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emacs / man / m-x.texi

@c This is part of the Emacs manual.
@c Copyright (C) 1985, 86, 87, 93, 94, 95, 1997 Free Software Foundation, Inc.
@c See file emacs.texi for copying conditions.
@node M-x, Help, Minibuffer, Top
@chapter 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, @code{auto-fill-mode} or
@code{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.

@kindex M-x
  The way to run a command by name is to start with @kbd{M-x}, type the
command name, and finish it with @key{RET}.  @kbd{M-x} uses the
minibuffer to read the command name.  @key{RET} exits the minibuffer and
runs the command.  The string @samp{M-x} appears at the beginning of the
minibuffer as a @dfn{prompt} to remind you to enter the name of a
command to be run.  @xref{Minibuffer}, for full information on the
features of the minibuffer.

  You can use completion to enter the command name.  For example, the
command @code{forward-char} can be invoked by name by typing

@example
M-x forward-char @key{RET}
@end example

@noindent
or

@example
M-x forw @key{TAB} c @key{RET}
@end example

@noindent
Note that @code{forward-char} is the same command that you invoke with
the key @kbd{C-f}.  You can run any Emacs command by name using
@kbd{M-x}, whether or not any keys are bound to it.

  If you type @kbd{C-g} while the command name is being read, you cancel
the @kbd{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
@kbd{M-x}, specify the numeric argument before the @kbd{M-x}.  @kbd{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.

@vindex suggest-key-bindings
  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 @kbd{M-x
forward-word}, the message says that you can run the same command more
easily by typing @kbd{M-f}.  You can turn off these messages by setting
@code{suggest-key-bindings} to @code{nil}.

  Normally, when describing in this manual a command that is run by
name, we omit the @key{RET} that is needed to terminate the name.  Thus
we might speak of @kbd{M-x auto-fill-mode} rather than @kbd{M-x
auto-fill-mode @key{RET}}.  We mention the @key{RET} only when there is
a need to emphasize its presence, such as when we show the command
together with following arguments.

@findex execute-extended-command
  @kbd{M-x} works by running the command
@code{execute-extended-command}, which is responsible for reading the
name of another command and invoking it.