much of the support for faces and X selections,
* `mailabbrev.el', a package providing automatic expansion of
mail aliases, and
* `tar-mode.el', providing simple viewing and editing commands
for tar files.
* Ian T. Zimmerman wrote `gametree.el'.
* Neal Ziring and Felix S. T. Wu wrote `vi.el', an emulation of the
VI text editor.
Others too numerous to mention have reported and fixed bugs, and
added features to many parts of Emacs. We thank them for their
generosity as well.
This list intended to mention every contributor of a major package or
feature we currently distribute; if you know of someone we have omitted,
please report that as a manual bug.
Key (Character) Index
*********************
* Menu:
* ! (Dired): Shell Commands in Dired.
* " (TeX mode): TeX Editing.
* # (Dired): Flagging Many Files.
* $ (Dired): Hiding Subdirectories.
* % C (Dired): Transforming File Names.
* % d (Dired): Flagging Many Files.
* % H (Dired): Transforming File Names.
* % l (Dired): Transforming File Names.
* % m (Dired): Marks vs Flags.
* % R (Dired): Transforming File Names.
* % S (Dired): Transforming File Names.
* % u (Dired): Transforming File Names.
* & (Dired): Flagging Many Files.
* * ! (Dired): Marks vs Flags.
* * % (Dired): Marks vs Flags.
* * * (Dired): Marks vs Flags.
* * / (Dired): Marks vs Flags.
* * ? (Dired): Marks vs Flags.
* * @ (Dired): Marks vs Flags.
* * c (Dired): Marks vs Flags.
* * C-n (Dired): Marks vs Flags.
* * C-p (Dired): Marks vs Flags.
* * DEL (Dired): Marks vs Flags.
* * m (Dired): Marks vs Flags.
* * s (Dired): Marks vs Flags.
* * t (Dired): Marks vs Flags.
* * u (Dired): Marks vs Flags.
* + (Dired): Operating on Files.
* . (Calendar mode): Specified Dates.
* . (Dired): Flagging Many Files.
* . (Rmail): Rmail Scrolling.
* < (Dired): Subdirectory Motion.
* < (Rmail): Rmail Motion.
* <TAB> (Help mode): Help Mode.
* = (Dired): Comparison in Dired.
* > (Dired): Subdirectory Motion.
* > (Rmail): Rmail Motion.
* a (Calendar mode): Holidays.
* A (Dired): Operating on Files.
* a (Rmail): Rmail Labels.
* B (Dired): Operating on Files.
* b (Rmail): Rmail Basics.
* BS (MS-DOS): MS-DOS Input.
* C (Dired): Operating on Files.
* c (Rmail): Rmail Reply.
* C-@: Setting Mark.
* C-\: Select Input Method.
* C-]: Quitting.
* C-_: Undo.
* C-_ (Dired): Marks vs Flags.
* C-a: Moving Point.
* C-a (Calendar mode): Move to Beginning or End.
* C-b: Moving Point.
* C-b (Calendar mode): Calendar Unit Motion.
* C-BREAK (MS-DOS): MS-DOS Input.
* C-c ' (Picture mode): Insert in Picture.
* C-c . (Picture mode): Insert in Picture.
* C-c / (Picture mode): Insert in Picture.
* C-c : (C mode): Electric C.
* C-c ; (Fortran mode): Fortran Comments.
* C-c < (GUD): Commands of GUD.
* C-c < (Picture mode): Insert in Picture.
* C-c > (GUD): Commands of GUD.
* C-c > (Picture mode): Insert in Picture.
* C-c @ (Outline minor mode): Outline Mode.
* C-c \ (Picture mode): Insert in Picture.
* C-c ^ (Picture mode): Insert in Picture.
* C-c ` (Picture mode): Insert in Picture.
* C-c C-\ (C mode): Other C Commands.
* C-c C-\ (Shell mode): Shell Mode.
* C-c C-a (C mode): Electric C.
* C-c C-a (Mail mode): Mail Aliases.
* C-c C-a (Outline mode): Outline Visibility.
* C-c C-a (Shell mode): Shell Mode.
* C-c C-b (Outline mode): Outline Motion.
* C-c C-b (Picture mode): Insert in Picture.
* C-c C-b (Shell mode): Shell Mode.
* C-c C-b (TeX mode): TeX Print.
* C-c C-c (Edit Abbrevs): Editing Abbrevs.
* C-c C-c (Edit Tab Stops): Tab Stops.
* C-c C-c (Mail mode): Mail Sending.
* C-c C-c (Outline mode): Outline Visibility.
* C-c C-c (Shell mode): Shell Mode.
* C-c C-d (C mode): Hungry Delete.
* C-c C-d (GUD): Commands of GUD.
* C-c C-d (Outline mode): Outline Visibility.
* C-c C-d (Picture mode): Basic Picture.
* C-c C-e (C mode): Other C Commands.
* C-c C-e (LaTeX mode): LaTeX Editing.
* C-c C-e (Outline mode): Outline Visibility.
* C-c C-e (Shell mode): Shell Mode.
* C-c C-f (GUD): Commands of GUD.
* C-c C-f (Outline mode): Outline Motion.
* C-c C-f (Picture mode): Insert in Picture.
* C-c C-f (Shell mode): Shell Mode.
* C-c C-f (TeX mode): TeX Print.
* C-c C-f C-b (Mail mode): Header Editing.
* C-c C-f C-c (Mail mode): Header Editing.
* C-c C-f C-f (Mail mode): Header Editing.
* C-c C-f C-s (Mail mode): Header Editing.
* C-c C-f C-t (Mail mode): Header Editing.
* C-c C-i (GUD): Commands of GUD.
* C-c C-i (Mail mode): Mail Mode Misc.
* C-c C-i (Outline mode): Outline Visibility.
* C-c C-k (Outline mode): Outline Visibility.
* C-c C-k (Picture mode): Rectangles in Picture.
* C-c C-k (TeX mode): TeX Print.
* C-c C-l (Calendar mode): General Calendar.
* C-c C-l (GUD): Commands of GUD.
* C-c C-l (Outline mode): Outline Visibility.
* C-c C-l (Shell mode): Shell Mode.
* C-c C-l (TeX mode): TeX Print.
* C-c C-n (C mode): Motion in C.
* C-c C-n (Fortran mode): Fortran Motion.
* C-c C-n (GUD): Commands of GUD.
* C-c C-n (Outline mode): Outline Motion.
* C-c C-n (Shell mode): Shell History Copying.
* C-c C-o (C mode): Changing Indent Style.
* C-c C-o (LaTeX mode): LaTeX Editing.
* C-c C-o (Outline mode): Outline Visibility.
* C-c C-o (Shell mode): Shell Mode.
* C-c C-p (C mode): Motion in C.
* C-c C-p (Fortran mode): Fortran Motion.
* C-c C-p (Outline mode): Outline Motion.
* C-c C-p (Shell mode): Shell History Copying.
* C-c C-p (TeX mode): TeX Print.
* C-c C-q (C mode): C Indent.
* C-c C-q (Mail mode): Citing Mail.
* C-c C-q (Outline mode): Outline Visibility.
* C-c C-q (TeX mode): TeX Print.
* C-c C-r (Fortran mode): Fortran Columns.
* C-c C-r (GUD): Commands of GUD.
* C-c C-r (Mail mode): Citing Mail.
* C-c C-r (Shell mode): Shell Mode.
* C-c C-r (TeX mode): TeX Print.
* C-c C-s (C mode): Other C Commands.
* C-c C-s (GUD): Commands of GUD.
* C-c C-s (Mail mode): Mail Sending.
* C-c C-s (Outline mode): Outline Visibility.
* C-c C-t (C mode): Hungry Delete.
* C-c C-t (GUD): Commands of GUD.
* C-c C-t (Mail mode): Mail Mode Misc.
* C-c C-t (Outline mode): Outline Visibility.
* C-c C-u (C mode): Motion in C.
* C-c C-u (Outline mode): Outline Motion.
* C-c C-u (Shell mode): Shell Mode.
* C-c C-v (TeX mode): TeX Print.
* C-c C-w (Fortran mode): Fortran Columns.
* C-c C-w (Mail mode): Mail Mode Misc.
* C-c C-w (Picture mode): Rectangles in Picture.
* C-c C-w (Shell mode): Shell Mode.
* C-c C-x (Picture mode): Rectangles in Picture.
* C-c C-y (Mail mode): Citing Mail.
* C-c C-y (Picture mode): Rectangles in Picture.
* C-c C-z (Shell mode): Shell Mode.
* C-c RET (Shell mode): Shell History Copying.
* C-c TAB (Picture mode): Tabs in Picture.
* C-c TAB (TeX mode): TeX Print.
* C-c { (TeX mode): TeX Editing.
* C-c } (TeX mode): TeX Editing.
* C-d: Deletion.
* C-d (Rmail): Rmail Deletion.
* C-d (Shell mode): Shell Mode.
* C-e: Moving Point.
* C-e (Calendar mode): Move to Beginning or End.
* C-f: Moving Point.
* C-f (Calendar mode): Calendar Unit Motion.
* C-g: Quitting.
* C-g (MS-DOS): MS-DOS Input.
* C-h: Help.
* C-h a: Apropos.
* C-h b: Misc Help.
* C-h C: Coding Systems.
* C-h c: Key Help.
* C-h C-\: Select Input Method.
* C-h C-c: Misc Help.
* C-h C-d: Misc Help.
* C-h C-f: Misc Help.
* C-h C-h: Help.
* C-h C-i: Documentation.
* C-h C-k: Misc Help.
* C-h C-p: Misc Help.
* C-h C-w: Misc Help.
* C-h F: Misc Help.
* C-h f: Name Help.
* C-h h: International Intro.
* C-h I: Select Input Method.
* C-h i: Misc Help.
* C-h k: Key Help.
* C-h L: Language Environments.
* C-h l: Misc Help.
* C-h m: Misc Help.
* C-h n: Misc Help.
* C-h p: Library Keywords.
* C-h s: Syntax.
* C-h t: Basic.
* C-h w: Name Help.
* C-j: Basic Indent.
* C-j (and major modes): Major Modes.
* C-j (Fortran mode): ForIndent Commands.
* C-j (MS-DOS): MS-DOS Input.
* C-j (TeX mode): TeX Editing.
* C-k: Killing by Lines.
* C-k (Gnus): Summary of Gnus.
* C-l: Scrolling.
* C-M-%: Query Replace.
* C-M-.: Find Tag.
* C-M-/: Dynamic Abbrevs.
* C-M-@: List Commands.
* C-M-\: Indentation Commands.
* C-M-a: Defuns.
* C-M-a (Fortran mode): Fortran Motion.
* C-M-b: List Commands.
* C-M-c: Recursive Edit.
* C-M-d: List Commands.
* C-M-d (Dired): Subdirectory Motion.
* C-M-DEL: List Commands.
* C-M-e: Defuns.
* C-M-e (Fortran mode): Fortran Motion.
* C-M-f: List Commands.
* C-M-h: Defuns.
* C-M-h (C mode): Other C Commands.
* C-M-h (Fortran mode): Fortran Motion.
* C-M-j: Multi-Line Comments.
* C-M-j (Fortran mode): ForIndent Commands.
* C-M-k: List Commands.
* C-M-l: Scrolling.
* C-M-l (Rmail): Rmail Make Summary.
* C-M-l (Shell mode): Shell Mode.
* C-M-n: List Commands.
* C-M-n (Dired): Subdirectory Motion.
* C-M-n (Rmail): Rmail Labels.
* C-M-o: Indentation Commands.
* C-M-p: List Commands.
* C-M-p (Dired): Subdirectory Motion.
* C-M-p (Rmail): Rmail Labels.
* C-M-q: Multi-line Indent.
* C-M-q (C mode): C Indent.
* C-M-q (Fortran mode): ForIndent Commands.
* C-M-r: Regexp Search.
* C-M-r (Rmail): Rmail Make Summary.
* C-M-s: Regexp Search.
* C-M-t <1>: List Commands.
* C-M-t: Transpose.
* C-M-t (Rmail): Rmail Make Summary.
* C-M-u: List Commands.
* C-M-u (Dired): Subdirectory Motion.
* C-M-v: Other Window.
* C-M-w: Appending Kills.
* C-M-x (Emacs-Lisp mode): Lisp Eval.
* C-M-x (Lisp mode): External Lisp.
* C-Mouse-2 (scroll bar): Split Window.
* C-Mouse-3: Menu Mouse Clicks.
* C-n: Moving Point.
* C-n (Calendar mode): Calendar Unit Motion.
* C-n (Dired): Dired Commands.
* C-n (Gnus Group mode): Summary of Gnus.
* C-n (Gnus Summary mode): Summary of Gnus.
* C-o: Blank Lines.
* C-o (Dired): Dired Visiting.
* C-o (Rmail): Rmail Output.
* C-p: Moving Point.
* C-p (Calendar mode): Calendar Unit Motion.
* C-p (Dired): Dired Commands.
* C-p (Gnus Group mode): Summary of Gnus.
* C-p (Gnus Summary mode): Summary of Gnus.
* C-q: Inserting Text.
* C-r: Incremental Search.
* C-s: Incremental Search.
* C-SPC: Setting Mark.
* C-t: Transpose.
* C-u: Arguments.
* C-u - C-x ;: Comment Commands.
* C-u C-@: Mark Ring.
* C-u C-SPC: Mark Ring.
* C-u C-x u: Undo.
* C-u TAB: Multi-line Indent.
* C-v: Scrolling.
* C-v (Calendar mode): Scroll Calendar.
* C-w: Other Kill Commands.
* C-x #: Emacs Server.
* C-x $: Selective Display.
* C-x (: Basic Kbd Macro.
* C-x ): Basic Kbd Macro.
* C-x +: Change Window.
* C-x -: Change Window.
* C-x .: Fill Prefix.
* C-x 0: Change Window.
* C-x 1: Change Window.
* C-x 2: Split Window.
* C-x 3: Split Window.
* C-x 4: Pop Up Window.
* C-x 4 .: Find Tag.
* C-x 4 0: Change Window.
* C-x 4 a: Change Log.
* C-x 4 b: Select Buffer.
* C-x 4 d: Dired Enter.
* C-x 4 f: Visiting.
* C-x 4 m: Sending Mail.
* C-x 5: Creating Frames.
* C-x 5 .: Find Tag.
* C-x 5 0: Misc X.
* C-x 5 2: Creating Frames.
* C-x 5 b: Select Buffer.
* C-x 5 d: Dired Enter.
* C-x 5 f: Visiting.
* C-x 5 m: Sending Mail.
* C-x 5 o: Misc X.
* C-x 5 r: Creating Frames.
* C-x 6 1: Two-Column.
* C-x 6 2: Two-Column.
* C-x 6 b: Two-Column.
