The CICA Windows Explosion!/The CICA Windows Explosion! - Disc 2.iso/demo/wemdemo4.zip/INFO/LEMACS.3

GNU Info File | 1994-09-21 | 49KB | 843 lines

This is Info file ../info/lemacs, produced by Makeinfo-1.55 from the
input file lemacs.txi.
   This file documents the GNU Emacs editor.
   Copyright (C) 1985, 1986, 1988 Richard M. Stallman.  Copyright (C)
1991, 1992 Lucid, 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 author instead of in the original English.
File: lemacs,  Node: Minibuffer,  Next: M-x,  Prev: Undo,  Up: Top
The Minibuffer
**************
   Emacs commands use the "minibuffer" 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.  To edit the argument in the minibuffer, you can use Emacs
editing commands.
   When the minibuffer is in use, it appears in the echo area, and the
cursor moves there.  The beginning of the minibuffer line displays a
"prompt" indicating what kind of input you should supply and how it
will be used.  The prompt is often derived from the name of the command
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 is used as the
argument value if you enter an empty argument (e.g., 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 give a minibuffer argument is to type the text
you want, terminated by RET to exit the minibuffer.  To get out of the
minibuffer and cancel the command that it was for, type `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 you use a command in the minibuffer whose purpose is to print a
     message in the echo area (for example `C-x =') the message is
     displayed 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.
* Menu:
* File: Minibuffer File.  Entering file names with the minibuffer.
* Edit: Minibuffer Edit.  How to edit in the minibuffer.
* Completion::          An abbreviation facility for minibuffer input.
* Repetition::          Re-executing commands that used the minibuffer.
File: lemacs,  Node: Minibuffer File,  Next: Minibuffer Edit,  Prev: Minibuffer,  Up: Minibuffer
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
informs you in which directory the file will be found if you do not
specify one.  For example, the minibuffer might start out with
     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', the file that you visit
will be the one named
`/u2/emacs/lisp/simple.el'.  Alternatively, you can use  `M-DEL' to
kill directory names you don't want (*note Words::.).
   You can also type an absolute file name, one starting with a slash
or a tilde, ignoring the default directory.  For example, to find the
file `/etc/termcap', just type the name, giving
     Find File: /u2/emacs/src//etc/termcap
Two slashes in a row are not normally meaningful in Unix file names, but
they are allowed in GNU Emacs.  They mean, "ignore everything before the
second slash in the pair."  Thus, `/u2/emacs/src/' is ignored, 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.
File: lemacs,  Node: Minibuffer Edit,  Next: Completion,  Prev: Minibuffer File,  Up: Minibuffer
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
must use `C-o' or `C-q LFD' to insert a newline into the minibuffer.
(Recall that a newline is really the LFD character.)
   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. The minibuffer 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, however, some restrictions on the use of the minibuffer
window.  You cannot switch buffers in it--the minibuffer and its window
are permanently attached.  You also cannot split or kill the minibuffer
window, but you can make it taller with `C-x ^'.
   If you are in the minibuffer and issue a command that displays help
text in another window, that window will be scrolled if you type
`C-M-v' while in the minibuffer until you exit the minibuffer.  This
feature is helpful if a completing minibuffer gives you a long list of
possible completions.
   If the variable `minibuffer-confirm-incomplete' is `true', you are
asked for confirmation if there is no known completion for the text you
typed. For example, if you attempted to visit a non-existent file, the
minibuffer might read:
             Find File:chocolate_bar.c [no completions, confirm]
   If you press `Return' again, that confirms the filename. Otherwise,
you can continue editing it.
   Emacs supports recursive use of the minibuffer.  However, it is easy
to do this by accident (because of autorepeating keyboards, for
example) and get confused.  Therefore, most Emacs commands that use the
minibuffer refuse to operate if the minibuffer window is selected.  If
the minibuffer is active but you have switched to a different window,
recursive use of the minibuffer is allowed--if you know enough to try
to do this, you probably will not get confused.
