This has been killing me for a while. In macOS terminal, I cannot break a process. I've tried every combination of keys. Command. doesn't work.

For example, if I open a screen session with a serial device. It works fine but I cannot exit screen. The only way to kill it is by using Activity Monitor.

stty-a shows that most things are bound to ^ "key", but this Control + "key" doesn't do anything either.

  • I suppose you tried cntrl-C?
    – Natsfan
    Dec 17, 2018 at 15:50

2 Answers 2


To exit screen you press ControlA followed by Control\.

You can find a comprehensive list of all the default key bindings in the man page (man screen).

  • That still doesn't work. Conrtol + a highlights everything in terminal, Ctrl + Shift + a brings me to the top of where sceen was started, but doesn't stop it. and Is there anything else I could be missing?
    – salad
    Dec 16, 2018 at 18:47
  • Have you remapped keybindings? I have tested on 3 different versions of macOS and none will highlight everything when you press Ctrl-A in Terminal. Also, it's supposed to be in screen that you press Ctrl-A.
    – Allan
    Dec 16, 2018 at 20:30
  • I am not familiar with the screen command. I noticed that command + a highlights everything. control + a after the command + a gets rid of the highlighting. Dec 17, 2018 at 22:00
  • 1
    You keep saying Command. It's Control. It's the key directly to the right of fn and directly to the left of Option which is to the left of Command.(And yes, Command-A does select everything; you're hitting the wrong key!)
    – Allan
    Dec 17, 2018 at 22:04

I found control + a d existd from the screen command. see man screen


  • 1
    Control-A, d detaches the current screen meaning your process continues to run in screen. The same but with a capital D detaches and logs out. Quit is Control-A, Control-\ per the man page
    – Allan
    Dec 17, 2018 at 22:46

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