So not really the zombie apocalypse but useful. I sometimes get zombie processes with my GNOME desktop and a lot of the GNOME apps won’t restart with a zombie brother hanging around. While sometimes the only resolution to a zombie process is to restart the computer I often find this helps.
cat /proc/1111/status | grep PPid
Where 1111 is the Zombie process number. This will give you the parent process ID (PPid). For GNOME apps this is often the gnome-shell process. Thankfully the GNOME guys allow you to restart this while all is running without losing your entire desktop session so a simple
killall -HUP gnome-shell
will restart the shell and generally kill off the Zombie so you can get back to reading your email or what ever it is you were trying to do much more quickly without the pain of a full session restart 🙂