UNIX screen command

I have a mental block when it comes to the UNIX command 'screen' so this is a short reminder for me.

In a UNIX shell run 'screen' to create a new session. In this you might want to run a long job.

To exit from a screen session, destroying that session in the process, type 'exit'.

To detach from the session, leaving it running, type 'Ctrl-a d'

To return to a running 'screen' session from a top level shell, type 'screen -x'. This will list all running sessions and identify each with a PID number.

To return to a specific session, when you only have one running, type 'screen -r'.

To return to a session when more than one are running add the PID to the command, e.g. 'screen -r 123'.