aeolist@ubuntu:~$ screen -r
There are several suitable screens on:
        5538.irc        (Detached)
Type "screen [-d] -r [pid.]tty.host" to resume one of them.
aeolist@ubuntu:~$ ps -A | grep screen
 5538 ?        00:00:02 screen
17810 pts/0    00:00:00 screen
24777 ?        00:00:00 screen
26065 ?        00:00:00 screen
aeolist@ubuntu:~$ ps -A | grep irssi
 5539 pts/1    00:00:03 irssi