21.15 Commands for Binding Keys

This section describes some convenient interactive interfaces for changing key bindings. They work by calling define-key.

People often use global-set-key in their init files (see Init File) for simple customization. For example,

(global-set-key (kbd "C-x C-\\") 'next-line)

or

(global-set-key [?\C-x ?\C-\\] 'next-line)

or

(global-set-key [(control ?x) (control ?\\)] 'next-line)

redefines C-x C-\ to move down a line.

(global-set-key [M-mouse-1] 'mouse-set-point)

redefines the first (leftmost) mouse button, entered with the Meta key, to set point where you click.

Be careful when using non-ASCII text characters in Lisp specifications of keys to bind. If these are read as multibyte text, as they usually will be in a Lisp file (see Loading Non-ASCII), you must type the keys as multibyte too. For instance, if you use this:

(global-set-key "ö" 'my-function) ; bind o-umlaut

or

(global-set-key ?ö 'my-function) ; bind o-umlaut

and your language environment is multibyte Latin-1, these commands actually bind the multibyte character with code 246, not the byte code 246 (M-v) sent by a Latin-1 terminal. In order to use this binding, you need to teach Emacs how to decode the keyboard by using an appropriate input method (see Input Methods in The GNU Emacs Manual).

Command: global-set-key key binding

This function sets the binding of key in the current global map to binding.

(global-set-key key binding)
≡
(define-key (current-global-map) key binding)

Command: global-unset-key key

This function removes the binding of key from the current global map.

One use of this function is in preparation for defining a longer key that uses key as a prefix—which would not be allowed if key has a non-prefix binding. For example:

(global-unset-key "\C-l")
    ⇒ nil

(global-set-key "\C-l\C-l" 'redraw-display)
    ⇒ nil

This function is equivalent to using define-key as follows:

(global-unset-key key)
≡
(define-key (current-global-map) key nil)

Command: local-set-key key binding

This function sets the binding of key in the current local keymap to binding.

(local-set-key key binding)
≡
(define-key (current-local-map) key binding)

Command: local-unset-key key

This function removes the binding of key from the current local map.

(local-unset-key key)
≡
(define-key (current-local-map) key nil)