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.
Tmux – Option Key Not Working as Meta in macOS
macososx liontmux
Related Solutions
After plowing through the man pages it turns out tmux has an option for this. The following in ~/.tmux.conf fixes the delay problem:
set -sg escape-time 0
You have to restart your tmux server or reload your config for this to take effect. To do this, issue source-file ~/.tmux.conf from the tmux prompt.
To fix iTerm 2's behavior, go to Preferences > Profiles > Keys and set the left (and/or right) Option key to act as "Normal":
That way you'll be able to enter key combinations for umlauts, accents, etc.
If you have several profiles defined, you'll have to make the change for each one.
Best Answer
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: