Hi,

> -----Original Message-----
> From: zsh-users-request@zsh.org <zsh-users-request@zsh.org> On Behalf Of
> zzapper
> Sent: Freitag, 1. Oktober 2021 18:55
> Thanks for both answers
>
> this seems to be what I need
>
> if pgrep "tmux" > /dev/null ; then echo "Running" ; else echo "Stopped" ;
> fi

That will only work if you're the only user of the system, who has tmux 
processes.  On multi-user machine with several tmux instances running for 
different users, pgrep tmux will also match those.

Kind regards,
        -michael