49.3.6 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 initialization file by writing Lisp code. See Init File, for a description of the initialization file.

There are several ways to write a key binding using Lisp. The simplest is to use the kbd function, which converts a textual representation of a key sequence—similar to how we have written key sequences in this manual—into a form that can be passed as an argument to global-set-key. For example, here’s how to bind C-z to the shell command (see Interactive Shell):

(global-set-key (kbd "C-z") 'shell)

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 as a variable. This probably causes an error; it certainly isn’t what you want.

Here are some additional examples, including binding function keys and mouse events:

(global-set-key (kbd "C-c y") 'clipboard-yank)
(global-set-key (kbd "C-M-q") 'query-replace)
(global-set-key (kbd "<f5>") 'flyspell-mode)
(global-set-key (kbd "C-<f5>") 'display-line-numbers-mode)
(global-set-key (kbd "C-<right>") 'forward-sentence)
(global-set-key (kbd "<mouse-2>") 'mouse-save-then-kill)

Instead of using kbd, you can use a Lisp string or vector to specify the key sequence. Using a string is simpler, but only works for ASCII characters and Meta-modified ASCII characters. For example, here’s how to bind C-x M-l to make-symbolic-link (see Copying and Naming):

(global-set-key "\C-x\M-l" 'make-symbolic-link)

To bind a key sequence including TAB, RET, ESC, or DEL, the string should contain the Emacs Lisp escape sequence ‘\t’, ‘\r’, ‘\e’, or ‘\d’ respectively. Here is an example which binds C-x TAB to indent-rigidly (see Indentation):

(global-set-key "\C-x\t" 'indent-rigidly)

When the key sequence includes function keys or mouse button events, or non-ASCII characters such as C-= or H-a, you can use a vector to specify the key sequence. Each element in the vector stands for an input event; the elements are separated by spaces and surrounded by a pair of square brackets. 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. Function keys are represented by symbols (see Function Keys); simply write the symbol’s name, with no other delimiters or punctuation. Here are some examples:

(global-set-key [?\C-=] 'make-symbolic-link)
(global-set-key [?\M-\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:

(global-set-key [?\C-z ?\M-l] 'make-symbolic-link)

Language and coding systems may cause problems with key bindings for non-ASCII characters. See Init Non-ASCII.

As described in Local Keymaps, major modes and minor modes can define local keymaps. These keymaps are constructed when the mode is loaded for the first time in a session. The function define-key can be used to make changes in a specific keymap. This function can also unset keys, when passed nil as the binding.

Since a mode’s keymaps are not constructed until it has been loaded, you must delay running code which modifies them, e.g., by putting it on a mode hook (see Hooks). For example, Texinfo mode runs the hook texinfo-mode-hook. Here’s how you can use the hook to add local bindings for C-c n and C-c p, and remove the one for C-c C-x x 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)))
            (define-key texinfo-mode-map "\C-c\C-xx" nil)