Cannot break running process in Terminal 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.
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).