* C-x 6 d: Two-Column.
* C-x 6 RET: Two-Column.
* C-x 6 s: Two-Column.
* C-x 8: Single-Byte European Support.
* C-x ;: Options for Comments.
* C-x <: Horizontal Scrolling.
* C-x < (Calendar mode): Scroll Calendar.
* C-x =: Position Info.
* C-x >: Horizontal Scrolling.
* C-x > (Calendar mode): Scroll Calendar.
* C-x [: Pages.
* C-x [ (Calendar mode): Calendar Unit Motion.
* C-x ]: Pages.
* C-x ] (Calendar mode): Calendar Unit Motion.
* C-x ^: Change Window.
* C-x `: Compilation Mode.
* C-x a g: Defining Abbrevs.
* C-x a i g: Defining Abbrevs.
* C-x a i l: Defining Abbrevs.
* C-x a l: Defining Abbrevs.
* C-x b: Select Buffer.
* C-x C-<SPC>: Global Mark Ring.
* C-x C-a (GUD): Commands of GUD.
* C-x C-b: List Buffers.
* C-x C-c: Exiting.
* C-x C-d: Directories.
* C-x C-e: Lisp Eval.
* C-x C-f: Visiting.
* C-x C-k: Basic Kbd Macro.
* C-x C-l: Case.
* C-x C-n: Moving Point.
* C-x C-o: Blank Lines.
* C-x C-p: Pages.
* C-x C-q: Misc Buffer.
* C-x C-q (Version Control): Basic VC Editing.
* C-x C-r: Visiting.
* C-x C-s: Saving.
* C-x C-t: Transpose.
* C-x C-u: Case.
* C-x C-v: Visiting.
* C-x C-w: Saving.
* C-x C-x: Setting Mark.
* C-x C-z: External Lisp.
* C-x d: Dired Enter.
* C-x DEL: Sentences.
* C-x e: Basic Kbd Macro.
* C-x ESC ESC: Repetition.
* C-x f: Fill Commands.
* C-x h: Marking Objects.
* C-x k: Kill Buffer.
* C-x l: Pages.
* C-x m: Sending Mail.
* C-x n d: Narrowing.
* C-x n d (Fortran mode): Fortran Misc.
* C-x n n: Narrowing.
* C-x n p: Narrowing.
* C-x n w: Narrowing.
* C-x o: Other Window.
* C-x q: Kbd Macro Query.
* C-x r +: RegNumbers.
* C-x r b: Bookmarks.
* C-x r d: Rectangles.
* C-x r f: RegConfig.
* C-x r i: RegText.
* C-x r j: RegPos.
* C-x r k: Rectangles.
* C-x r l: Bookmarks.
* C-x r m: Bookmarks.
* C-x r n: RegNumbers.
* C-x r o: Rectangles.
* C-x r r: RegRect.
* C-x r s: RegText.
* C-x r SPC: RegPos.
* C-x r t: Rectangles.
* C-x r w: RegConfig.
* C-x r y: Rectangles.
* C-x RET: International Intro.
* C-x RET c: Specify Coding.
* C-x RET C-\: Select Input Method.
* C-x RET f: Specify Coding.
* C-x RET k: Specify Coding.
* C-x RET p: Specify Coding.
* C-x RET t: Specify Coding.
* C-x RET X: Specify Coding.
* C-x RET x: Specify Coding.
* C-x s: Saving.
* C-x SPC: Commands of GUD.
* C-x TAB: Indentation Commands.
* C-x TAB (Enriched mode): Format Indentation.
* C-x u: Undo.
* C-x v =: Old Versions.
* C-x v a: Change Logs and VC.
* C-x v c: VC Undo.
* C-x v d: VC Dired Mode.
* C-x v g: Old Versions.
* C-x v h: Version Headers.
* C-x v i: Registering.
* C-x v l: VC Status.
* C-x v m: Merging.
* C-x v r: Making Snapshots.
* C-x v s: Making Snapshots.
* C-x v u: VC Undo.
* C-x v v: Basic VC Editing.
* C-x v ~: Old Versions.
* C-x z: Repeating.
* C-x }: Change Window.
* C-y: Kill Ring.
* C-z: Exiting.
* C-z (X windows): Misc X.
* d (Calendar mode): Diary Commands.
* D (Dired): Operating on Files.
* d (Dired): Dired Deletion.
* d (Rmail): Rmail Deletion.
* DEL: Deletion.
* DEL (and major modes): Major Modes.
* DEL (Dired): Dired Deletion.
* DEL (Gnus): Summary of Gnus.
* DEL (MS-DOS): MS-DOS Input.
* DEL (programming modes): Program Modes.
* DEL (Rmail): Rmail Scrolling.
* DELETE: Mouse Commands.
* DOWN: Moving Point.
* e (Rmail): Rmail Editing.
* ESC a: Motion in C.
* ESC e: Motion in C.
* ESC ESC ESC: Quitting.
* f (Dired): Dired Visiting.
* f (Rmail): Rmail Reply.
* F1: Help.
* F10: Menu Bar.
* F2 1: Two-Column.
* F2 2: Two-Column.
* F2 b: Two-Column.
* F2 d: Two-Column.
* F2 RET: Two-Column.
* F2 s: Two-Column.
* g (Dired): Dired Updating.
* G (Dired): Operating on Files.
* g (Rmail): Rmail Files.
* g CHAR (Calendar mode): From Other Calendar.
* g d (Calendar mode): Specified Dates.
* g m (Calendar mode): Mayan Calendar.
* h (Calendar mode): Holidays.
* H (Dired): Operating on Files.
* h (Rmail): Rmail Make Summary.
* Help: Help.
* i (Dired): Subdirectories in Dired.
* i (Rmail): Rmail Files.
* i a (Calendar mode): Special Diary Entries.
* i b (Calendar mode): Special Diary Entries.
* i c (Calendar mode): Special Diary Entries.
* i d (Calendar mode): Adding to Diary.
* i m (Calendar mode): Adding to Diary.
* i w (Calendar mode): Adding to Diary.
* i y (Calendar mode): Adding to Diary.
* j (Rmail): Rmail Motion.
* k (Dired): Dired Updating.
* k (Rmail): Rmail Labels.
* l (Dired): Dired Updating.
* L (Dired): Operating on Files.
* l (Gnus Group mode): Summary of Gnus.
* L (Gnus Group mode): Summary of Gnus.
* l (Rmail): Rmail Make Summary.
* LEFT: Moving Point.
* m (Calendar mode): Diary Commands.
* M (Calendar mode): Lunar Phases.
* M (Dired): Operating on Files.
* m (Dired): Marks vs Flags.
* m (Rmail): Rmail Reply.
* M-!: Single Shell.
* M-$: Spelling.
* M-$ (Dired): Hiding Subdirectories.
* M-%: Query Replace.
* M-': Expanding Abbrevs.
* M-(: Balanced Editing.
* M-): Balanced Editing.
* M-*: Find Tag.
* M-,: Tags Search.
* M--: Arguments.
* M-- M-c: Fixing Case.
* M-- M-l: Fixing Case.
* M-- M-u: Fixing Case.
* M-.: Find Tag.
* M-/: Dynamic Abbrevs.
* M-1: Arguments.
* M-:: Lisp Eval.
* M-;: Comment Commands.
* M-<: Moving Point.
* M-< (Calendar mode): Move to Beginning or End.
* M-=: Position Info.
* M-= (Calendar mode): Counting Days.
* M-= (Dired): Comparison in Dired.
* M->: Moving Point.
* M-> (Calendar mode): Move to Beginning or End.
* M-? (Nroff mode): Nroff Mode.
* M-? (Shell mode): Shell Mode.
* M-@: Words.
* M-\: Deletion.
* M-^: Indentation Commands.
* M-^ (Fortran mode): ForIndent Commands.
* M-`: Menu Bar.
* M-a: Sentences.
* M-a (Calendar mode): Move to Beginning or End.
* M-b: Words.
* M-c: Case.
* M-d: Words.
* M-DEL: Words.
* M-Drag-Mouse-1: Secondary Selection.
* M-e: Sentences.
* M-e (Calendar mode): Move to Beginning or End.
* M-f: Words.
* M-g b (Enriched mode): Format Faces.
* M-g d (Enriched mode): Format Faces.
* M-g i (Enriched mode): Format Faces.
* M-g l (Enriched mode): Format Faces.
* M-g M-g: Font Lock.
* M-g o (Enriched mode): Format Faces.
* M-g u (Enriched mode): Format Faces.
* M-h: Paragraphs.
* M-i: Tab Stops.
* M-j c (Enriched mode): Format Justification.
* M-j f (Enriched mode): Format Justification.
* M-j l (Enriched mode): Format Justification.
* M-j r (Enriched mode): Format Justification.
* M-j u (Enriched mode): Format Justification.
* M-k: Sentences.
* M-l: Case.
* M-m: Indentation Commands.
* M-m (Rmail): Rmail Reply.
* M-Mouse-1: Secondary Selection.
* M-Mouse-2: Secondary Selection.
* M-Mouse-3: Secondary Selection.
* M-n (minibuffer history): Minibuffer History.
* M-n (Nroff mode): Nroff Mode.
* M-n (Rmail): Rmail Motion.
* M-n (Shell mode): Shell Ring.
* M-p (minibuffer history): Minibuffer History.
* M-p (Nroff mode): Nroff Mode.
* M-p (Rmail): Rmail Motion.
* M-p (Shell mode): Shell Ring.
* M-q: Fill Commands.
* M-q (C mode): Other C Commands.
* M-r: Moving Point.
* M-r (minibuffer history): Minibuffer History.
* M-r (Shell mode): Shell Ring.
* M-S (Enriched mode): Format Justification.
* M-s (Gnus Summary mode): Summary of Gnus.
* M-s (minibuffer history): Minibuffer History.
* M-s (Rmail): Rmail Motion.
* M-s (Shell mode): Shell Ring.
* M-s (Text mode): Fill Commands.
* M-SPC: Deletion.
* M-t <1>: Words.
* M-t: Transpose.
* M-TAB: Symbol Completion.
* M-TAB (customization buffer): Changing an Option.
* M-TAB (Mail mode): Header Editing.
* M-TAB (Picture mode): Tabs in Picture.
* M-TAB (Text mode): Text Mode.
* M-u: Case.
* M-v: Scrolling.
* M-v (Calendar mode): Scroll Calendar.
* M-w: Kill Ring.
* M-x: M-x.
* M-y: Earlier Kills.
* M-z: Other Kill Commands.
* M-{: Paragraphs.
* M-{ (Calendar mode): Calendar Unit Motion.
* M-|: Single Shell.
* M-}: Paragraphs.
* M-} (Calendar mode): Calendar Unit Motion.
* M-~: Saving.
* Mouse-1: Mouse Commands.
* Mouse-2: Mouse Commands.
* Mouse-2 (selection): Mouse References.
* Mouse-3: Mouse Commands.
* n (Gnus): Summary of Gnus.
* n (Rmail): Rmail Motion.
* NEXT: Scrolling.
* o (Calendar mode): Specified Dates.
* O (Dired): Operating on Files.
* o (Dired): Dired Visiting.
* o (Rmail): Rmail Output.
* p (Calendar mode): To Other Calendar.
* P (Dired): Operating on Files.
* p (Gnus): Summary of Gnus.
* p (Rmail): Rmail Motion.
* p d (Calendar mode): General Calendar.
* PRIOR: Scrolling.
* q (Calendar mode): General Calendar.
* Q (Dired): Operating on Files.
* q (Gnus Group mode): Summary of Gnus.
* q (Rmail summary): Rmail Summary Edit.
* Q (Rmail summary): Rmail Summary Edit.
* q (Rmail): Rmail Basics.
* R (Dired): Operating on Files.
* r (Rmail): Rmail Reply.
* RET: Inserting Text.
* RET (Dired): Dired Visiting.
* RET (Occur mode): Other Repeating Search.
* RET (Shell mode): Shell Mode.
* RIGHT: Moving Point.
* s (Calendar mode): Diary Commands.
* S (Calendar mode): Sunrise/Sunset.
* s (Dired): Dired Updating.
* S (Dired): Operating on Files.
* s (Gnus Summary mode): Summary of Gnus.
* s (Rmail): Rmail Basics.
* S-<TAB> (Help mode): Help Mode.
* S-Mouse-1: Frame Parameters.
* S-TAB (customization buffer): Changing an Option.
* SPC: Completion Commands.
* SPC (Calendar mode): General Calendar.
* SPC (Dired): Dired Commands.
* SPC (Gnus): Summary of Gnus.
* SPC (Rmail): Rmail Scrolling.
* t (Calendar mode): LaTeX Calendar.
* t (Rmail): Rmail Display.
* TAB: Indentation.
* TAB (and major modes): Major Modes.
* TAB (completion): Completion Example.
* TAB (customization buffer): Changing an Option.
* TAB (GUD): Commands of GUD.
* TAB (programming modes): Basic Indent.
* TAB (Shell mode): Shell Mode.
* TAB (Text mode): Text Mode.
* u (Calendar mode): Holidays.
* u (Dired deletion): Dired Deletion.
* u (Dired): Marks vs Flags.
* u (Gnus Group mode): Summary of Gnus.
* u (Rmail): Rmail Deletion.
* UP: Moving Point.
* v (Dired): Dired Visiting.
* w (Rmail): Rmail Output.
* x (Calendar mode): Holidays.
* x (Dired): Dired Deletion.
* x (Rmail): Rmail Deletion.
* Z (Dired): Operating on Files.
* ~ (Dired): Flagging Many Files.
Command and Function Index
**************************
* Menu:
* 2C-associate-buffer: Two-Column.
* 2C-dissociate: Two-Column.
* 2C-merge: Two-Column.
* 2C-newline: Two-Column.
* 2C-split: Two-Column.
* 2C-two-columns: Two-Column.
* abbrev-mode: Abbrev Concepts.
* abbrev-prefix-mark: Expanding Abbrevs.
* abort-recursive-edit: Quitting.
* add-change-log-entry-other-window: Change Log.
* add-global-abbrev: Defining Abbrevs.
* add-mode-abbrev: Defining Abbrevs.
* add-name-to-file: Misc File Ops.
* add-untranslated-filesystem: Text and Binary.
* american-calendar: Date Formats.
* append-next-kill: Appending Kills.
* append-to-buffer: Accumulating Text.
* append-to-file: Accumulating Text.
* apply-macro-to-region-lines: Basic Kbd Macro.
* appt-add: Appointments.
* appt-delete: Appointments.
* appt-make-list: Appointments.
* apropos: Apropos.
* apropos-command: Apropos.
* apropos-documentation: Apropos.
* apropos-value: Apropos.
* apropos-variable: Apropos.
* ask-user-about-lock: Interlocking.
* auto-compression-mode: Compressed Files.
* auto-fill-mode: Auto Fill.
* auto-lower-mode: Frame Parameters.
* auto-raise-mode: Frame Parameters.
* auto-save-mode: Auto Save Control.
* back-to-indentation: Indentation Commands.
* backward-char: Moving Point.
* backward-delete-char-untabify: Program Modes.
* backward-kill-sentence: Sentences.
* backward-kill-sexp: List Commands.
* backward-kill-word: Words.
* backward-list: List Commands.
* backward-page: Pages.
* backward-paragraph: Paragraphs.
* backward-sentence: Sentences.
* backward-sexp: List Commands.
* backward-text-line: Nroff Mode.
* backward-up-list: List Commands.
* backward-word: Words.
* balance-windows: Change Window.
* beginning-of-buffer: Moving Point.
* beginning-of-defun: Defuns.
* beginning-of-fortran-subprogram: Fortran Motion.
* beginning-of-line: Moving Point.
* binary-overwrite-mode: Minor Modes.
* blackbox: Amusements.
* bookmark-delete: Bookmarks.
* bookmark-insert: Bookmarks.
* bookmark-insert-location: Bookmarks.
* bookmark-jump: Bookmarks.
* bookmark-load: Bookmarks.
* bookmark-save: Bookmarks.
* bookmark-set: Bookmarks.
* bookmark-write: Bookmarks.
* buffer-menu: Several Buffers.
* c-add-style: C Indent Styles.
* c-backslash-region: Other C Commands.
* c-backward-conditional: Motion in C.
* c-backward-into-nomenclature: Motion in C.
* c-beginning-of-statement: Motion in C.
* c-end-of-statement: Motion in C.
* c-fill-paragraph: Other C Commands.
* c-forward-conditional: Motion in C.
* c-forward-into-nomenclature: Motion in C.
* c-indent-command: C Indent.
* c-indent-defun: C Indent.
* c-indent-exp: C Indent.
* c-indent-line: Basic Indent.
* c-macro-expand: Other C Commands.
* c-mark-function <1>: Other C Commands.
* c-mark-function: Defuns.
* c-scope-operator: Electric C.
* c-set-offset: Changing Indent Style.
* c-set-style: C Indent Styles.
* c-show-syntactic-information: Other C Commands.
* c-toggle-auto-hungry-state: Hungry Delete.
* c-toggle-auto-state: Electric C.
* c-toggle-hungry-state: Hungry Delete.
* c-up-conditional: Motion in C.
* calendar: Calendar/Diary.
* calendar-backward-day: Calendar Unit Motion.
* calendar-backward-month: Calendar Unit Motion.
* calendar-backward-week: Calendar Unit Motion.
* calendar-beginning-of-month: Move to Beginning or End.
* calendar-beginning-of-week: Move to Beginning or End.
* calendar-beginning-of-year: Move to Beginning or End.
* calendar-count-days-region: Counting Days.
* calendar-cursor-holidays: Holidays.
* calendar-end-of-month: Move to Beginning or End.
* calendar-end-of-week: Move to Beginning or End.
* calendar-end-of-year: Move to Beginning or End.
* calendar-forward-day: Calendar Unit Motion.
* calendar-forward-month: Calendar Unit Motion.
* calendar-forward-week: Calendar Unit Motion.
* calendar-forward-year: Calendar Unit Motion.
* calendar-goto-astro-day-number: From Other Calendar.
* calendar-goto-chinese-date: From Other Calendar.
* calendar-goto-coptic-date: From Other Calendar.
* calendar-goto-date: Specified Dates.
* calendar-goto-ethiopic-date: From Other Calendar.
* calendar-goto-french-date: From Other Calendar.
* calendar-goto-hebrew-date: From Other Calendar.
* calendar-goto-islamic-date: From Other Calendar.
* calendar-goto-iso-date: From Other Calendar.
* calendar-goto-julian-date: From Other Calendar.
* calendar-goto-mayan-long-count-date: Mayan Calendar.
* calendar-goto-persian-date: From Other Calendar.
* calendar-goto-today: Specified Dates.
* calendar-next-calendar-round-date: Mayan Calendar.
* calendar-next-haab-date: Mayan Calendar.
* calendar-next-tzolkin-date: Mayan Calendar.
* calendar-other-month: Specified Dates.
* calendar-phases-of-moon: Lunar Phases.
* calendar-previous-haab-date: Mayan Calendar.
* calendar-previous-tzolkin-date: Mayan Calendar.
* calendar-print-astro-day-number: To Other Calendar.
* calendar-print-chinese-date: To Other Calendar.
* calendar-print-coptic-date: To Other Calendar.
* calendar-print-day-of-year: General Calendar.
* calendar-print-ethiopic-date: To Other Calendar.
* calendar-print-french-date: To Other Calendar.
* calendar-print-hebrew-date: To Other Calendar.
* calendar-print-islamic-date: To Other Calendar.
* calendar-print-iso-date: To Other Calendar.
* calendar-print-julian-date: To Other Calendar.
* calendar-print-mayan-date: To Other Calendar.
* calendar-print-persian-date: To Other Calendar.
* calendar-sunrise-sunset: Sunrise/Sunset.
* calendar-unmark: Holidays.
* call-last-kbd-macro: Basic Kbd Macro.
* capitalize-word: Case.
* cd: File Names.
* center-line: Fill Commands.
* change-log-mode: Change Log.
* choose-completion: Completion Commands.
* clean-buffer-list: Kill Buffer.
* clear-rectangle: Rectangles.
* codepage-setup: MS-DOS and MULE.
* column-number-mode: Optional Mode Line.
* comint-bol: Shell Mode.
* comint-continue-subjob: Shell Mode.
* comint-copy-old-input: Shell History Copying.
* comint-delchar-or-maybe-eof: Shell Mode.
* comint-dynamic-complete: Shell Mode.
* comint-dynamic-complete-variable: Shell Options.
* comint-dynamic-list-filename...: Shell Mode.
* comint-dynamic-list-input-ring: Shell Mode.
* comint-get-next-from-history: Shell Ring.
* comint-interrupt-subjob: Shell Mode.
* comint-kill-input: Shell Mode.
* comint-kill-output: Shell Mode.
* comint-magic-space: History References.
* comint-next-input: Shell Ring.
* comint-next-matching-input: Shell Ring.
* comint-next-prompt: Shell History Copying.
* comint-previous-input: Shell Ring.
* comint-previous-matching-input: Shell Ring.
* comint-previous-prompt: Shell History Copying.
* comint-quit-subjob: Shell Mode.
* comint-run: Shell Mode.
* comint-send-input: Shell Mode.
* comint-show-maximum-output: Shell Mode.
* comint-show-output: Shell Mode.
* comint-stop-subjob: Shell Mode.
* comint-strip-ctrl-m: Shell Mode.
* comint-truncate-buffer: Shell Mode.
* comment-region: Multi-Line Comments.
* compare-windows: Comparing Files.
* compile: Compilation.
* compile (MS-DOS): MS-DOS Processes.
* compile-goto-error: Compilation Mode.
* complete-symbol: Symbol Completion.
* compose-mail: Sending Mail.
* compose-mail-other-frame: Sending Mail.
* compose-mail-other-window: Sending Mail.
* copy-file: Misc File Ops.
* copy-rectangle-to-register: RegRect.
* copy-to-buffer: Accumulating Text.
* copy-to-register: RegText.
* count-lines-page: Pages.
* count-lines-region: Position Info.
* count-matches: Other Repeating Search.
* count-text-lines: Nroff Mode.
* cpp-highlight-buffer: Other C Commands.
* create-fontset-from-fontset-spec: Defining Fontsets.
* customize: Easy Customization.
* customize-apropos: Specific Customization.
* customize-browse: Customization Groups.
* customize-changed-options: Specific Customization.
* customize-customized: Specific Customization.
* customize-face: Specific Customization.
* customize-group: Specific Customization.
* customize-option: Specific Customization.
* customize-saved: Specific Customization.
* dabbrev-completion: Dynamic Abbrevs.
* dabbrev-expand: Dynamic Abbrevs.
* dbx: Starting GUD.
* debug_print: Checklist.
* default-value: Locals.
* define-abbrevs: Saving Abbrevs.
* define-key: Init Rebinding.
* define-mail-abbrev: Mail Aliases.
* define-mail-alias: Mail Aliases.
* delete-backward-char: Deletion.
* delete-blank-lines: Blank Lines.
* delete-char: Deletion.
* delete-file: Misc File Ops.
* delete-frame: Misc X.
* delete-horizontal-space: Deletion.
* delete-indentation: Indentation Commands.
* delete-matching-lines: Other Repeating Search.
* delete-non-matching-lines: Other Repeating Search.
* delete-other-windows: Change Window.
* delete-rectangle: Rectangles.
* delete-whitespace-rectangle: Rectangles.
* delete-window: Change Window.
* describe-bindings: Misc Help.
* describe-coding-system: Coding Systems.
* describe-copying: Misc Help.
* describe-distribution: Misc Help.
* describe-function: Name Help.
* describe-input-method: Select Input Method.
* describe-key: Key Help.
* describe-key-briefly: Key Help.
* describe-language-environment: Language Environments.
* describe-mode: Misc Help.
* describe-no-warranty: Misc Help.
* describe-project: Misc Help.
* describe-syntax: Syntax.
* desktop-save: Saving Emacs Sessions.
* diary: Diary Commands.
* diary-anniversary: Special Diary Entries.
* diary-block: Special Diary Entries.
* diary-cyclic: Special Diary Entries.
* diary-float: Special Diary Entries.
* diary-mail-entries: Diary Commands.
* diff: Comparing Files.
* diff-backup: Comparing Files.
* digit-argument: Arguments.
* dired: Dired Enter.
* dired-backup-diff: Comparison in Dired.
* dired-change-marks: Marks vs Flags.
* dired-clean-directory: Flagging Many Files.
* dired-create-directory: Operating on Files.
* dired-diff: Comparison in Dired.
* dired-display-file: Dired Visiting.
* dired-do-byte-compile: Operating on Files.
* dired-do-chgrp: Operating on Files.
* dired-do-chmod: Operating on Files.
* dired-do-chown: Operating on Files.
* dired-do-compress: Operating on Files.
* dired-do-copy: Operating on Files.
* dired-do-copy-regexp: Transforming File Names.
* dired-do-delete: Operating on Files.
* dired-do-hardlink: Operating on Files.
* dired-do-hardlink-regexp: Transforming File Names.
* dired-do-kill-lines: Dired Updating.
* dired-do-load: Operating on Files.
* dired-do-print: Operating on Files.
* dired-do-query-replace: Operating on Files.
* dired-do-redisplay: Dired Updating.
* dired-do-rename: Operating on Files.
* dired-do-rename-regexp: Transforming File Names.
* dired-do-search: Operating on Files.
* dired-do-shell-command: Shell Commands in Dired.
* dired-do-symlink: Operating on Files.
* dired-do-symlink-regexp: Transforming File Names.
* dired-do-toggle: Marks vs Flags.
* dired-downcase: Transforming File Names.
* dired-expunge: Dired Deletion.
* dired-find-file: Dired Visiting.
* dired-find-file-other-window: Dired Visiting.
* dired-flag-auto-save-files: Flagging Many Files.
* dired-flag-backup-files: Flagging Many Files.
* dired-flag-file-deletion: Dired Deletion.
* dired-flag-files-regexp: Flagging Many Files.
* dired-flag-garbage-files: Flagging Many Files.
* dired-hide-all: Hiding Subdirectories.
* dired-hide-subdir: Hiding Subdirectories.
* dired-mark: Marks vs Flags.
* dired-mark-directories: Marks vs Flags.
* dired-mark-executables: Marks vs Flags.
* dired-mark-files-containing-regexp: Marks vs Flags.
* dired-mark-files-regexp: Marks vs Flags.
* dired-mark-subdir-files: Marks vs Flags.
* dired-mark-symlinks: Marks vs Flags.
* dired-maybe-insert-subdir: Subdirectories in Dired.
* dired-mouse-find-file-other-window: Dired Visiting.
* dired-next-dirline: Subdirectory Motion.
* dired-next-marked-file: Marks vs Flags.
* dired-next-subdir: Subdirectory Motion.
* dired-other-frame: Dired Enter.
* dired-other-window: Dired Enter.
* dired-prev-dirline: Subdirectory Motion.
* dired-prev-marked-file: Marks vs Flags.
* dired-prev-subdir: Subdirectory Motion.
* dired-sort-toggle-or-edit: Dired Updating.
* dired-tree-down: Subdirectory Motion.
* dired-tree-up: Subdirectory Motion.
* dired-undo: Marks vs Flags.
* dired-unmark: Marks vs Flags.
* dired-unmark-all-files: Marks vs Flags.
* dired-unmark-all-files-no-query: Marks vs Flags.
* dired-unmark-backward: Marks vs Flags.
* dired-upcase: Transforming File Names.
* dired-view-file: Dired Visiting.
* dirs: Interactive Shell.
* dirtrack-mode: Interactive Shell.
* disable-command: Disabling.
* display-time: Optional Mode Line.
* dissociated-press: Dissociated Press.
* do-auto-save: Auto Save Control.
* doctor: Total Frustration.
* down-list: List Commands.
* downcase-region: Case.
* downcase-word: Case.
* dunnet: Amusements.
* edit-abbrevs: Editing Abbrevs.
* edit-kbd-macro: Basic Kbd Macro.
* edit-picture: Picture.
* edit-tab-stops: Tab Stops.
* edit-tab-stops-note-changes: Tab Stops.
* edt-emulation-off: Emulation.
* edt-emulation-on: Emulation.
* eldoc-mode: Documentation.
* electric-nroff-mode: Nroff Mode.
* emacs-lisp-mode: Lisp Eval.
* emacs-version: Understanding Bug Reporting.
* emerge-auto-advance-mode: Submodes of Emerge.
* emerge-buffers: Overview of Emerge.
* emerge-buffers-with-ancestor: Overview of Emerge.
* emerge-files: Overview of Emerge.
* emerge-files-with-ancestor: Overview of Emerge.
* emerge-skip-prefers-mode: Submodes of Emerge.
* enable-command: Disabling.
* enable-flow-control: Unasked-for Search.
* enable-flow-control-on: Unasked-for Search.
* enable-local-eval: File Variables.
* enable-local-variables: File Variables.
* end-kbd-macro: Basic Kbd Macro.
* end-of-buffer: Moving Point.
* end-of-defun: Defuns.
* end-of-fortran-subprogram: Fortran Motion.
* end-of-line: Moving Point.
* enlarge-window: Change Window.
* enlarge-window-horizontally: Change Window.
* enriched-mode: Requesting Formatted Text.
* european-calendar: Date Formats.
* eval-current-buffer: Lisp Eval.
* eval-defun: Lisp Eval.
* eval-expression: Lisp Eval.
* eval-last-sexp: Lisp Eval.
* eval-region: Lisp Eval.
* exchange-point-and-mark: Setting Mark.
* execute-extended-command: M-x.
* exit-calendar: General Calendar.
* exit-recursive-edit: Recursive Edit.
* expand-abbrev: Expanding Abbrevs.
* expand-mail-aliases: Mail Aliases.
* expand-region-abbrevs: Expanding Abbrevs.
* facemenu-remove-all: Editing Format Info.
* facemenu-remove-props: Editing Format Info.
* facemenu-set-background: Format Colors.
* facemenu-set-bold: Format Faces.
* facemenu-set-bold-italic: Format Faces.
* facemenu-set-default: Format Faces.
* facemenu-set-face: Format Faces.
* facemenu-set-foreground: Format Colors.
* facemenu-set-italic: Format Faces.
* facemenu-set-underline: Format Faces.
* fast-lock-mode: Fast Lock Mode.
* fill-individual-paragraphs: Fill Prefix.
* fill-nonuniform-paragraphs: Fill Prefix.
* fill-paragraph: Fill Commands.
* fill-region: Fill Commands.
* fill-region-as-paragraph: Fill Commands.
* find-alternate-file: Visiting.
* find-dired: Dired and Find.
* find-file: Visiting.
* find-file-binary: Text and Binary.
* find-file-literally: Visiting.
* find-file-other-frame: Visiting.
* find-file-other-window: Visiting.
* find-file-read-only: Visiting.
* find-file-read-only-other-frame: Creating Frames.
* find-file-text: Text and Binary.
* find-grep-dired: Dired and Find.
* find-name-dired: Dired and Find.
* find-tag: Find Tag.
* find-tag-other-frame: Find Tag.
* find-tag-other-window: Find Tag.
* find-tag-regexp: Find Tag.
* finder-by-keyword: Library Keywords.
* flush-lines: Other Repeating Search.
* flyspell-mode: Spelling.
* font-lock-add-keywords: Font Lock.
* font-lock-fontify-block: Font Lock.
* font-lock-mode: Font Lock.
* format-find-file: Forcing Enriched Mode.
* fortran-auto-fill-mode: Fortran Autofill.
* fortran-column-ruler: Fortran Columns.
* fortran-comment-region: Fortran Comments.
* fortran-indent-line: ForIndent Commands.
* fortran-indent-new-line: ForIndent Commands.
* fortran-indent-subprogram: ForIndent Commands.
* fortran-join-line: ForIndent Commands.
* fortran-mode: Fortran.
* fortran-narrow-to-subprogram: Fortran Misc.
* fortran-next-statement: Fortran Motion.
* fortran-previous-statement: Fortran Motion.
* fortran-split-line: ForIndent Commands.
* fortran-window-create: Fortran Columns.
* forward-char: Moving Point.
* forward-list: List Commands.
* forward-page: Pages.
* forward-paragraph: Paragraphs.
* forward-sentence: Sentences.
* forward-sexp: List Commands.
* forward-text-line: Nroff Mode.
* forward-word: Words.
* frame-configuration-to-register: RegConfig.
* gdb: Starting GUD.
* global-font-lock-mode: Font Lock.
* global-set-key: Rebinding.
* global-unset-key: Rebinding.
* gnus: Gnus.
* gnus-group-exit: Summary of Gnus.
* gnus-group-kill-group: Summary of Gnus.
* gnus-group-list-all-groups: Summary of Gnus.
* gnus-group-list-groups: Summary of Gnus.
* gnus-group-next-group: Summary of Gnus.
* gnus-group-next-unread-group: Summary of Gnus.
* gnus-group-prev-group: Summary of Gnus.
* gnus-group-prev-unread-group: Summary of Gnus.
* gnus-group-read-group: Summary of Gnus.
* gnus-group-unsubscribe-current-group: Summary of Gnus.
* gnus-summary-isearch-article: Summary of Gnus.
* gnus-summary-next-subject: Summary of Gnus.
* gnus-summary-next-unread-article: Summary of Gnus.
* gnus-summary-prev-page: Summary of Gnus.
* gnus-summary-prev-subject: Summary of Gnus.
* gnus-summary-prev-unread-article: Summary of Gnus.
* gnus-summary-search-article-forward: Summary of Gnus.
* gomoku: Amusements.
* goto-char: Moving Point.
* goto-line: Moving Point.
* grep: Grep Searching.
* grep (MS-DOS): MS-DOS Processes.
* grep-find: Grep Searching.
* gud-cont: Commands of GUD.
* gud-def: GUD Customization.
* gud-down: Commands of GUD.
* gud-finish: Commands of GUD.
* gud-gdb-complete-command: Commands of GUD.
* gud-next: Commands of GUD.
* gud-refresh: Commands of GUD.
* gud-remove: Commands of GUD.
* gud-step: Commands of GUD.
* gud-stepi: Commands of GUD.
* gud-tbreak: Commands of GUD.
* gud-up: Commands of GUD.
* hanoi: Amusements.
* help-command: Help.
* help-for-help: Help.
* help-next-ref: Help Mode.
* help-previous-ref: Help Mode.
* help-with-tutorial: Basic.
* hide-body: Outline Visibility.
* hide-entry: Outline Visibility.
* hide-leaves: Outline Visibility.
* hide-other: Outline Visibility.
* hide-sublevels: Outline Visibility.
* hide-subtree: Outline Visibility.
* highlight-changes-mode: Highlight Changes.
* holidays: Holidays.
* hscroll-mode: Horizontal Scrolling.
* iconify-or-deiconify-frame: Misc X.
* ielm: Lisp Interaction.
* increase-left-margin: Format Indentation.
* increment-register: RegNumbers.
* indent-for-comment: Comment Commands.
* indent-new-comment-line: Multi-Line Comments.
* indent-region: Indentation Commands.
* indent-relative: Indentation Commands.
* indent-rigidly: Indentation Commands.
* indent-sexp: Multi-line Indent.
* info: Misc Help.
* Info-goto-emacs-command-node: Misc Help.
* Info-goto-emacs-key-command-node: Misc Help.
* info-lookup-file: Documentation.
* info-lookup-symbol: Documentation.
* insert-abbrevs: Saving Abbrevs.
* insert-anniversary-diary-entry: Special Diary Entries.
* insert-block-diary-entry: Special Diary Entries.
* insert-cyclic-diary-entry: Special Diary Entries.
* insert-diary-entry: Adding to Diary.
* insert-file: Misc File Ops.
* insert-kbd-macro: Save Kbd Macro.
* insert-monthly-diary-entry: Adding to Diary.
* insert-parentheses: Balanced Editing.
* insert-register: RegText.
* insert-weekly-diary-entry: Adding to Diary.
* insert-yearly-diary-entry: Adding to Diary.
* inverse-add-global-abbrev: Defining Abbrevs.
* inverse-add-mode-abbrev: Defining Abbrevs.
* isearch-backward: Incremental Search.
* isearch-backward-regexp: Regexp Search.
* isearch-forward: Incremental Search.
* isearch-forward-regexp: Regexp Search.
* ispell-buffer: Spelling.
* ispell-complete-word: Spelling.
* ispell-kill-ispell: Spelling.
* ispell-message: Mail Mode Misc.
* ispell-region: Spelling.
* ispell-word: Spelling.
* jdb: Starting GUD.
* jump-to-register: RegPos.
* just-one-space: Deletion.
* kbd-macro-query: Kbd Macro Query.
* keep-lines: Other Repeating Search.
* keyboard-escape-quit: Quitting.
* keyboard-translate: Keyboard Translations.
* kill-all-abbrevs: Defining Abbrevs.
* kill-buffer: Kill Buffer.
* kill-buffer-and-window: Change Window.
* kill-comment: Comment Commands.
* kill-compilation: Compilation.
* kill-line: Killing by Lines.
* kill-local-variable: Locals.
* kill-rectangle: Rectangles.
* kill-region: Other Kill Commands.
* kill-ring-save: Kill Ring.
* kill-sentence: Sentences.
* kill-sexp: List Commands.
* kill-some-buffers: Kill Buffer.
* kill-word: Words.
* latex-mode: TeX Mode.
* lazy-lock-mode: Lazy Lock Mode.
* line-number-mode: Optional Mode Line.
* lisp-complete-symbol: Symbol Completion.
* lisp-eval-defun: External Lisp.
* lisp-indent-line: Basic Indent.
* lisp-interaction-mode: Lisp Interaction.
* lisp-mode: External Lisp.
* list-abbrevs: Editing Abbrevs.
* list-bookmarks: Bookmarks.
* list-buffers: List Buffers.
* list-calendar-holidays: Holidays.
* list-coding-systems: Coding Systems.
* list-command-history: Repetition.
* list-directory: Directories.
* list-faces-display: Faces.
* list-holidays: Holidays.
* list-input-methods: Select Input Method.
* list-matching-lines: Other Repeating Search.
* list-tags: List Tags.
* list-text-properties-at: Editing Format Info.
* list-yahrzeit-dates: From Other Calendar.
* load: Lisp Libraries.
* load-file: Lisp Libraries.
* load-library: Lisp Libraries.
* local-set-key: Rebinding.
* local-unset-key: Rebinding.
* lpr-buffer: Hardcopy.
* lpr-region: Hardcopy.
* mail-attach-file: Mail Mode Misc.
* mail-bcc: Header Editing.
* mail-cc: Header Editing.
* mail-complete: Header Editing.
* mail-fcc: Header Editing.
* mail-fill-yanked-message: Citing Mail.
* mail-interactive-insert-alias: Mail Aliases.
* mail-send: Mail Sending.
* mail-send-and-exit: Mail Sending.
* mail-signature: Mail Mode Misc.
* mail-subject: Header Editing.
* mail-text: Mail Mode Misc.
* mail-to: Header Editing.
* mail-yank-original: Citing Mail.
* mail-yank-region: Citing Mail.
* make-frame-command: Creating Frames.
* make-frame-on-display: Multiple Displays.
* make-indirect-buffer: Indirect Buffers.
* make-local-variable: Locals.
* make-symbolic-link: Misc File Ops.
* make-variable-buffer-local: Locals.
* Man-fontify-manpage: Documentation.
* manual-entry: Documentation.
* mark-calendar-holidays: Holidays.
* mark-defun: Defuns.
* mark-diary-entries: Diary Commands.
* mark-fortran-subprogram: Fortran Motion.
* mark-page: Pages.
* mark-paragraph: Paragraphs.
* mark-sexp: List Commands.
* mark-whole-buffer: Marking Objects.
* mark-word: Words.
* minibuffer-complete: Completion Example.
* minibuffer-complete-word: Completion Commands.
* mode25: MS-DOS Display.
* mode4350: MS-DOS Display.
* modify-face: Face Customization.
* mouse-choose-completion: Completion Commands.
* mouse-save-then-click: Mouse Commands.
* mouse-secondary-save-then-kill: Secondary Selection.
* mouse-set-point: Mouse Commands.
* mouse-set-region: Mouse Commands.
* mouse-set-secondary: Secondary Selection.
* mouse-start-secondary: Secondary Selection.
* mouse-yank-at-click: Mouse Commands.
* mouse-yank-secondary: Secondary Selection.
* move-past-close-and-reindent: Balanced Editing.
* move-to-window-line: Moving Point.
* mpuz: Amusements.
* name-last-kbd-macro: Save Kbd Macro.
* narrow-to-defun: Narrowing.
* narrow-to-page: Narrowing.
* narrow-to-region: Narrowing.
* negative-argument: Arguments.
* newline: Inserting Text.
* newline-and-indent: Basic Indent.
* next-completion: Completion Commands.
* next-error: Compilation Mode.
* next-history-element: Minibuffer History.
* next-line: Moving Point.
* next-matching-history-element: Minibuffer History.
* normal-mode: Choosing Modes.
* not-modified: Saving.
* nroff-mode: Nroff Mode.
* number-to-register: RegNumbers.
* occur: Other Repeating Search.
* open-dribble-file: Checklist.
* open-line: Blank Lines.
* open-rectangle: Rectangles.
* open-termscript: Checklist.
* other-frame: Misc X.
* other-window: Other Window.
* outline-backward-same-level: Outline Motion.
* outline-forward-same-level: Outline Motion.
* outline-minor-mode: Outline Mode.
* outline-mode: Outline Mode.
* outline-next-visible-heading: Outline Motion.
* outline-previous-visible-heading: Outline Motion.
* outline-up-heading: Outline Motion.
* overwrite-mode: Minor Modes.
* paragraph-indent-text-mode: Text Mode.
* pdb: Starting GUD.
* perldb: Starting GUD.
* phases-of-moon: Lunar Phases.
* picture-backward-clear-column: Basic Picture.
* picture-backward-column: Basic Picture.
* picture-clear-column: Basic Picture.
* picture-clear-line: Basic Picture.
* picture-clear-rectangle: Rectangles in Picture.
* picture-clear-rectangle-to-register: Rectangles in Picture.
* picture-forward-column: Basic Picture.
* picture-motion: Insert in Picture.
* picture-motion-reverse: Insert in Picture.
* picture-move-down: Basic Picture.
* picture-move-up: Basic Picture.
* picture-movement-down: Insert in Picture.
* picture-movement-left: Insert in Picture.
* picture-movement-ne: Insert in Picture.
* picture-movement-nw: Insert in Picture.
* picture-movement-right: Insert in Picture.
* picture-movement-se: Insert in Picture.
* picture-movement-sw: Insert in Picture.
* picture-movement-up: Insert in Picture.
* picture-newline: Basic Picture.
* picture-open-line: Basic Picture.
* picture-set-tab-stops: Tabs in Picture.
* picture-tab: Tabs in Picture.
* picture-tab-search: Tabs in Picture.
* picture-yank-rectangle: Rectangles in Picture.
* picture-yank-rectangle-from-register: Rectangles in Picture.
* plain-tex-mode: TeX Mode.
* point-to-register: RegPos.
* pop-global-mark: Global Mark Ring.
* pop-tag-mark: Find Tag.
* prefer-coding-system: Recognize Coding.
* prepend-to-buffer: Accumulating Text.
* previous-completion: Completion Commands.
* previous-history-element: Minibuffer History.
* previous-line: Moving Point.
* previous-matching-history-element: Minibuffer History.
* print-buffer: Hardcopy.
* print-buffer (MS-DOS): MS-DOS Printing.
* print-region: Hardcopy.
* print-region (MS-DOS): MS-DOS Printing.
* ps-print-buffer: Postscript.
* ps-print-buffer (MS-DOS): MS-DOS Printing.
* ps-print-buffer-with-faces: Postscript.
* ps-print-region: Postscript.
