Resume last screen, if any

Question

Basically i need to have a script that checks if there is a screen running as "serverman". If it exists, then resume it, otherwise create new.

So i wanted to parse "sceen -ls" and check if there is one called "serverman".

This is "screen -ls" output

There are screens on:
    7423.212        (03/09/14 08:48:58)     (Detached)
    7411.1as        (03/09/14 08:48:49)     (Detached)
2 Sockets in /var/run/screen/S-root.

I was tinking to a command that could parse it trough piping and search for "serverman" word. And if any set isalreadyrunning=1, else set it to 0, but i don't know what command to use and how to use, do you?

Answer 1

You can already do this with existing screen options without explicitly checking for a named session. screen -D -R serverman will attach to serverman if exists, but will create it and attach to it if not.

Answer 2

I paste a working script for tmux, as apparently I have old screen on my old MacBook that gives different output. You should be able to modify it easily (but I would advice to switch to tmux, it's way better)

# created sessions with
# tmux new -s hello
# tmux new -s world

SEARCHING="hello"

found_session=$(tmux ls 2> /dev/null | perl -ne "if (/(^${SEARCHING}):/) {print \"\$1\"}" | head -n1)

if [ -z "$found_session" ]; then
    echo Session not found, creating new.
    tmux new -s $SEARCHING
else
    echo Found $found_session, attaching.
    tmux a -t $found_session
fi