Answer by Sorpigal for How to find zombie process?

Even though this question is old I thought everyone deserved a more reliable answer:

ps axo pid=,stat=

This will emit two whitespace-delimited columns, the first of which is a PID and the second of which is its state.

I don't think even GNU ps provides a way to filter by state directly, but you can reliably do this with awk

ps axo pid=,stat= | awk '$2~/^Z/ { print }'

You now have a list of PIDs which are zombies. Since you know the state it's no longer necessary to display it, so that can be filtered out.

ps axo pid=,stat= | awk '$2~/^Z/ { print $1 }'

Giving a newline-delimited list of zombie PIDs.

You can now operate on this list with a simple shell loop

for pid in $(ps axo pid=,stat= | awk '$2~/^Z/ { print $1 }') ; do    echo "$pid" # do something interesting heredone

ps is a powerful tool and you don't need to do anything complicated to get process information out of it.

(Meaning of different process states here - https://unix.stackexchange.com/a/18477/121634)