* ps-print-region-with-faces: Postscript.
* ps-spool-buffer: Postscript.
* ps-spool-buffer (MS-DOS): MS-DOS Printing.
* ps-spool-buffer-with-faces: Postscript.
* ps-spool-region: Postscript.
* ps-spool-region-with-faces: Postscript.
* pwd: File Names.
* quail-set-keyboard-layout: Select Input Method.
* query-replace: Query Replace.
* query-replace-regexp: Query Replace.
* quietly-read-abbrev-file: Saving Abbrevs.
* quoted-insert: Inserting Text.
* re-search-backward: Regexp Search.
* re-search-forward: Regexp Search.
* read-abbrev-file: Saving Abbrevs.
* recenter: Scrolling.
* recover-file: Recover.
* recover-session: Recover.
* redraw-calendar: General Calendar.
* remove-untranslated-filesystem: Text and Binary.
* rename-buffer: Misc Buffer.
* rename-file: Misc File Ops.
* repeat: Repeating.
* repeat-complex-command: Repetition.
* replace-regexp: Unconditional Replace.
* replace-string: Unconditional Replace.
* report-emacs-bug: Checklist.
* reposition-window: Scrolling.
* resize-minibuffer-mode: Minibuffer Edit.
* revert-buffer: Reverting.
* revert-buffer (Dired): Dired Updating.
* rlogin: Remote Host.
* rlogin-directory-tracking-mode: Remote Host.
* rmail: Rmail.
* rmail-add-label: Rmail Labels.
* rmail-beginning-of-message: Rmail Scrolling.
* rmail-bury: Rmail Basics.
* rmail-continue: Rmail Reply.
* rmail-delete-backward: Rmail Deletion.
* rmail-delete-forward: Rmail Deletion.
* rmail-edit-current-message: Rmail Editing.
* rmail-expunge: Rmail Deletion.
* rmail-first-message: Rmail Motion.
* rmail-forward: Rmail Reply.
* rmail-get-new-mail: Rmail Files.
* rmail-input: Rmail Files.
* rmail-kill-label: Rmail Labels.
* rmail-last-message: Rmail Motion.
* rmail-mail: Rmail Reply.
* rmail-mode: Rmail.
* rmail-next-labeled-message: Rmail Labels.
* rmail-next-message: Rmail Motion.
* rmail-next-undeleted-message: Rmail Motion.
* rmail-output: Rmail Output.
* rmail-output-body-to-file: Rmail Output.
* rmail-output-to-rmail-file: Rmail Output.
* rmail-previous-labeled-message: Rmail Labels.
* rmail-previous-message: Rmail Motion.
* rmail-previous-undeleted-message: Rmail Motion.
* rmail-quit: Rmail Basics.
* rmail-reply: Rmail Reply.
* rmail-resend: Rmail Reply.
* rmail-retry-failure: Rmail Reply.
* rmail-save: Rmail Basics.
* rmail-search: Rmail Motion.
* rmail-show-message: Rmail Motion.
* rmail-summary: Rmail Make Summary.
* rmail-summary-by-labels: Rmail Make Summary.
* rmail-summary-by-recipients: Rmail Make Summary.
* rmail-summary-by-topic: Rmail Make Summary.
* rmail-summary-quit: Rmail Summary Edit.
* rmail-summary-wipe: Rmail Summary Edit.
* rmail-toggle-header: Rmail Display.
* rmail-undelete-previous-message: Rmail Deletion.
* rot13-other-window: Rmail Rot13.
* run-lisp: External Lisp.
* save-buffer: Saving.
* save-buffers-kill-emacs: Exiting.
* save-some-buffers: Saving.
* scroll-bar-mode: Scroll Bars.
* scroll-calendar-left: Scroll Calendar.
* scroll-calendar-left-three-months: Scroll Calendar.
* scroll-calendar-right: Scroll Calendar.
* scroll-calendar-right-three-months: Scroll Calendar.
* scroll-down: Scrolling.
* scroll-left: Horizontal Scrolling.
* scroll-other-window: Other Window.
* scroll-right: Horizontal Scrolling.
* scroll-up: Scrolling.
* sdb: Starting GUD.
* search-backward: Nonincremental Search.
* search-forward: Nonincremental Search.
* select-frame-by-name: Non-Window Terminals.
* self-insert: Inserting Text.
* send-invisible: Shell Mode.
* server-edit: Emacs Server.
* set-background-color: Frame Parameters.
* set-border-color: Frame Parameters.
* set-buffer-file-coding-system: Specify Coding.
* set-buffer-process-coding-system: Specify Coding.
* set-comment-column: Options for Comments.
* set-cursor-color: Frame Parameters.
* set-fill-column: Fill Commands.
* set-fill-prefix: Fill Prefix.
* set-foreground-color: Frame Parameters.
* set-frame-font: Frame Parameters.
* set-frame-name: Non-Window Terminals.
* set-goal-column: Moving Point.
* set-input-method: Select Input Method.
* set-justification-center: Format Justification.
* set-justification-full: Format Justification.
* set-justification-left: Format Justification.
* set-justification-none: Format Justification.
* set-justification-right: Format Justification.
* set-keyboard-coding-system: Specify Coding.
* set-language-environment: Language Environments.
* set-mark-command: Setting Mark.
* set-mouse-color: Frame Parameters.
* set-next-selection-coding-system: Specify Coding.
* set-rmail-inbox-list: Rmail Files.
* set-selection-coding-system: Specify Coding.
* set-selective-display: Selective Display.
* set-terminal-coding-system: Specify Coding.
* set-variable: Examining.
* set-visited-file-name: Saving.
* setq-default: Locals.
* shell: Interactive Shell.
* shell-backward-command: Shell Mode.
* shell-command: Single Shell.
* shell-command-on-region: Single Shell.
* shell-forward-command: Shell Mode.
* shell-pushd-dextract: Shell Options.
* shell-pushd-dunique: Shell Options.
* shell-pushd-tohome: Shell Options.
* show-all: Outline Visibility.
* show-all-diary-entries: Diary Commands.
* show-branches: Outline Visibility.
* show-children: Outline Visibility.
* show-entry: Outline Visibility.
* show-paren-mode: Matching.
* show-subtree: Outline Visibility.
* shrink-window-if-larger-than-buffer: Change Window.
* slitex-mode: TeX Mode.
* sort-columns: Sorting.
* sort-fields: Sorting.
* sort-lines: Sorting.
* sort-numeric-fields: Sorting.
* sort-pages: Sorting.
* sort-paragraphs: Sorting.
* split-line: Indentation Commands.
* split-window-horizontally: Split Window.
* split-window-vertically: Split Window.
* spook: Distracting NSA.
* standard-display-8bit: Single-Byte European Support.
* start-kbd-macro: Basic Kbd Macro.
* string-rectangle: Rectangles.
* substitute-in-file-name: File Names.
* substitute-key-definition: Init Rebinding.
* sunrise-sunset: Sunrise/Sunset.
* suspend-emacs: Exiting.
* switch-to-buffer: Select Buffer.
* switch-to-buffer-other-frame: Select Buffer.
* switch-to-buffer-other-window: Select Buffer.
* switch-to-completions: Completion Commands.
* tab-to-tab-stop: Tab Stops.
* tabify: Just Spaces.
* tags-apropos: List Tags.
* tags-loop-continue: Tags Search.
* tags-query-replace: Tags Search.
* tags-search: Tags Search.
* telnet: Remote Host.
* tex-bibtex-file: TeX Print.
* tex-buffer: TeX Print.
* tex-close-latex-block: LaTeX Editing.
* tex-file: TeX Print.
* tex-insert-braces: TeX Editing.
* tex-insert-quote: TeX Editing.
* tex-kill-job: TeX Print.
* tex-latex-block: LaTeX Editing.
* tex-mode: TeX Mode.
* tex-print: TeX Print.
* tex-recenter-output-buffer: TeX Print.
* tex-region: TeX Print.
* tex-show-print-queue: TeX Print.
* tex-terminate-paragraph: TeX Editing.
* tex-validate-region: TeX Editing.
* tex-view: TeX Print.
* text-mode: Text Mode.
* tmm-menubar: Menu Bar.
* toggle-input-method: Select Input Method.
* toggle-scroll-bar: Scroll Bars.
* top-level: Quitting.
* transient-mark-mode: Transient Mark.
* transpose-chars: Transpose.
* transpose-lines: Transpose.
* transpose-sexps <1>: List Commands.
* transpose-sexps: Transpose.
* transpose-words <1>: Words.
* transpose-words: Transpose.
* turn-on-font-lock: Font Lock.
* undigestify-rmail-message: Rmail Digest.
* undo: Undo.
* unexpand-abbrev: Expanding Abbrevs.
* unforward-rmail-message: Rmail Reply.
* universal-argument: Arguments.
* universal-coding-system-argument: Specify Coding.
* unrmail: Out of Rmail.
* untabify: Just Spaces.
* up-list: TeX Editing.
* upcase-region: Case.
* upcase-word: Case.
* vc-annotate: Old Versions.
* vc-cancel-version: VC Undo.
* vc-create-snapshot: Making Snapshots.
* vc-diff: Old Versions.
* vc-directory: VC Dired Mode.
* vc-dired-mark-locked: VC Dired Commands.
* vc-dired-toggle-terse-mode: VC Dired Commands.
* vc-insert-headers: Version Headers.
* vc-merge: Merging.
* vc-next-action: Basic VC Editing.
* vc-print-log: VC Status.
* vc-register: Registering.
* vc-rename-file: Renaming and VC.
* vc-retrieve-snapshot: Making Snapshots.
* vc-revert-buffer: VC Undo.
* vc-toggle-read-only <1>: Misc Buffer.
* vc-toggle-read-only: Basic VC Editing.
* vc-update-change-log: Change Logs and VC.
* vc-version-other-window: Old Versions.
* vi-mode: Emulation.
* view-buffer: Misc Buffer.
* view-diary-entries: Diary Commands.
* view-emacs-FAQ: Misc Help.
* view-emacs-news: Misc Help.
* view-file: Misc File Ops.
* view-hello-file: International Intro.
* view-lossage: Misc Help.
* view-register: Registers.
* vip-mode: Emulation.
* viper-mode: Emulation.
* visit-tags-table: Select Tags Table.
* what-cursor-position: Position Info.
* what-line: Position Info.
* what-page: Position Info.
* where-is: Name Help.
* which-function-mode: Which Function.
* widen: Narrowing.
* widget-backward: Changing an Option.
* widget-complete: Changing an Option.
* widget-forward: Changing an Option.
* window-configuration-to-register: RegConfig.
* word-search-backward: Word Search.
* word-search-forward: Word Search.
* write-abbrev-file: Saving Abbrevs.
* write-file: Saving.
* write-region: Misc File Ops.
* xdb: Starting GUD.
* yank: Kill Ring.
* yank-pop: Earlier Kills.
* yank-rectangle: Rectangles.
* yow: Amusements.
* zap-to-char: Other Kill Commands.
Variable Index
**************
* Menu:
* abbrev-all-caps: Expanding Abbrevs.
* abbrev-file-name: Saving Abbrevs.
* abbrev-mode: Abbrev Concepts.
* adaptive-fill-first-line-regexp: Adaptive Fill.
* adaptive-fill-function: Adaptive Fill.
* adaptive-fill-mode: Adaptive Fill.
* adaptive-fill-regexp: Adaptive Fill.
* ange-ftp-default-user: Remote Files.
* appt-display-diary: Appointments.
* appt-issue-message: Appointments.
* apropos-do-all: Apropos.
* auto-coding-alist: Recognize Coding.
* auto-mode-alist: Choosing Modes.
* auto-save-default: Auto Save Control.
* auto-save-interval: Auto Save Control.
* auto-save-list-file-prefix: Recover.
* auto-save-timeout: Auto Save Control.
* auto-save-visited-file-name: Auto Save Files.
* backup-by-copying: Backup Copying.
* backup-by-copying-when-linked: Backup Copying.
* backup-by-copying-when-mismatch: Backup Copying.
* backup-enable-predicate: Backup.
* baud-rate: Display Vars.
* blink-matching-delay: Matching.
* blink-matching-paren: Matching.
* blink-matching-paren-distance: Matching.
* bookmark-save-flag: Bookmarks.
* bookmark-search-size: Bookmarks.
* buffer-file-coding-system: Recognize Coding.
* buffer-read-only: Misc Buffer.
* c-basic-offset: Variables for C Indent.
* c-comment-only-line-offset: Comments in C.
* c-comment-start-regexp: Comments in C.
* c-default-style: C Indent Styles.
* c-hanging-comment-ender-p: Comments in C.
* c-hanging-comment-starter-p: Comments in C.
* c-hungry-delete-key: Hungry Delete.
* c-mode-hook: Program Modes.
* c-mode-map: Local Keymaps.
* c-offsets-alist: Variables for C Indent.
* c-special-indent-hook: Variables for C Indent.
* c-strict-syntax-p: Indentation Calculation.
* c-style-alist: Variables for C Indent.
* c-syntactic-context: Syntactic Analysis.
* calendar-daylight-savings-ends: Daylight Savings.
* calendar-daylight-savings-ends-time: Daylight Savings.
* calendar-daylight-savings-starts: Daylight Savings.
* calendar-daylight-time-offset: Daylight Savings.
* calendar-daylight-time-zone-name: Sunrise/Sunset.
* calendar-latitude: Sunrise/Sunset.
* calendar-location-name: Sunrise/Sunset.
* calendar-longitude: Sunrise/Sunset.
* calendar-standard-time-zone-name: Sunrise/Sunset.
* calendar-time-zone: Sunrise/Sunset.
* calendar-week-start-day: Move to Beginning or End.
* case-fold-search: Search Case.
* case-replace: Replacement and Case.
* change-major-mode-with-file-name: Choosing Modes.
* coding: Recognize Coding.
* colon-double-space: Fill Commands.
* comint-completion-addsuffix: Shell Options.
* comint-completion-autolist: Shell Options.
* comint-completion-fignore: Shell Mode.
* comint-completion-recexact: Shell Options.
* comint-input-autoexpand: History References.
* comint-input-ignoredups: Shell Options.
* comint-prompt-regexp: History References.
* comint-scroll-show-maximum-output: Shell Options.
* comint-scroll-to-bottom-on-input: Shell Options.
* comint-scroll-to-bottom-on-output: Shell Options.
* command-history: Repetition.
* command-line-args: Action Arguments.
* comment-column: Options for Comments.
* comment-end: Options for Comments.
* comment-indent-function: Options for Comments.
* comment-line-start: Fortran Comments.
* comment-line-start-skip: Fortran Comments.
* comment-multi-line: Options for Comments.
* comment-padding: Multi-Line Comments.
* comment-start: Options for Comments.
* comment-start-skip: Options for Comments.
