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Mac OS X, Terminal, Screen, and Ctrl-Arrow Keys

I have had a number of frustrations since I started at Facebook in adapting to the quirks of Mac OS X. I have been in Windows-land for so long that I consider its quirks normal, so figuring out the quirks of OS X has at times been frustrating. Nevertheless, I think I am making good progress.

I am using GNU screen while logged in to linux machines extensively during work, so I invested a little time in setting up a good screenrc. Afterwards, I noticed that I was unable to get the screens to switch using ctrl-left and ctrl-right the same way I would be able to from a Windows machine.

After being frustrated with trying to get Terminal to send the right control characters, and getting screen to recognize them using bindkey, I took a step back and found a solution that actually works. Despite its failings at behaving like PuTTY in every respect, Terminal does offer a lot of customizations, including the ability to change what control characters get sent when you press control-left and control-right, for example. So instead of trying to divine the right bindkey option for Mac OS X (which no one seems to have succeeded at as far as I can tell), I took another approach:

I told Terminal to send “ctrl-a p” (\001ap) for ctrl-left, and “ctrl-a n” (\001n) for ctrl-right. This makes hitting those keys the equivalent of going to the previous and next screens manually, but without the manual part. Of course, if you use a different control character for your screen, you will want to use that instead of ctrl-a as I did, but this finally got screen to behave the way I wanted, which makes me quite happy.

For reference, my screenrc looks like this right now:

vbell off
autodetach on
startup_message off
defscrollback 10000

hardstatus alwayslastline
hardstatus string '%{= kG}%-Lw%{= kW}%50> %n*%f %t%{= kG}%+Lw%< %{= kG}'

8 Responses to “Mac OS X, Terminal, Screen, and Ctrl-Arrow Keys”

  1. Vince Says:

    Oh Ryan. You and your use of screen….

  2. Spencer Says:

    Use iTerm (http://iterm.sourceforge.net). It is >>Terminal.

    Also, a good idea is to update the X11 system, which has to be done manually at http://xquartz.macosforge.org. While apple develops and maintains the project, for some reason X11 isn’t updated with the rest of the apple system.

  3. Spencer Says:

    Btw, if you’re on snow leopard you have the latest version of x11 already. Nevermind~

  4. RJ Ryan Says:

    This is what I had to do to my screenrc to get it working without your trick:

    bindkey “33[5D” prev
    bindkey “33[5C” next
    bindkey “33[2D” prev
    bindkey “33[2C” next

  5. RJ Ryan Says:

    (Doh! my previous comment had its backslash-0’s eaten — trying again with double-backslashes)

    This is what I had to do to my screenrc to get it working without your trick:

    bindkey “\33[5D” prev
    bindkey “\33[5C” next
    bindkey “\33[2D” prev
    bindkey “\33[2C” next

  6. RJ Ryan Says:

    Well, ok I’m having escaping trouble here:

    Prefix the 33 in all cases above with backslash zero.

  7. Ryan McElroy Says:

    Oh, silly WordPress can’t handle \0 in comments? Sad.

  8. Rensa Says:

    Thanks so much—I’m setting up a .screenrc for my work servers, where I don’t think I can use tmux, and this is a blessing.

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