There is a lot of helpful information about screen out there, but I haven’t found anything about this. I don’t want to “forget” any screen sessions, so I’d like to be notified when I log into a box and there are screens running for me. Obviously, there is screen -ls, but it needs to be wrapped in a bit logic so that it doesn’t annoy when there is no screen running or even installed.

After perusing the screen man page a little, I came up with this for .bash_profile or .zprofile:

if which screen >/dev/null; then
    screen -q -ls
    if [ $? -ge 10 ]; then
        screen -ls

The trick is that -q in conjuction with -ls gives you exit codes about the current status of screen.

Here is an example of how this looks in practice:

~$ ssh host
Last login: Fri Feb 13 11:30:10 2015 from
There is a screen on:
        31572.pts-0.foobar      (2015-02-15 13.03.21)   (Detached)
1 Socket in /var/run/screen/S-peter.