   If you set the variable `enable-recursive-minibuffers' to be
non-`nil', recursive use of the minibuffer is always allowed.
File: lemacs,  Node: Completion,  Next: Repetition,  Prev: Minibuffer Edit,  Up: Minibuffer
Completion
==========
   When appropriate, the minibuffer provides a "completion" facility.
You type the beginning of an argument and one of the completion keys,
and Emacs visibly fills in the rest, depending on what you have already
typed.
   When completion is available, certain keys--TAB, RET, and SPC--are
redefined to complete an abbreviation 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 the minibuffer is being used by `Meta-x' to read
the name of a command, it is given 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
characters of the name that are implied by the ones already present in
the minibuffer, and add those characters to the ones you have given.
   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' will not complete to `Foo'.
When you are completing a name in which case does not matter, case may
be ignored for completion's sake if specified by program.
   When a completion list is displayed, the completions will highlight
as you move the mouse over them.  Clicking middle on any highlighted
completion will "select" it just as if you had typed it in and hit RET.
Completion Example
------------------
   Consider the following example.  If you type `Meta-x au TAB', TAB
looks for alternatives (in this case, command names) that start with
`au'.  There are only two commands: `auto-fill-mode' and
`auto-save-mode'.  They are 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 `s' or `f'--so no more
characters are added; but a list of all possible completions is
displayed 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
inserts the rest of that command.  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 function
`minibuffer-complete' when completion is supposed to be done.
Completion Commands
-------------------
   Here is a list of all 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 text in the minibuffer but don't add or fill out more
     than 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').
`button2'
     Select the highlighted text under the mouse as a minibuffer
     response.  When the minibuffer is being used to prompt the user
     for a completion, any valid completions which are visible on the
     screen will highlight when the mouse moves over them.  Clicking
     button2 will select the highlighted completion and exit the
     minibuffer.  (`minibuf-select-highlighted-completion').
   SPC completes similar to 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-'. The result is `auto-fill-'.  Another SPC at this point
completes all the way to `auto-fill-mode'.  SPC in the minibuffer runs
the function `minibuffer-complete-word' when completion is available.
   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 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.  Typing `?' explicitly requests such a list.  The list
of completions counts as help text, so `C-M-v' typed in the minibuffer
scrolls the list.
   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' completes to `foo.c' even though
`foo.o' exists as well.  If the only possible completions are files
that end in "ignored" strings, they are not ignored.
   If a completion command finds the next character is undetermined, it
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.
   If the variable `minibuffer-confirm-incomplete' is set to true, then
in contexts where `completing-read' allows answers that are not valid
completions, an extra RET must be typed to confirm the response.  This
is helpful for catching typos, etc.
File: lemacs,  Node: Repetition,  Prev: Completion,  Up: Minibuffer
Repeating Minibuffer Commands
=============================
   Every command that uses the minibuffer at least once is recorded on a
special history list, together with the values of the minibuffer
arguments, so that you can repeat the command easily.  In particular,
every use of `Meta-x' is recorded, since `M-x' uses the minibuffer to
read the command name.
`C-x ESC'
     Re-execute a recent minibuffer command
     (`repeat-complex-command').
`M-p'
     Within `C-x ESC', move to previous recorded command
     (`previous-complex-command').
`M-n'
     Within `C-x ESC', move to the next (more recent) recorded command
     (`next-complex-command').
`M-x list-command-history'
     Display the entire command history, showing all the commands `C-x
     ESC' can repeat, most recent first.
   `C-x ESC' is used to re-execute a recent command that used the
minibuffer. With no argument, it repeats the last command.  A numeric
argument specifies which command to repeat; 1 means the last one, and
larger numbers specify earlier commands.
   `C-x 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.
The expression you finally submit 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, you can be sure the command will repeat exactly as before.
