How can I tell whether I'm in a screen?

Question

When using screen in linux, how can I tell if I\'m in a screen or not? I could do exit and I\'ll exit a screen if I was in one, but if I wasn\'t, then I\'ll end

Answer 1

screen -ls can tell you.

Outside screen:

$ screen -ls
There are screens on:
        16954.pts-1.auds916     (Detached)
        242.pts-8.auds916       (Detached)
2 Sockets in /tmp/screens/S-glennj.

Inside a screen:

$ screen -ls
There are screens on:
        16954.pts-1.auds916     (Attached)
        242.pts-8.auds916       (Detached)
2 Sockets in /tmp/screens/S-glennj.