I am having lots of issues with tmux on Mac.

One problem I have is that I cannot bind a key in my tmux.conf to resize my panes.

What I need is the CTRL-b: resize-pane -U 10. I'm trying to increase the size of the pane upwards ten cells (or downwards or left or right) using a key shortcut instead of having to type this over and over (which I currently do unfortunately).

But I cannot find a way to configure this since on Mac, it seems that CTRL and other keys work differently on Linux.

3 Answers 3


Below are my keybindings that let me resize a pane.

It uses Alt + direction, where the keys for the directions are the same as in Vim:

h l
# Resize the current pane using Alt + direction
bind -n M-k resize-pane -U 5
bind -n M-j resize-pane -D 5
bind -n M-h resize-pane -L 5
bind -n M-l resize-pane -R 5

In ~/.tmux.conf:

bind e resize-pane -U 10

Then, tmux source-file ~/.tmux.conf. (another useful shortcut: use the same principle).

  • 2
    1) So bind e resize-pane -U 10 is one line in tmux that binds the key e with the resize? Should I have pressed the ctrl-b before e? 2) I am not sure what you mean with tmux source-file ~/.tmux.conf. Doesn't tmux read the home directory's conf file?
    – Jim
    Commented Jul 4, 2013 at 19:43
  • @Jim: Yes, you hit the prefix key first. Then e. Yes, tmux does that, but it is faster to have it as a shortcut as well, so you don't have to restart tmux every time you make an improvement/extension in/to the init file. Commented Jul 4, 2013 at 19:44
  • So tmux source-file ~/.tmux.conf is another line in tmux.conf?
    – Jim
    Commented Jul 4, 2013 at 19:46
  • @Jim: No, that would be something you type. In the init file, it could look like this: bind u source-file ~/.tmux.conf if you want this for u. Commented Jul 4, 2013 at 19:50
  • 1
    why are you using bind and not bind-key? Commented Jan 28, 2016 at 22:04

There is already a shortcut: Hold down Ctrl, press b and then adjust the size with , etc. without releasing Ctrl.

Also, with

set -g mouse on

in ~/.tmux.conf you do it with the mouse. But with this setting active you need to hold Shift to do selections and paste with the scroll wheel.

  • 1
    doesnt work on mac unfortunately as ctrl+direction brings up mac window switcher Commented Feb 6, 2021 at 11:31
  • 3
    Hey @JimmyMGLim , if you want you can disable ctrl+arrows shortcuts on MacOS: go to "Preferences -> Keyboard -> Shortcut -> Mission Control" and remove the checks on all four ctrl+arrow lines. I did it (I don't use those OS shortcuts anyway) and it works great. :) apple.stackexchange.com/questions/18043/… Commented Mar 2, 2021 at 15:22
  • Is there a way to make this faster? this approach takes forever to make big adjustments.
    – azizj
    Commented Mar 16, 2021 at 14:20
  • @azizj1 I updated the answer. Commented Mar 26, 2021 at 19:41

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