screen -ls	list screen sessions
screen -r -x	another user can re-attach
C-A M	monitor window for output
C-A _	monitor window for silence
C-A a	send C-a through screen to the application
C-A "	window list
C-A [	copy mode, also scrollback
	<space> to mark begin, and end.
C-A ]	paste
C-A N	Next window
C-A P	Previous window