   If you are in the minibuffer for `C-x ESC' and the command shown to
you is not the one you want to repeat, you can move around the list of
previous commands using `M-n' and `M-p'.  `M-p' replaces the contents
of the minibuffer with the next earlier recorded command, and `M-n'
replaces it with the next later command.  After finding the desired
previous command, you can edit its expression and then resubmit it by
typing RET.  Any editing you have done on the command to be repeated is
lost if you use `M-n' or `M-p'.
   `M-n' and `M-p' are specially defined within `C-x ESC' to run the
commands `previous-complex-command' and `next-complex-command'.
   The list of previous commands using the minibuffer is stored as a
Lisp list in the variable `command-history'.  Each element of the list
is a Lisp expression which describes one command and its arguments.
Lisp programs can reexecute a command by feeding the corresponding
`command-history' element to `eval'.
File: lemacs,  Node: M-x,  Next: Help,  Prev: Minibuffer,  Up: Top
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 are used more rarely are not bound to keys;
to run them, you must refer to them by name.
   A command name consists, by convention, 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 results in more
characters to type.  You can run any command by name, even if it can be
run by keys as well.
   To run a command by name, to start with `M-x', then type the command
name, and finish with RET.  `M-x' uses the minibuffer to read the
command name.  RET exits the minibuffer and runs the command.
   Emacs uses the minibuffer for reading input for many different
purposes; on this occasion, the string `M-x' is displayed at the
beginning of the minibuffer as a "prompt" to remind you that your input
should be 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 a command name.  For example, to
invoke the command `forward-char', type:
     M-x forward-char RET
   or
     M-x fo TAB c RET
Note that `forward-char' is the same command that you invoke with the
key `C-f'.  You can call any command (interactively callable function)
defined in Emacs by its name using `M-x' whether or not any keys are
bound to it.
   If you type `C-g' while Emacs reads the command name, you cancel the
`M-x' command and get out of the minibuffer, ending up at top level.
   To pass a numeric argument to a command you are invoking with `M-x',
specify the numeric argument before the `M-x'.  `M-x' passes the
argument along to the function that it calls.  The argument value
appears in the prompt while the command name is being read.
   You can use the command `M-x interactive' to specify a way of
parsing arguments for interactive use of a function.  For example, write
       (defun foo (arg) "Doc string" (interactive "p") ...use arg...)
   to make ARG be the prefix argument when `foo' is called as a
command.  The call to `interactive' is actually a declaration rather
than a function; it tells `call-interactively' how to read arguments to
pass to the function.  When actually called, `interactive' returns
`nil'.
   The argument of INTERACTIVE is usually a string containing a code
letter followed by a prompt.  Some code letters do not use I/O to get
the argument and do not need prompts.  To prompt for multiple arguments,
you must provide a code letter, its prompt, a newline, and another code
letter, etc.  If the argument is not a string, it is evaluated to get a
list of arguments to pass to the function.  If you do not provide an
argument to `interactive', no arguments are passed when calling
interactively.
   Available code letters are:
     Function name: symbol with a function definition.
     Name of existing buffer.
     Name of buffer, possibly nonexistent.
     Character.
     Command name: symbol with interactive function definition.
     Value of point as number.  Does not do I/O.
     Directory name.
     Last mouse event.
     Existing file name.
     Possibly nonexistent file name.
     Key sequence (string).
     Value of mark as number.  Does not do I/O.
     Number read using minibuffer.
     Prefix arg converted to number, or if none, do like code `n'.
     Prefix arg converted to number.  Does not do I/O.
     Prefix arg in raw form.  Does not do I/O.
     Region: point and mark as two numeric arguments, smallest first.
     Does not do I/O.
     Any string.
     Any symbol.
     Variable name: symbol that is `user-variable-p'.
     Lisp expression read but not evaluated.
     Lisp expression read and evaluated.
   In addition, if the string begins with `*', an error is signaled if
the buffer is read-only.  This happens before reading any arguments.
If the string begins with `@', the window the mouse is over is selected
before anything else is done.  You may use both `@' and `*'; they are
processed in the order that they appear.
