I am using Mac OSX Lion. I have checked "Use Option key as Meta" in Terminal preferences. Although the Option key seems to work fine as Meta in Bash, when I use it in Tmux (over SSH) it does not work properly. I am trying to use TMUX shortcuts like ^b M-1 b M-2 etc. I can get these with the ESC key but not the Option key.

  • ^b Space with cycle through the various layouts – caspyin Mar 22 '14 at 14:03
up vote 11 down vote accepted

I would suggest using iTerm2 instead of the default Terminal.app, as it is better for many reasons.

Specifically, you would be interested in iTerm2's options to map left/right option as "+Esc", which works much better than trying to have it emulate Meta for every purpose I can think of or have tried.

This setting is located under:

  • Preferences
    • Profiles
      • [select a profile]
        • Keys
  • 1
    I was looking for a reason to move to iTerm2 and here I have it. Thanks!! – Phani Sep 27 '13 at 17:32
  • 11
    May I ask why you choose to set option to "+Esc" and not to "Meta" when it sounds like you're trying to use Meta-keys? What is the difference / why is "+Esc" better? Thanks! – NHDaly Mar 1 '14 at 19:15

For other folks who find their way here via their favorite search engine, I was able to solve this problem by simply going to Preferences -> Profiles -> Keyboard and checking "Use Option as Meta key" for the terminal profile I'm using.

I'm running weechat under tmux, and default key bindings make heavy use of the meta key.

I had the same problem and none of the answers provided here worked. That is, I too had the iTerm2 [Option] key remapped to [+Esc] (aka. "fallback"-[META]) in my "Preferences -> Profiles -> Keyboard", as described in the other answers, but still could not change my tmux pane layout with [CTRL]-[b], [+Esc/META]-[DIGIT].

Then I found that under "Preferences -> Keys", there is a "Navigation Shortcuts" where [Option] + (any) [DIGIT] is mapped to "switch split panes" (remember [Option] is remapped to [+Esc], so that's a clear collision). Therefore, after un-setting that (to an empty key value), I finally can again comfortably resize my tmux panes with [CTRL]-[b], [+Esc/META]-[DIGIT] (instead of having to use [CTRL]-[b], (the real) [Esc], and then the desired layout [DIGIT]).

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