* compare-ignore-case: Comparing Files.
* compilation-scroll-output: Compilation.
* compile-command: Compilation.
* completion-auto-help: Completion Options.
* completion-ignored-extensions: Completion Options.
* ctl-arrow: Display Vars.
* ctl-x-4-map: Prefix Keymaps.
* ctl-x-map: Prefix Keymaps.
* current-input-method: Select Input Method.
* dabbrev-abbrev-char-regexp: Dabbrev Customization.
* dabbrev-abbrev-skip-leading-regexp: Dabbrev Customization.
* dabbrev-case-fold-search: Dabbrev Customization.
* dabbrev-case-replace: Dabbrev Customization.
* dabbrev-check-all-buffers: Dynamic Abbrevs.
* dabbrev-limit: Dynamic Abbrevs.
* dbx-mode-hook: GUD Customization.
* default-buffer-file-coding-system: Specify Coding.
* default-directory: File Names.
* default-enable-multibyte-characters: Enabling Multibyte.
* default-input-method: Select Input Method.
* default-justification: Format Justification.
* default-major-mode: Choosing Modes.
* delete-auto-save-files: Auto Save Files.
* delete-old-versions: Backup Deletion.
* desktop-enable: Saving Emacs Sessions.
* desktop-files-not-to-save: Saving Emacs Sessions.
* diary-file: Format of Diary File.
* diary-hook: Appointments.
* diary-mail-days: Diary Commands.
* diff-switches: Comparing Files.
* dired-chown-program: Operating on Files.
* dired-copy-preserve-time: Operating on Files.
* dired-garbage-files-regexp: Flagging Many Files.
* dired-kept-versions: Flagging Many Files.
* dired-listing-switches: Dired Enter.
* dired-listing-switches (MS-DOS): MS-DOS Processes.
* display-time-24hr-format: Optional Mode Line.
* dos-codepage: MS-DOS and MULE.
* dos-display-scancodes: MS-DOS Input.
* dos-hyper-key: MS-DOS Input.
* dos-keypad-mode: MS-DOS Input.
* dos-printer: MS-DOS Printing.
* dos-ps-printer: MS-DOS Printing.
* dos-super-key: MS-DOS Input.
* dos-unsupported-character-glyph: MS-DOS and MULE.
* double-click-time: Mouse Buttons.
* echo-keystrokes: Display Vars.
* emacs-lisp-mode-hook: Program Modes.
* emerge-combine-versions-template: Combining in Emerge.
* emerge-startup-hook: Fine Points of Emerge.
* enable-multibyte-characters <1>: Single-Byte European Support.
* enable-multibyte-characters: Enabling Multibyte.
* enable-recursive-minibuffers: Minibuffer Edit.
* enriched-fill-after-visiting: Requesting Formatted Text.
* enriched-translations: Requesting Formatted Text.
* eol-mnemonic-dos: Mode Line.
* eol-mnemonic-mac: Mode Line.
* eol-mnemonic-undecided: Mode Line.
* eol-mnemonic-unix: Mode Line.
* esc-map: Prefix Keymaps.
* european-calendar-style: Date Formats.
* exit-language-environment-hook: Language Environments.
* explicit-shell-file-name: Interactive Shell.
* fast-lock-cache-directories: Fast Lock Mode.
* fast-lock-minimum-size: Fast Lock Mode.
* fast-lock-save-others: Fast Lock Mode.
* file-coding-system-alist: Recognize Coding.
* file-name-buffer-file-type-alist: Text and Binary.
* file-name-coding-system: Specify Coding.
* file-name-handler-alist: Remote Files.
* fill-column: Fill Commands.
* fill-prefix: Fill Prefix.
* find-file-existing-other-name: File Aliases.
* find-file-hooks: Visiting.
* find-file-not-found-hooks: Visiting.
* find-file-run-dired: Visiting.
* find-file-visit-truename: File Aliases.
* find-ls-option: Dired and Find.
* find-tag-marker-ring-length: Find Tag.
* font-lock-beginning-of-syntax-function: Font Lock.
* font-lock-mark-block-function: Font Lock.
* font-lock-maximum-decoration: Font Lock.
* font-lock-maximum-size: Font Lock.
* font-lock-support-mode: Fast or Lazy.
* fortran-analyze-depth: ForIndent Cont.
* fortran-break-before-delimiters: Fortran Autofill.
* fortran-check-all-num...: ForIndent Vars.
* fortran-column-ruler: Fortran Columns.
* fortran-comment-indent-char: Fortran Comments.
* fortran-comment-indent-style: Fortran Comments.
* fortran-comment-line-extra-indent: Fortran Comments.
* fortran-comment-region: Fortran Comments.
* fortran-continuation-indent: ForIndent Vars.
* fortran-continuation-string: ForIndent Cont.
* fortran-do-indent: ForIndent Vars.
* fortran-electric-line-number: ForIndent Num.
* fortran-if-indent: ForIndent Vars.
* fortran-line-number-indent: ForIndent Num.
* fortran-minimum-statement-indent...: ForIndent Vars.
* fortran-structure-indent: ForIndent Vars.
* fortran-tab-mode-default: ForIndent Cont.
* gdb-mode-hook: GUD Customization.
* gud-xdb-directories: Starting GUD.
* help-map: Prefix Keymaps.
* highlight-nonselected-windows: Transient Mark.
* highlight-wrong-size-font: Fontsets.
* history-length: Minibuffer History.
* indent-tabs-mode: Just Spaces.
* indent-tabs-mode (Fortran mode): ForIndent Cont.
* inferior-lisp-program: External Lisp.
* inhibit-eol-conversion: Recognize Coding.
* initial-major-mode: Entering Emacs.
* input-method-highlight-flag: Input Methods.
* input-method-verbose-flag: Input Methods.
* insert-default-directory: File Names.
* interpreter-mode-alist: Choosing Modes.
* inverse-video: Display Vars.
* isearch-mode-map: Incremental Search.
* ispell-dictionary: Spelling.
* jdb-mode-hook: GUD Customization.
* kept-new-versions: Backup Deletion.
* kept-old-versions: Backup Deletion.
* kill-buffer-hook: Kill Buffer.
* kill-ring: Earlier Kills.
* kill-ring-max: Earlier Kills.
* kill-whole-line: Killing by Lines.
* latex-block-names: LaTeX Editing.
* latex-mode-hook: TeX Print.
* latex-run-command: TeX Print.
* lazy-lock-defer-contextually: Lazy Lock Mode.
* lazy-lock-defer-on-scrolling: Lazy Lock Mode.
* lazy-lock-defer-time: Lazy Lock Mode.
* lazy-lock-minimum-size: Lazy Lock Mode.
* lazy-lock-stealth-lines: Lazy Lock Mode.
* lazy-lock-stealth-time: Lazy Lock Mode.
* lazy-lock-stealth-verbose: Lazy Lock Mode.
* line-number-display-limit: Optional Mode Line.
* lisp-body-indent: Lisp Indent.
* lisp-indent-offset: Lisp Indent.
* lisp-interaction-mode-hook: Program Modes.
* lisp-mode-hook: Program Modes.
* lisp-mode-map: Local Keymaps.
* list-directory-brief-switches: Directories.
* list-directory-verbose-switches: Directories.
* load-path: Lisp Libraries.
* lpr-add-switches: Hardcopy.
* lpr-command (MS-DOS): MS-DOS Printing.
* lpr-commands: Hardcopy.
* lpr-headers-switches: Hardcopy.
* lpr-headers-switches (MS-DOS): MS-DOS Printing.
* lpr-switches: Hardcopy.
* lpr-switches (MS-DOS): MS-DOS Printing.
* mail-abbrevs: Mail Aliases.
* mail-aliases: Mail Aliases.
* mail-archive-file-name: Mail Headers.
* mail-default-reply-to: Mail Headers.
* mail-from-style: Mail Headers.
* mail-mode-hook: Mail Mode Misc.
* mail-personal-alias-file: Mail Aliases.
* mail-self-blind: Mail Headers.
* mail-setup-hook: Mail Mode Misc.
* mail-signature: Mail Mode Misc.
* mail-user-agent: Mail Methods.
* mail-yank-prefix: Citing Mail.
* make-backup-files: Backup.
* Man-fontify-manpage-flag: Documentation.
* mark-even-if-inactive: Transient Mark.
* mark-ring: Mark Ring.
* mark-ring-max: Mark Ring.
* message-log-max: Echo Area.
* midnight-hook: Kill Buffer.
* midnight-mode: Kill Buffer.
* minibuffer-local-completion-map: Minibuffer Maps.
* minibuffer-local-map: Minibuffer Maps.
* minibuffer-local-must-match-map: Minibuffer Maps.
* minibuffer-local-ns-map: Minibuffer Maps.
* minibuffer-scroll-overlap: Minibuffer Edit.
* mode-line-inverse-video: Display Vars.
* mode-specific-map: Prefix Keymaps.
* mouse-scroll-min-lines: Mouse Commands.
* mouse-yank-at-point: Mouse Commands.
* muddle-mode-hook: Program Modes.
* next-line-add-newlines: Moving Point.
* next-screen-context-lines: Scrolling.
* no-redraw-on-reenter: Display Vars.
* nroff-mode-hook: Nroff Mode.
* outline-level: Outline Format.
* outline-minor-mode-prefix: Outline Mode.
* outline-mode-hook: Outline Mode.
* outline-regexp: Outline Format.
* page-delimiter: Pages.
* paragraph-separate: Paragraphs.
* paragraph-start: Paragraphs.
* parens-require-spaces: Balanced Editing.
* pdb-mode-hook: GUD Customization.
* perldb-mode-hook: GUD Customization.
* picture-mode-hook: Picture.
* picture-tab-chars: Tabs in Picture.
* plain-tex-mode-hook: TeX Print.
* print-region-function (MS-DOS): MS-DOS Printing.
* printer-name: Hardcopy.
* printer-name (MS-DOS): MS-DOS Printing.
* ps-font-family: Postscript Variables.
* ps-font-info-database: Postscript Variables.
* ps-font-size: Postscript Variables.
* ps-landscape-mode: Postscript Variables.
* ps-lpr-command: Postscript Variables.
* ps-lpr-command (MS-DOS): MS-DOS Printing.
* ps-lpr-switches: Postscript Variables.
* ps-lpr-switches (MS-DOS): MS-DOS Printing.
* ps-number-of-columns: Postscript Variables.
* ps-page-dimensions-database: Postscript Variables.
* ps-paper-type: Postscript Variables.
* ps-print-color-p: Postscript Variables.
* ps-print-header: Postscript Variables.
* ps-printer-name: Postscript Variables.
* ps-printer-name (MS-DOS): MS-DOS Printing.
* read-quoted-char-radix: Inserting Text.
* require-final-newline: Saving.
* revert-without-query: Reverting.
* rlogin-explicit-args: Remote Host.
* rmail-decode-mime-charset: Recognize Coding.
* rmail-delete-after-output: Rmail Output.
* rmail-delete-message-hook: Rmail Deletion.
* rmail-dont-reply-to-names: Rmail Reply.
* rmail-edit-mode-hook: Rmail Editing.
* rmail-file-coding-system: Recognize Coding.
* rmail-file-name: Rmail Basics.
* rmail-highlighted-headers: Rmail Display.
* rmail-ignored-headers: Rmail Display.
* rmail-mail-new-frame: Rmail Reply.
* rmail-mode-hook: Rmail.
* rmail-movemail-flags: Movemail.
* rmail-output-file-alist: Rmail Output.
* rmail-pop-password: Movemail.
* rmail-pop-password-required: Movemail.
* rmail-preserve-inbox: Movemail.
* rmail-primary-inbox-list: Rmail Inbox.
* rmail-redisplay-summary: Rmail Summary Edit.
* rmail-retry-ignored-headers: Rmail Reply.
* rmail-secondary-file-directory: Rmail Files.
* rmail-secondary-file-regexp: Rmail Files.
* rmail-summary-line-count-flag: Rmail Make Summary.
* rmail-summary-window-size: Rmail Make Summary.
* same-window-buffer-names: Force Same Window.
* same-window-regexps: Force Same Window.
* save-abbrevs: Saving Abbrevs.
* scheme-mode-hook: Program Modes.
* scroll-conservatively: Scrolling.
* scroll-margin: Scrolling.
* scroll-preserve-screen-position: Scrolling.
* sdb-mode-hook: GUD Customization.
* search-slow-speed: Incremental Search.
* search-slow-window-lines: Incremental Search.
* selective-display-ellipses: Selective Display.
* sendmail-coding-system <1>: Mail Sending.
* sendmail-coding-system: Recognize Coding.
* sentence-end: Sentences.
* sentence-end-double-space: Fill Commands.
* server-temp-file-regexp: Emacs Server.
* server-window: Emacs Server.
* set-language-environment-hook: Language Environments.
* shell-cd-regexp: Interactive Shell.
* shell-command-default-error-buffer: Single Shell.
* shell-command-execonly: Shell Options.
* shell-command-regexp: Shell Mode.
* shell-completion-fignore: Shell Mode.
* shell-file-name: Single Shell.
* shell-input-ring-file-name: Shell Ring.
* shell-popd-regexp: Interactive Shell.
* shell-prompt-pattern: History References.
* shell-pushd-regexp: Interactive Shell.
* shell-set-directory-error-hook: Interactive Shell.
* slitex-mode-hook: TeX Print.
* slitex-run-command: TeX Print.
* sort-fold-case: Sorting.
* special-display-buffer-names: Special Buffer Frames.
* special-display-frame-alist: Special Buffer Frames.
* special-display-regexps: Special Buffer Frames.
* split-window-keep-point: Split Window.
* standard-fontset-spec: Defining Fontsets.
* standard-indent: Format Indentation.
* suggest-key-bindings: M-x.
* tab-stop-list: Tab Stops.
* tab-width: Display Vars.
* tags-file-name: Select Tags Table.
* tags-table-list: Select Tags Table.
* term-file-prefix: Terminal Init.
* term-setup-hook: Terminal Init.
* tex-bibtex-command: TeX Print.
* tex-default-mode: TeX Mode.
* tex-directory: TeX Print.
* tex-dvi-print-command: TeX Print.
* tex-dvi-view-command: TeX Print.
* tex-main-file: TeX Print.
* tex-mode-hook: TeX Print.
* tex-run-command: TeX Print.
* tex-shell-hook: TeX Print.
* tex-show-queue-command: TeX Print.
* tex-start-options-string: TeX Print.
* text-mode-hook: Text Mode.
* track-eol: Moving Point.
* truncate-lines: Continuation Lines.
* truncate-partial-width-windows: Split Window.
* undo-limit: Undo.
* undo-strong-limit: Undo.
* unibyte-display-via-language-environment: Single-Byte European Support.
