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Looking for a new convenient keybinding for a frequently used command I stumbled upon Ctrl-M which is the same as Return/Enter.

What is the point of this binding? Can it cause some problem if I overwrite it?

Tom
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  • This recent related Q&A might also be helpful: https://emacs.stackexchange.com/a/52328/454 – phils Sep 05 '19 at 21:40

1 Answers1

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ASCII control character Control M is a carriage-return character. It is return, and its ASCII name is RET. That's the reason why C-m in Emacs is RET.

In terminal mode (no graphic display) Emacs does not have a <return> (pseudo-)function key. There is only the RET key, also known as C-m.

In a graphic-display Emacs has both a <return> key and a RET (C-m) key. You can bind either of them to whatever command you like.

If <return> is not explicitly bound then when you use <return> the binding of RET takes effect.

This is for convenience - it's the same principle that lets key M act as key m if m is bound to a command and M is not explicitly bound to a command.

As @phils mentioned in a comment here, see also C-h i g (elisp)Function Keys.

Drew
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  • So I if used Emacs in terminal (I don't) then I shouldn't rebind C-m, because then RET wouldn't work either? – Tom Sep 05 '19 at 17:36
  • If you rebind `C-m` then you've just rebound `RET`. They are the same thing. Whether rebinding it breaks something or not is another question. It likely won't "break" anything, but sometimes when you think `RET` (`C-m`) will do one thing it might do another instead. It depends on the keymap you rebind it in etc. – Drew Sep 05 '19 at 18:25
  • See also: `C-h i g (elisp)Function Keys` – phils Sep 05 '19 at 21:37
  • @phils: Thx; I added that to the answer. – Drew Sep 06 '19 at 00:18