   Normally, when describing a command that is run by name, we omit the
RET that is needed to terminate the name.  Thus we may refer to `M-x
auto-fill-mode' rather than `M-x auto-fill-mode' RET.  We mention the
RET only when it it necessary to emphasize its presence, for example,
when describing a sequence of input that contains a command name and
arguments that follow it.
   `M-x' is defined to run the command `execute-extended-command',
which is responsible for reading the name of another command and
invoking it.
File: lemacs,  Node: Help,  Next: Mark,  Prev: M-x,  Up: Top
   Emacs provides extensive help features which revolve around a single
character, `C-h'.  `C-h' is a prefix key that is used only for
documentation-printing commands.  The characters you can type after
`C-h' are called "help options".  One help option is `C-h'; you use it
to ask for help about using `C-h'.
   `C-h C-h' prints a list of the possible help options, and then asks
you to type the desired option.  It prompts with a string
     A, B, C, F, I, K, L, M, N, S, T, V, W, C-c, C-d, C-n, C-w or C-h for more help:
You should type one of those characters.
   Typing a third `C-h' displays a description of what the options mean;
Emacs still waits for you to type an option.  To cancel, type `C-g'.
   Here is a summary of the defined help commands.
`C-h a STRING RET'
     Display list of commands whose names contain STRING (`command-
     apropos').
`C-h b'
     Display a table of all key bindings in effect now; local bindings
     of the current major mode first, followed by all global bindings
     (`describe-bindings').
`C-h c KEY'
     Print the name of the command that KEY runs (`describe-key-
     briefly').  `c' is 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').  Note that commands are Lisp functions, so
     a command name may be used.
`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 name and documentation of the command 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'
     Display a table of all mouse bindings in effect now; local bindings
     of the current major mode first, followed by all global bindings
     (`describe-pointer').
`C-h s'
     Display current contents of the syntax table, plus an explanation
     of what they mean (`describe-syntax').
`C-h t'
     Display the Emacs 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').
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 the name of the command that KEY
is bound to in the echo area.  For example, `C-h c C-f' prints
`forward-char'.  Since command names are chosen to describe what the
command does, using this option is a good way to get a somewhat cryptic
description of what KEY does.
   `C-h k KEY' is similar to `C-h c' but gives more information.  It
displays the documentation string of the function KEY is bound to as
well as its name.  KEY is a string or vector of events.  When called
interactvely, KEY may also be a menu selection.  This information does
not usually fit into the echo area, so a window is used for the display.
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 the
argument FUNCTION to get the documentation of a command that you know
by name.  For example,
     C-h f auto-fill-mode RET
displays the documentation for `auto-fill-mode'. Using `C-h f' is the
only way to see the documentation of a command that is not bound to any
key, that is, a command you would normally call using `M-x'.  If the
variable `describe-function-show-arglist' is `t', `describe-function'
shows its arglist if the FUNCTION is not an autoload function.
   `C-h f' is also useful for Lisp functions you are planning to use in
a Lisp program.  For example, if you have just written the code
`(make-vector len)' and want to make sure 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.
   If you type RET, leaving the minibuffer empty, `C-h f' by default
describes 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
starting 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 default in the
prompt, you have typed the name of a defined Lisp function.  If that is
what you wanted to know, just type `C-g' to cancel the `C-h f' command
and continue 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.  Alternatively, it informs
you that a command is not bound to any keys, which implies that you
must use `M-x' to call the command.
   `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, if that is the name of a known Lisp variable.
*Note Variables::.
Apropos
=======
   It is possible to ask a question like, "What are the commands for
working with files?"  To do this, type `C-h a file RET', which displays
a list of all command names that contain `file', such as `copy-file',
`find-file', and so on.  With each command name a brief description of
its use and information on the keys you can use to invoke it is
displayed.  For example, you would be informed 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 Lisp function `command-apropos'.
   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 commands, don't give up.  Try
just `kill', or just `backwards', or just `back'.  Be persistent.