* user-mail-address: Init Examples.
* vc-command-messages: VC Command Execution.
* vc-comment-alist: Version Headers.
* vc-consult-headers: VC Status Retrieval.
* vc-default-back-end: Registering.
* vc-default-init-version: Registering.
* vc-directory-exclusion-list: VC Dired Mode.
* vc-dired-recurse: VC Dired Mode.
* vc-dired-terse-display: VC Dired Mode.
* vc-follow-symlinks: VC Workfile Handling.
* vc-handle-cvs: Backend Options.
* vc-header-alist: Version Headers.
* vc-initial-comment: Registering.
* vc-keep-workfiles: VC Workfile Handling.
* vc-log-mode-hook: Log Buffer.
* vc-make-backup-files <1>: VC Workfile Handling.
* vc-make-backup-files: Backup.
* vc-mistrust-permissions: VC Status Retrieval.
* vc-path: VC Command Execution.
* vc-static-header-alist: Version Headers.
* vc-suppress-confirm: VC Command Execution.
* version-control: Backup Names.
* visible-bell: Display Vars.
* w32-pass-alt-to-system: Windows System Menu.
* which-func-modes: Which Function.
* window-min-height: Change Window.
* window-min-width: Change Window.
* x-cut-buffer-max: Mouse Commands.
* xdb-mode-hook: GUD Customization.
Concept Index
*************
* Menu:
* *Messages* buffer: Echo Area.
* .mailrc file: Mail Aliases.
* // in file name: Minibuffer File.
* 8-bit display: Single-Byte European Support.
* <ESC> replacing <META> key: User Input.
* A and B buffers (Emerge): Overview of Emerge.
* Abbrev mode: Abbrev Concepts.
* abbrevs: Abbrevs.
* aborting recursive edit: Quitting.
* accented characters: Single-Byte European Support.
* accessible portion: Narrowing.
* accumulating scattered text: Accumulating Text.
* action options (command line): Command Arguments.
* active fields (customization buffer): Customization Groups.
* adaptive filling: Adaptive Fill.
* againformation: Dissociated Press.
* alarm clock: Appointments.
* ange-ftp: Remote Files.
* appending kills in the ring: Appending Kills.
* appointment notification: Appointments.
* apropos: Apropos.
* arguments (command line): Command Arguments.
* arguments, numeric: Arguments.
* arguments, prefix: Arguments.
* arrow keys: Moving Point.
* ASCII: User Input.
* Asm mode: Asm Mode.
* astronomical day numbers: Calendar Systems.
* attribute (Rmail): Rmail Labels.
* Auto Compression mode: Compressed Files.
* Auto Fill mode: Auto Fill.
* Auto Save mode: Auto Save.
* Auto-Lower mode: Frame Parameters.
* Auto-Raise mode: Frame Parameters.
* autoload: Lisp Libraries.
* Awk mode: Program Modes.
* back end (version control): Version Systems.
* backend options (VC): Backend Options.
* backtrace for bug reports: Checklist.
* backup file: Backup.
* backup file names on MS-DOS: MS-DOS File Names.
* base buffer: Indirect Buffers.
* batch mode: Initial Options.
* binding: Commands.
* blank lines: Blank Lines.
* blank lines in programs: Multi-Line Comments.
* body lines (Outline mode): Outline Format.
* bold font: Face Customization.
* bookmarks: Bookmarks.
* borders (X Windows): Borders X.
* boredom: Amusements.
* branch (version control): Branches.
* buffer menu: Several Buffers.
* buffers: Buffers.
* buggestion: Dissociated Press.
* bugs: Bugs.
* building programs: Building.
* button down events: Mouse Buttons.
* byte code: Lisp Libraries.
* C editing: Programs.
* c indentation styles: C Indent Styles.
* C mode: C Modes.
* C++ mode: C Modes.
* C-: User Input.
* calendar: Calendar/Diary.
* calendar and LaTeX: LaTeX Calendar.
* calendar, first day of week: Move to Beginning or End.
* capitalizing words: Case.
* case conversion: Case.
* centering: Fill Commands.
* change buffers: Select Buffer.
* change log: Change Log.
* Change Log mode: Change Log.
* changes, undoing: Undo.
* character set (keyboard): User Input.
* characters (in text) <1>: Text Display.
* characters (in text): Text Characters.
* checking out files: VC Concepts.
* checking spelling: Spelling.
* Chinese: International.
* Chinese calendar: Calendar Systems.
* choosing a major mode: Choosing Modes.
* citing mail: Citing Mail.
* click events: Mouse Buttons.
* codepage, MS-DOS: MS-DOS and MULE.
* coding systems: Coding Systems.
* collision: Interlocking.
* color of window (X Windows): Colors X.
* colors: Frame Parameters.
* Column Number mode: Optional Mode Line.
* columns (and rectangles): Rectangles.
* columns (indentation): Indentation.
* columns, splitting: Two-Column.
* Comint mode: Shell Mode.
* command: Commands.
* command history: Repetition.
* command line arguments: Command Arguments.
* comments: Comments.
* comparing files: Comparing Files.
* compilation errors: Compilation.
* Compilation mode: Compilation Mode.
* compilation under MS-DOS: MS-DOS Processes.
* complete: Completion Options.
* complete key: Keys.
* completion: Completion.
* completion (symbol names): Symbol Completion.
* completion in Lisp: Symbol Completion.
* completion using tags: Symbol Completion.
* compression: Compressed Files.
* conflicts: Merging.
* connecting to remote host: Remote Host.
* continuation line: Continuation Lines.
* Control: User Input.
* control characters: User Input.
* Control-Meta: Lists.
* converting text to upper or lower case: Case.
* Coptic calendar: Calendar Systems.
* copying files: Misc File Ops.
* copying text: Yanking.
* CORBA IDL mode: C Modes.
* correcting spelling: Spelling.
* CPerl mode: Program Modes.
* crashes: Auto Save.
* creating files: Visiting.
* creating frames: Creating Frames.
* current buffer: Buffers.
* cursor: Point.
* cursor location: Position Info.
* cursor location, under MS-DOS: Text and Binary.
* cursor motion: Moving Point.
* customization: Customization.
* customization buffer: Easy Customization.
* customization groups: Customization Groups.
* customizing faces: Face Customization.
* customizing Lisp indentation: Lisp Indent.
* cut buffer: Mouse Commands.
* cutting and X: Mouse Commands.
* cutting text: Killing.
* CVS: Version Systems.
* cvs watch feature: Backend Options.
* CVSREAD environment variable (CVS): Backend Options.
* day of year: General Calendar.
* daylight savings time: Daylight Savings.
* DBX: Debuggers.
* debuggers: Debuggers.
* default argument: Minibuffer.
* default-frame-alist: Creating Frames.
* defining keyboard macros: Keyboard Macros.
* defuns: Defuns.
* deleting blank lines: Blank Lines.
* deleting characters and lines: Erasing.
* deleting files (in Dired): Dired Deletion.
* deletion: Killing.
* deletion (of files): Misc File Ops.
* deletion (Rmail): Rmail Deletion.
* desktop: Saving Emacs Sessions.
* Devanagari: International.
* developediment: Dissociated Press.
* diary: Diary.
* diary file: Format of Diary File.
* digest message: Rmail Digest.
* directory header lines: Subdirectory Motion.
* directory listing: Directories.
* directory listing on MS-DOS: MS-DOS Processes.
* Dired: Dired.
* Dired sorting: Dired Updating.
* disabled command: Disabling.
* DISPLAY environment variable: Display X.
* display name (X Windows): Display X.
* doctor: Total Frustration.
* DOS codepages: MS-DOS and MULE.
* double clicks: Mouse Buttons.
* double slash in file name: Minibuffer File.
* down events: Mouse Buttons.
* drag events: Mouse Buttons.
* drastic changes: Reverting.
* dribble file: Checklist.
* echo area: Echo Area.
* editable fields (customization buffer): Customization Groups.
* editing binary files: Editing Binary Files.
* editing in Picture mode: Basic Picture.
* editing level, recursive: Recursive Edit.
* EDITOR environment variable: Emacs Server.
* EDT: Emulation.
* Eldoc mode: Documentation.
* Eliza: Total Frustration.
* Emacs as a server: Emacs Server.
* Emacs initialization file: Init File.
* Emacs-Lisp mode: Lisp Eval.
* emacsclient: Emacs Server.
* Emerge: Emerge.
* emulating other editors: Emulation.
* encoding of characters: International.
* end-of-line conversion: Coding Systems.
* end-of-line conversion on MS-DOS/MS-Windows: Text and Binary.
* end-of-line conversion, mode-line indication: Mode Line.
* Enriched mode: Formatted Text.
* entering Emacs: Entering Emacs.
* environment: Single Shell.
* environment variables: Environment.
* erasing characters and lines: Erasing.
* error log: Compilation.
* error message in the echo area: Echo Area.
* ESHELL environment variable: Interactive Shell.
* etags program: Create Tags Table.
* Ethiopian: International.
* Ethiopic calendar: Calendar Systems.
* European character sets: Single-Byte European Support.
* exiting: Exiting.
* exiting recursive edit: Recursive Edit.
* expanding subdirectories in Dired: Subdirectories in Dired.
* expansion (of abbrevs): Abbrevs.
* expansion of C macros: Other C Commands.
* expression: Lists.
* expunging (Dired): Dired Deletion.
* expunging (Rmail): Rmail Deletion.
* faces: Faces.
* faces under MS-DOS: MS-DOS Display.
* Fast Lock mode: Fast Lock Mode.
* file dates: Interlocking.
* file directory: Directories.
* file local variables: File Variables.
* file names: File Names.
* file names under MS-DOS: MS-DOS File Names.
* file names under Windows 95/NT: MS-DOS File Names.
* file truenames: File Aliases.
* files: Files.
* files, visiting and saving: Visiting.
* fill prefix: Fill Prefix.
* filling text: Filling.
* find and Dired: Dired and Find.
* finding strings within text: Search.
* flagging files (in Dired): Dired Deletion.
* flow control: Unasked-for Search.
* Flyspell mode: Spelling.
* Follow mode: Follow Mode.
* font (default): Creating Frames.
* font (principal): Frame Parameters.
* Font Lock mode: Font Lock.
* font name (X Windows): Font X.
* fonts and faces: Face Customization.
* fonts, emulating under MS-DOS: MS-DOS Display.
* fontsets: Fontsets.
* formatted text: Formatted Text.
* formfeed: Pages.
* Fortran continuation lines: ForIndent Cont.
* Fortran mode: Fortran.
* forwarding a message: Rmail Reply.
* frame size under MS-DOS: MS-DOS Display.
* frames: Frames.
* frames on MS-DOS: MS-DOS Display.
* French Revolutionary calendar: Calendar Systems.
* FTP: Remote Files.
* function: Commands.
* function definition: Commands.
* function key: Keymaps.
* GDB: Debuggers.
* geometry (X Windows): Window Size X.
* getting help with keys: Basic Help.
* global keymap: Keymaps.
* global mark ring: Global Mark Ring.
* global substitution: Replace.
* Gnus: Gnus.
* Go Moku: Amusements.
* graphic characters: Inserting Text.
* Greek: International.
* Gregorian calendar: Other Calendars.
* growing minibuffer: Minibuffer Edit.
* GUD library: Debuggers.
* gzip: Compressed Files.
* hard newline: Hard and Soft Newlines.
* hardcopy: Hardcopy.
* head version: Branches.
* header (TeX mode): TeX Print.
* header line (Dired): Subdirectory Motion.
* headers (of mail message): Mail Headers.
* heading lines (Outline mode): Outline Format.
* Hebrew calendar: Calendar Systems.
* height of minibuffer: Minibuffer Edit.
* help: Help.
* Hexl mode: Editing Binary Files.
* hiding in Dired (Dired): Hiding Subdirectories.
* highlighting region: Transient Mark.
* Hindi: International.
* history of commands: Repetition.
* history of minibuffer input: Minibuffer History.
* history reference: History References.
* holidays: Holidays.
* HOME directory under MS-DOS: MS-DOS File Names.
* hook: Hooks.
* horizontal scrolling: Horizontal Scrolling.
* Hscroll mode: Horizontal Scrolling.
* Hyper (under MS-DOS): MS-DOS Input.
* Icomplete mode: Completion Options.
* Icon mode: Program Modes.
* icons (X Windows): Icons X.
* IDL mode: C Modes.
* ignoriginal: Dissociated Press.
* in-situ subdirectory (Dired): Subdirectories in Dired.
* inbox file: Rmail Inbox.
* incremental search: Incremental Search.
* indentation: Indentation.
* Indentation Calculation: Indentation Calculation.
* indentation for comments: Comment Commands.
* indentation for programs: Program Indent.
* indirect buffer: Indirect Buffers.
* indirect buffers and outlines: Outline Views.
* inferior process: Compilation.
* inferior processes under MS-DOS: MS-DOS Processes.
* Info: Misc Help.
* Info index completion: Symbol Completion.
* init file: Init File.
* init file, default name under MS-DOS: MS-DOS File Names.
* initial options (command line): Command Arguments.
* initial-frame-alist: Creating Frames.
* input event: User Input.
* input methods: Input Methods.
* input with the keyboard: User Input.
* inserted subdirectory (Dired): Subdirectories in Dired.
* inserting blank lines: Blank Lines.
* insertion: Inserting Text.
* international scripts: International.
* international support (MS-DOS): MS-DOS and MULE.
* interval operator (in regexps): Create Tags Table.
* invisible lines: Outline Mode.
* IPA: International.
* Islamic calendar: Calendar Systems.
* ISO commercial calendar: Calendar Systems.
* ISO Latin character sets: Single-Byte European Support.
* iso-ascii library: Single-Byte European Support.
* iso-transl library: Single-Byte European Support.
* ispell program: Spelling.
* italic font: Face Customization.
* Japanese: International.
* Java mode: C Modes.
* JDB: Debuggers.
* Julian calendar: Calendar Systems.
* Julian day numbers: Calendar Systems.
* justification: Fill Commands.
* Kerberos POP authentication: Movemail.
* key: Keys.
* key bindings: Key Bindings.
* key rebinding, permanent: Init File.
* key rebinding, this session: Rebinding.
* key sequence: Keys.
* keyboard input: User Input.
* keyboard macro: Keyboard Macros.
* keyboard translations: Keyboard Translations.
* keymap: Keymaps.
* kill ring: Yanking.
* killing buffers: Kill Buffer.
* killing characters and lines: Erasing.
* killing Emacs: Exiting.
* killing rectangular areas of text: Rectangles.
* killing text: Killing.
* Korean: International.
* label (Rmail): Rmail Labels.
* language environment, automatic selection on MS-DOS: MS-DOS and MULE.
* language environments: Language Environments.
* Lao: International.
