In general I have key bindings as follows:

(define-key isearch-mode-map (kbd "C-h") 'isearch-del-char)

Now I want to define a key binding for C-= (Control plus equal sign, which is next to Backspace on my keyboard); where it does not work.

Is it possible to do it?

  • 3
    Terminal emacs or GUI emacs? You may be able to do it in GUI emacs, but probably not in the terminal.
    – NickD
    May 6, 2020 at 14:25
  • I meant terminal emacs, I am not good with gui @NickD
    – alper
    May 6, 2020 at 18:11
  • 2
    Say C-h c C-= in your emacs and see what it says: if it says = runs the command self-insert-command then it does not recognize C-= (note that you asked it about C-= and it answered about =). If it says C-= is undefined then you should be able to change it.
    – NickD
    May 6, 2020 at 18:59
  • You are right, it returns as: = runs the command self-insert-command
    – alper
    May 7, 2020 at 1:27

1 Answer 1


Without more context, the direct answer to "is it possible to generate a keybinding for C-=" is "Yes".

For example,

(global-set-key (kbd "C-=") (lambda () (interactive) (message "Hello world!")))

There are many other ways. For instance, my init contains the following use-package definition:

(use-package expand-region
  :ensure t
  :bind (("C-=" . er/expand-region)
         ("C-+" . er/contract-region)))

Both of these define global keybindings.

Key map specific bindings can be defined like you state in the question. An example of this, again taken from my init, defines the <insert> key to insert an Org structure template only for buffers with Org mode enabled:

(define-key org-mode-map (kbd "<insert>") 'org-insert-structure-template)
  • 3
    That is possible on GUI emacs and maybe terminal emacs for some terminals, but certainly not all of them (e.g. try it in gnome-terminal with emacs -nw).
    – NickD
    May 6, 2020 at 19:01

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