I'd like to bind Ctrl-` in tmux to select-pane.

I've tried: bind -n C-` select-pane -t :.+ Which gives me: unknown key C-`

I've also tried: bind -n 'C-`' select-pane -t :.+ Which gives me the same error.

I then tried just plain `: bind -n ` select-pane -t :.+ That worked fine (but bound ` not C-`.

Most confusingly, I tried: bind -n `-C select-pane -t :.+ Which surprisingly worked (I had to hit backtick first, and then ctrl). What is it within Ctrl-` that tmux doesn't like?

2 Answers 2


tmux uses this logic for handling the ctrl modifier in key-string.c (backtick is code 96):

    /* Convert the standard control keys. */                               
    if (key < KEYC_BASE && (modifiers & KEYC_CTRL) && !strchr(other, key)) {
            if (key >= 97 && key <= 122)
                    key -= 96;
            else if (key >= 64 && key <= 95)
                    key -= 64;
            else if (key == 32)
                    key = 0;
            else if (key == 63)
                    key = KEYC_BSPACE;
                    return (KEYC_NONE);
            modifiers &= ~KEYC_CTRL;

Although some applications may treat the whole range from 64 to 126 as valid for ctrl, tmux excludes backtic, curly braces, vertical bar and tilde. The likely reason is that they are less useful for key bindings because the unmodified keys are often used in shell scripts.

On the other hand, ctrl-@ would have the same expected interpretation, and you could use that instead.

  • I've tried C-@ and that didn't work (It selected panes with Ctrl+@ but not with Ctrl+`) :(
    – Jon Q
    Commented Jun 24, 2015 at 9:24
  • But as one can see (reading the source code), tmux does not do what was requested, unless you modify the program. Commented Jun 24, 2015 at 9:27

I found somewhere the advice to use cat inside tmux to check escape sequence.

  1. Run tmux
  2. Run cat
  3. Press keys C-`

On my terminal I've got ^@

So in the config I've put

set -g prefix ^@ Worked for me with roxterm

  • ^@ works well with tilix
    – ilyuha21st
    Commented Apr 9, 2021 at 21:42

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