* LaTeX mode: TeX Mode.
* Lazy Lock mode: Lazy Lock Mode.
* leaving Emacs: Exiting.
* libraries: Lisp Libraries.
* line number commands: Position Info.
* Line Number mode: Optional Mode Line.
* line wrapping: Continuation Lines.
* Lisp editing: Programs.
* Lisp string syntax: Init Syntax.
* Lisp symbol completion: Symbol Completion.
* list: Lists.
* listing current buffers: List Buffers.
* loading Lisp code: Lisp Libraries.
* local keymap: Local Keymaps.
* local variables: Locals.
* local variables in files: File Variables.
* location of point: Position Info.
* locking (CVS): Backend Options.
* locking and version control: VC Concepts.
* locking files: Interlocking.
* locking under version control: Backend Options.
* locking, non-strict (RCS): Backend Options.
* long file names in DOS box under Windows 95/NT: MS-DOS File Names.
* lpr usage under MS-DOS: MS-DOS Printing.
* Lucid Widget X Resources: Lucid Resources.
* M-: User Input.
* Macintosh end-of-line conversion: Coding Systems.
* macro expansion in C: Other C Commands.
* mail: Sending Mail.
* mail (on mode line): Optional Mode Line.
* mail aliases: Mail Aliases.
* MAIL environment variable: Rmail Inbox.
* Mail mode: Mail Mode.
* mail-composition methods: Mail Methods.
* MAILHOST environment variable: Movemail.
* mailrc file: Mail Aliases.
* major modes: Major Modes.
* make: Compilation.
* Makefile mode: Program Modes.
* making pictures out of text characters: Picture.
* manipulating paragraphs: Paragraphs.
* manipulating sentences: Sentences.
* manipulating text: Text.
* manuals, on-line: Misc Help.
* Marathi: International.
* mark: Mark.
* mark ring: Mark Ring.
* marking in Dired: Marks vs Flags.
* marking sections of text: Marking Objects.
* Markov chain: Dissociated Press.
* master file: VC Concepts.
* matching parentheses: Matching.
* Mayan calendar: Calendar Systems.
* Mayan calendar round: Mayan Calendar.
* Mayan haab calendar: Mayan Calendar.
* Mayan long count: Mayan Calendar.
* Mayan tzolkin calendar: Mayan Calendar.
* memory full: Memory Full.
* menu bar: Menu Bar.
* Menu Bar mode: Menu Bars.
* Menu X Resources (Lucid widgets): Lucid Resources.
* Menu X Resources (Motif widgets): Motif Resources.
* merge buffer (Emerge): Overview of Emerge.
* merging changes: Merging.
* merging files: Emerge.
* message: Sending Mail.
* message number: Rmail Basics.
* messages saved from echo area: Echo Area.
* Meta: User Input.
* Meta (under MS-DOS): MS-DOS Input.
* Meta commands and words: Words.
* Midnight mode: Kill Buffer.
* minibuffer: Minibuffer.
* minibuffer history: Minibuffer History.
* minibuffer keymaps: Minibuffer Maps.
* minor mode keymap: Local Keymaps.
* minor modes: Minor Modes.
* mistakes, correcting: Fixit.
* mode hook: Program Modes.
* mode line: Mode Line.
* mode line (MS-DOS): MS-DOS and MULE.
* mode, Abbrev: Abbrev Concepts.
* mode, Auto Compression: Compressed Files.
* mode, Auto Fill: Auto Fill.
* mode, Auto Save: Auto Save.
* mode, C: C Modes.
* mode, Column Number: Optional Mode Line.
* mode, Comint: Shell Mode.
* mode, Compilation: Compilation Mode.
* mode, CORBA IDL: C Modes.
* mode, Emacs-Lisp: Lisp Eval.
* mode, Enriched: Formatted Text.
* mode, Fast Lock: Fast Lock Mode.
* mode, Follow: Follow Mode.
* mode, Font Lock: Font Lock.
* mode, Fortran: Fortran.
* mode, Hexl: Editing Binary Files.
* mode, Hscroll: Horizontal Scrolling.
* mode, Java: C Modes.
* mode, LaTeX: TeX Mode.
* mode, Lazy Lock: Lazy Lock Mode.
* mode, Line Number: Optional Mode Line.
* mode, Mail: Mail Mode.
* mode, major: Major Modes.
* mode, Menu Bar: Menu Bars.
* mode, minor: Minor Modes.
* mode, Objective C: C Modes.
* mode, Outline: Outline Mode.
* mode, Overwrite: Minor Modes.
* mode, Paragraph-Indent Text: Text Mode.
* mode, Pike: C Modes.
* mode, Resize-Minibuffer: Minibuffer Edit.
* mode, Scroll Bar: Scroll Bars.
* mode, Shell: Shell Mode.
* mode, SliTeX: TeX Mode.
* mode, TeX: TeX Mode.
* mode, Text: Text Mode.
* mode, Transient Mark: Transient Mark.
* mode, View: Misc File Ops.
* modes for programming languages: Program Modes.
* modified (buffer): Visiting.
* moon, phases of: Lunar Phases.
* Motif Widget X Resources: Motif Resources.
* mouse: Keymaps.
* mouse button events: Mouse Buttons.
* mouse buttons (what they do): Mouse Commands.
* mouse support under MS-DOS: MS-DOS Input.
* movemail: Movemail.
* movemail program: Movemail.
* movement: Moving Point.
* moving inside the calendar: Calendar Motion.
* moving point: Moving Point.
* moving text: Yanking.
* moving the cursor: Moving Point.
* MS-DOG: MS-DOS.
* MS-DOS end-of-line conversion: Coding Systems.
* MS-DOS peculiarities: MS-DOS.
* MULE: International.
* multibyte characters: International.
* multiple displays: Multiple Displays.
* multiple views of outline: Outline Views.
* multiple windows in Emacs: Windows.
* mustatement: Dissociated Press.
* named configurations (RCS): Snapshot Caveats.
* narrowing: Narrowing.
* newline: Inserting Text.
* newlines, hard and soft: Hard and Soft Newlines.
* NFS and quitting: Quitting.
* non-strict locking (RCS): Backend Options.
* non-window terminals: Non-Window Terminals.
* nonincremental search: Nonincremental Search.
* nroff: Nroff Mode.
* NSA: Distracting NSA.
* numeric arguments: Arguments.
* Objective C mode: C Modes.
* on-line manuals: Misc Help.
* operating on files in Dired: Operating on Files.
* operations on a marked region: Using Region.
* option, user: Variables.
* options (command line): Command Arguments.
* other editors: Emulation.
* out of memory: Memory Full.
* Outline mode: Outline Mode.
* outline with multiple views: Outline Views.
* outragedy: Dissociated Press.
* Overwrite mode: Minor Modes.
* pages: Pages.
* Paragraph-Indent Text mode: Text Mode.
* paragraphs: Paragraphs.
* parentheses: Matching.
* parts of the screen: Screen.
* pasting: Yanking.
* pasting and X: Mouse Commands.
* patches, sending: Sending Patches.
* PDB: Debuggers.
* per-buffer variables: Locals.
* Perl mode: Program Modes.
* Perldb: Debuggers.
* Persian calendar: Calendar Systems.
* phases of the moon: Lunar Phases.
* Picture mode and rectangles: Rectangles in Picture.
* pictures: Picture.
* Pike mode: C Modes.
* point: Point.
* point location: Position Info.
* point location, under MS-DOS: Text and Binary.
* POP inboxes: Movemail.
* POP inboxes in reverse order: Movemail.
* prefix arguments: Arguments.
* prefix key: Keys.
* preprocessor highlighting: Other C Commands.
* presidentagon: Dissociated Press.
* primary Rmail file: Rmail Basics.
* primary selection: Mouse Commands.
* printing under MS-DOS: MS-DOS Processes.
* program building: Building.
* program editing: Programs.
* prompt: Minibuffer.
* properbose: Dissociated Press.
* puzzles: Amusements.
* query replace: Query Replace.
* quitting: Quitting.
* quitting (in search): Incremental Search.
* quitting Emacs: Exiting.
* quitting on MS-DOS: MS-DOS Input.
* quoting: Inserting Text.
* quoting file names: Quoted File Names.
* RCS: Version Systems.
* read-only buffer: Misc Buffer.
* reading mail: Rmail.
* reading netnews: Gnus.
* rebinding keys, permanently: Init File.
* rebinding keys, this session: Rebinding.
* rebinding major mode keys: Local Keymaps.
* rebinding mouse buttons: Mouse Buttons.
* rectangle: Rectangles.
* rectangles and Picture mode: Rectangles in Picture.
* recursive editing level: Recursive Edit.
* regexp: Regexp Search.
* regexp syntax: Regexps.
* region: Mark.
* region face: Faces.
* region highlighting: Transient Mark.
* registered file: VC Concepts.
* registers: Registers.
* regular expression: Regexp Search.
* remote file access: Remote Files.
* remote host: Remote Host.
* repeating a command: Repeating.
* replacement: Replace.
* reply to a message: Rmail Reply.
* REPLYTO environment variable: Mail Headers.
* reporting bugs: Checklist.
* Resize-Minibuffer mode: Minibuffer Edit.
* resolving conflicts: Merging.
* resources: Resources X.
* restriction: Narrowing.
* retrying a failed message: Rmail Reply.
* Rlogin: Remote Host.
* Rmail: Rmail.
* rot13 code: Rmail Rot13.
* running Lisp functions: Building.
* Russian: International.
* saved echo area messages: Echo Area.
* saving files: Visiting.
* saving keyboard macros: Save Kbd Macro.
* saving option value: Changing an Option.
* saving sessions: Saving Emacs Sessions.
* SCCS: Version Systems.
* screen: Screen.
* Scroll Bar mode: Scroll Bars.
* scrolling: Scrolling.
* scrolling in the calendar: Scroll Calendar.
* SDB: Debuggers.
* search-and-replace commands: Replace.
* searching: Search.
* searching in Rmail: Rmail Motion.
* secondary selection: Secondary Selection.
* selected buffer: Buffers.
* selected window: Basic Window.
* selecting buffers in other windows: Pop Up Window.
* selection, primary: Mouse Commands.
* selective display: Outline Mode.
* selective undo: Undo.
* self-documentation: Help.
* sending mail: Sending Mail.
* sending patches for GNU Emacs: Sending Patches.
* sentences: Sentences.
* server, using Emacs as: Emacs Server.
* setting a mark: Mark.
* setting option value: Changing an Option.
* setting variables: Examining.
* sexp: Lists.
* shell commands: Shell.
* shell commands, Dired: Shell Commands in Dired.
* SHELL environment variable: Interactive Shell.
* Shell mode: Shell Mode.
* Show Paren mode: Matching.
* simultaneous editing: Interlocking.
* single-frame terminals: Non-Window Terminals.
* size of minibuffer: Minibuffer Edit.
* slashes repeated in file name: Minibuffer File.
* SliTeX mode: TeX Mode.
* snapshots and version control: Snapshots.
* soft newline: Hard and Soft Newlines.
* sorting: Sorting.
* sorting Dired buffer: Dired Updating.
* speedbar: Speedbar.
* spelling, checking and correcting: Spelling.
* splitting columns: Two-Column.
* standard fontset: Defining Fontsets.
* starting Emacs: Entering Emacs.
* startup (command line arguments): Command Arguments.
* startup (init file): Init File.
* startup fontset: Defining Fontsets.
* stealth fontification: Lazy Lock Mode.
* string substitution: Replace.
* string syntax: Init Syntax.
* subdirectories in Dired: Subdirectories in Dired.
* subscribe groups: Summary of Gnus.
* subshell: Shell.
* subtree (Outline mode): Outline Visibility.
* summary (Rmail): Rmail Summary.
* sunrise and sunset: Sunrise/Sunset.
* Super (under MS-DOS): MS-DOS Input.
* suspending: Exiting.
* switch buffers: Select Buffer.
* switches (command line): Command Arguments.
* syntactic analysis: Syntactic Analysis.
* syntactic component: Syntactic Analysis.
* syntactic symbol: Syntactic Analysis.
* syntax highlighting: Font Lock.
* syntax table: Syntax.
* tab stops: Tab Stops.
* tables, indentation for: Tab Stops.
* tags completion: Symbol Completion.
* tags table: Tags.
* Tcl mode: Program Modes.
* techniquitous: Dissociated Press.
* television: Appending Kills.
* Telnet: Remote Host.
* TERM environment variable: Checklist.
* termscript file: Checklist.
* TeX mode: TeX Mode.
* TEXEDIT environment variable: Emacs Server.
* TEXINPUTS environment variable: TeX Print.
* text: Text.
* text and binary files on MS-DOS/MS-Windows: Text and Binary.
* Text mode: Text Mode.
* Thai: International.
* Tibetan: International.
* time (on mode line): Optional Mode Line.
* top level: Mode Line.
* tower of Hanoi: Amusements.
* Transient Mark mode: Transient Mark.
* transposition: List Commands.
* triple clicks: Mouse Buttons.
* truenames of files: File Aliases.
* truncation: Continuation Lines.
* trunk (version control): Branches.
* two-column editing: Two-Column.
* typos, fixing: Fixit.
* uncompression: Compressed Files.
* undeletion (Rmail): Rmail Deletion.
* undigestify: Rmail Digest.
* undo: Undo.
* undo limit: Undo.
* unibyte operation <1>: General Variables.
* unibyte operation: Initial Options.
* Unibyte operation: Single-Byte European Support.
* unibyte operation (MS-DOS): MS-DOS and MULE.
* unsubscribe groups: Summary of Gnus.
* untranslated file system: Text and Binary.
* user option: Variables.
* userenced: Dissociated Press.
* using tab stops in making tables: Tab Stops.
* variable: Variables.
* vc-resolve-conflicts: Merging.
* version control: Version Control.
* VERSION_CONTROL environment variable: Backup Names.
* vi: Emulation.
* Vietnamese: International.
* View mode: Misc File Ops.
* viewing: Misc File Ops.
* views of an outline: Outline Views.
* visiting files: Visiting.
* watching files (CVS): Backend Options.
* weeks, which day they start on: Move to Beginning or End.
* widening: Narrowing.
* Windows clipboard support: MS-DOS Input.
* windows in Emacs: Windows.
* word processing: Formatted Text.
* word search: Word Search.
* word wrap: Auto Fill.
* words: Words.
* words, case conversion: Case.
* work file: VC Concepts.
* wrapping: Continuation Lines.
* WYSIWYG: Formatted Text.
* X cutting and pasting: Mouse Commands.
* XDB: Debuggers.
* xon-xoff: Unasked-for Search.
* yahrzeits: From Other Calendar.
* yanking: Yanking.
* yanking previous kills: Earlier Kills.
* Zippy: Amusements.
* Zmacs mode: Transient Mark.