Pretend you are playing Adventure.  Also note that you can use a
regular expression as the argument (*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
standard Emacs commands.  By giving you a feeling for the naming
conventions, this set of arguments can also help you develop a
technique for picking `apropos' strings.
     char, line, word, sentence, paragraph, region, page, sexp, list,
     defun, buffer, screen, window, 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.
   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'.
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 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.  If you see commands you don't know, use
`C-h c' to find out what they do.
   Emacs has several major modes. Each mode 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 information about the current Emacs mode that is not covered by
`C-h m'.  `C-h b' displays a list of all key bindings now in effect;
the local bindings of the current major mode first, followed by 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::.).
   The other `C-h' options display various files of useful information.
`C-h C-w' displays 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 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 another file named `emacs/etc/DISTRIB', which tells you how
you can order a copy of the latest version of Emacs.
File: lemacs,  Node: Mark,  Next: Killing,  Prev: Help,  Up: Top
Selecting Text
**************
   Many Emacs commands operate on an arbitrary contiguous part of the
current buffer. You can select text in two ways:
   * You use special keys to select text by defining a region between
     point and the mark.
   * If you are running Lucid GNU Emacs under X, you can also select
     text with the mouse.
The Mark and the Region
=======================
   To specify the text for a command to operate on, 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".  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 until it is set again at
another place.  The mark remains fixed with respect to the preceding
character if text is inserted or deleted in a buffer.  Each Emacs
buffer has its own mark; 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 the mark at one end of the inserted text--the
opposite end from where point is positioned, so that the region
contains the text just inserted.
   Aside from delimiting the region, the mark is useful for marking a
spot that you may want to go back to.  To make this feature more useful,
Emacs remembers 16 previous locations of the mark in the `mark ring'.
* Menu:
* Setting Mark::    Commands to set the mark.
* Using Region::    Summary of ways to operate on contents of the region.
* Marking Objects::    Commands to put region around textual units.
* Mark Ring::       Previous mark positions saved so you can go back there.
* Using X Selections::  Using the mouse to mark a region if running under X.
File: lemacs,  Node: Setting Mark,  Next: Using Region,  Prev: Mark,  Up: Mark
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').
`C-<'
     Pushes a mark at the beginning of the buffer.
`C->'
     Pushes a mark at the end of the buffer.
   For example, to convert part of the buffer to all upper-case, you
can use the `C-x C-u' (`upcase-region') command, which operates on the
text in the region.  First go to the beginning of the text you want to
capitalize and type `C-SPC' to put the mark there, then move to the
end, and then type `C-x C-u' to capitalize the selected region.  You
can also set the mark at the end of the text, move to the beginning,
and then type `C-x C-u'.  Most commands that operate on the text in the
region have the word `region' in their names.
   The most common way to set the mark is with the `C-SPC' command
(`set-mark-command').  This command sets the mark where point is. You
can then move point away, leaving the mark behind.  It is actually
incorrect to speak of the character `C-SPC'; there is no such
character.  When you type SPC while holding down CTRL, you get the
character `C-@' on most terminals. This character 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 should think
of this character as `C-SPC'.
   Since terminals have only one cursor, Emacs cannot show you where the
mark is located. Most people use the mark soon after they set it, before
they forget where it is. But 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 location of
the mark.
   Another way to set the mark is to push the mark to the beginning of a
buffer while leaving point at its original location. If you supply an
argument to `C-<' (`mark-bob'), the mark is pushed N/10 of the way from
the true beginning of the buffer. You can also set the mark at the end
of a buffer with `C->' (`mark-eob'). It pushes the mark to the end of
the buffer, leaving point alone. Supplying an argument to the command,
pushes the mark N/10 of the way from the true end of the buffer.
   If you are using Lucid GNU Emacs under the X window system, you can
set the variable `zmacs-regions' to `t'. This makes the current region
(defined by point and mark) highlight and makes it available as the X
clipboard selection, which means you can use the menu bar items on it.
