57.4.11 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.) You can also type ! to enable all commands,
for the current session only.
The direct mechanism for disabling a command is to put a
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 displayed 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. See Init File.
If Emacs was invoked with the -q or --no-init-file
options (see Initial Options), it will not edit your
~/.emacs init file. This is because editing the init file from
such a session might overwrite the lines you might have on your init
file which enable and disable commands.
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.