Screen -X

I found here a nice use of screen I didn't know about:

screen -X stuff

You can send a sequence of chars to any screen!,

example

screen -S 9962.pts-0.ursa -p 4 -X stuff 'ls^M'

Side note: I knew the ESC * and the ESC ESC meaning on bash, but I didn't know the ESC . That's useful!.