*Note Active Regions:: for more information.
   `C-x C-x' is also useful when you are satisfied with the location of
point but want to move the mark; do `C-x C-x' to put point there and
then you can move it.  A second use of `C-x C-x', if necessary, puts
the mark at the new location with point back at its original location.
* Menu:
* Active Regions::  Having the region highlight while working under X.
File: lemacs,  Node: Using Region,  Next: Marking Objects,  Prev: Setting Mark,  Up: Mark
Operating on the Region
-----------------------
   Once you have created an active region, you can do many things to
the text in it:
   * Kill it with `C-w' (*note Killing::.).
   * Save it in a register with `C-x x' (*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::.).
   * Evaluate it as Lisp code with `M-x eval-region' (*note Lisp
     Eval::.).
   * Fill it as text with `M-g' (*note Filling::.).
   * Print hardcopy with `M-x print-region' (*note Hardcopy::.).
   * Indent it with `C-x TAB' or `C-M-\' (*note Indentation::.).
File: lemacs,  Node: Marking Objects,  Next: Mark Ring,  Prev: Using Region,  Up: Mark
Commands to Mark Textual Objects
--------------------------------
   There are 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 characters sometimes save you some typing.
   A number of commands are available that set both point and mark and
thus delimit an object in the buffer.  `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::.).  You can then indent, case-convert, or kill the whole
paragraph.  In the same fashion, `C-M-h' (`mark-defun') 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
(or the next or previous, depending on the argument), 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).  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.
File: lemacs,  Node: Mark Ring,  Prev: Marking Objects,  Up: Mark
The Mark Ring
-------------
   Aside from delimiting the region, the mark is also useful for marking
a spot that you may want to go back to.  To make this feature more
useful, Emacs remembers 16 previous locations of the mark in the "mark
ring".  Most commands that set the mark 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.  The
command moves point to where the mark was, and restores the mark from
the ring of former marks. Repeated use of this command moves point to
all the old marks on the ring, one by one.  The marks you have seen go
to the end of the ring, so no marks are lost.
   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 makes it easier for you to move back
later.  Searches set the mark, unless they do not actually move point.
When a command sets the mark, `Mark Set' is printed in the echo area.
   The variable `mark-ring-max' is the maximum number of entries to
keep in the mark ring.  If that many entries exist and another entry is
added, the last entry in the list is discarded.  Repeating `C-u C-SPC'
circulates through the entries that are currently in the ring.
   The variable `mark-ring' holds the mark ring itself, as a list of
marker objects in the order most recent first.  This variable is local
in every buffer.
File: lemacs,  Node: Mouse Selection,  Next: Entering Emacs,  Prev: Pull-Down Menus,  Up: Top
Selecting Text with the Mouse
=============================
   If you are using Lucid GNU Emacs under X, you can use the mouse
cursor to select text. There are two mouse cursor shapes:
   * When the mouse cursor is over text, it appears as an I-beam, the
     same cursor that `xterm' uses.
   * When the mouse cursor is not over text, it appears as a plus sign
     (+).
   You can set the value of the variable `x-mode-pointer-shape' to
determine the shape of the mouse pointer when it is over the modeline.
If the value is `nil', the variable `x-nontext-pointer-shape' or the
variable `x-pointer-shape' is used.
   If you want to get fancy, you can set the foreground and background
colors of the mouse pointer with the variables
`x-pointer-background-color' and `x-pointer-foreground-color'.
   There are two ways to select a region of text with the mouse:
   To select a word in text, double click with the left mouse button
while the mouse cursor is over the word.  The word is highlighted when
selected. On monochrome monitors, a stipled background indicates that a
region of text has been highlighted. On color monitors, a color
background indicates highlighted text. You can triple-click to select
whole lines.
   To select an arbitrary region of text:
  1. Move the mouse cursor over the character at the beginning of the
     region of text you want to select.
