How to turn off alternative Enter with Ctrl+M in Linux

Question

Why is Ctrl+M bound to Enter in Ubuntu Jaunty? How to turn it off?

I\'m using Emacs and would like to bind Ctrl+M to some other command.

Answer 1

Note: The issue isn't limited to Linux, it exists on Windows (and presumably Mac) as well. Read the other (non stack-overflow) source of all knowledge: Wikipedia on Carriage Return.

If you want to rebind C-m, be sure to all bind otherwise you run the risk of no longer being able to use the Enter/Return key. Also, in a terminal, Emacs cannot distinguish between the two (C-m and ).

In a plain Emacs, the Enter/Return key is bound to , which is (by default) translated to RET (same thing as C-m). If you only rebound the C-m, you'd also be affecting the Enter/Return key.

Try C-h k and you'll see

RET (translated from )

So, rebind both in the appropriate keymap to make sure you get the behavior you want.

It might be instructive to play with the following code:

(defun my-return ()
  (interactive)
  (message "return"))
(defun my-ret ()
  (interactive)
  (message "RET"))
(defun my-c-m ()
  (interactive)
  (message "C-m"))
(global-set-key (kbd "") 'my-return)
(global-set-key (kbd "C-m") 'my-c-m)
(global-set-key (kbd "RET") 'my-ret)

Put that in your *scratch* buffer and press C-j after each line (to evaluate the sexp). Then play with the Enter/Return keys and C-m.