  2. Press and hold the left mouse button.
  3. While holding the left mouse button down, drag the cursor to the
     character at the end of the region of text you want to select.
  4. Release the left mouse button.
        The selected region of text is highlighted.
   Once a region of text is selected, it becomes the primary X selection
(*note Using X Selections::.) as well as the Emacs selected region. You
can paste it into other X applications and use the options from the
Edit pull-down menu on it.  Since it is also the Emacs region, you can
use Emacs region commands on it.
Additional Mouse Operations
---------------------------
   Lucid GNU Emacs also provides the following mouse functions.  Most
of these are not bound to mouse gestures by default, but they are
provided for your customization pleasure.  For example, if you wanted
`shift-left' (that is, holding down the shift key and clicking the left
button) to delete the character at which you are pointing, then you
could do this:
     (global-set-key '(shift button1) 'mouse-del-char)
`mouse-del-char'
     Delete the character pointed to by the mouse.
`mouse-delete-window'
     Delete the Emacs window that the mouse is on.
`mouse-keep-one-window'
     Select the Emacs window that the mouse is on, then delete all other
     windows on this screen.
`mouse-kill-line'
     Kill the line pointed to by the mouse.
`mouse-line-length'
     Print the length of the line indicated by the pointer.
`mouse-scroll'
     Scroll point to the mouse position.
`mouse-select'
     Select the Emacs window the mouse is on.
`mouse-select-and-split'
     Select the Emacs window mouse is on, then split it vertically in
     half.
`mouse-set-mark'
     Select the Emacs window the mouse is on and set the mark at the
     mouse position.  Display the cursor at that position for a second.
`mouse-set-point'
     Select the Emacs window that the mouse is on and move point to the
     mouse position.
`mouse-track'
     Make a selection with the mouse.   This is the default binding of
     the left mouse button (button1).
`mouse-track-adjust'
     Extend the existing selection.  This is the default binding of
     shift-button1.
`mouse-track-and-copy-to-cutbuffer'
     Make a selection like `mouse-track', but also copy it to the cut
     buffer.
`mouse-track-delete-and-insert'
     Make a selection with the mouse and insert it at point.  This is
     the default binding of control-shift-button1.
`mouse-track-insert'
     Make a selection with the mouse and insert it at point.  This is
     the default binding of control-button1.
`mouse-window-to-region'
     Narrow a window to the region between the cursor and the mouse
     pointer.
   The `M-x mouse-track' command should be bound to a mouse button.  If
you click-and-drag, the selection is set to the region between the
point of the initial click and the point at which you release the
button.  These positions do not need to be ordered.
   If you click-and-release without moving the mouse, the point is
moved, and the selection is disowned (there will be no selection
owner.)  The mark will be set to the previous position of point.
   If you double-click, the selection will extend by symbols instead of
by characters.  If you triple-click, the selection will extend by lines.
   If you drag the mouse off the top or bottom of the window, you can
select pieces of text that are larger than the visible part of the
buffer; the buffer will scroll as necessary.
   The selected text becomes the current X selection, and is also
copied to the top of the kill ring.  Point will be left at the position
at which you released the button and the mark will be left at the
initial click position.  Bind a mouse click to
`mouse-track-and-copy-to-cutbuffer' to copy selections to the cut
buffer.
   See also the `mouse-track-adjust' command, on `Sh-button1'.
   The `M-x mouse-track-adjust' command should be bound to a mouse
button.  The selection will be enlarged or shrunk so that the point of
the mouse click is one of its endpoints.  This is only meaningful after
the `mouse-track' command (button1) has been executed.
   The `M-x mouse-track-delete-and-insert' command is exactly the same
as the `mouse-track' command on button1, except that point is not
moved; the selected text is immediately inserted after being selected;
and the text of the selection is deleted.
   The `M-x mouse-track-insert' command is exactly the same as the
`mouse-track' command on button1, except that point is not moved; the
selected text is immediately inserted after being selected; and the
selection is immediately disowned afterwards.