Killing a Zombie Process

Question

How to kill a zombie process?

If the zombie is a dead process (already killed), how I remove it from the output of ps aux?

root@OpenWrt:~# anyprogramd &
root@OpenWrt:~# ps aux | grep anyprogram
 1163 root      2552 S    anyprogramd
 1167 root      2552 S    anyprogramd
 1169 root      2552 S    anyprogramd
 1170 root      2552 S    anyprogramd
10101 root       944 S    grep anyprogram
root@OpenWrt:~# pidof anyprogramd
1170 1169 1167 1163
root@OpenWrt:~# kill -9 1170 1169 1167 1163
root@OpenWrt:~# ps aux |grep anyprogram
 1163 root         0 Z    [cwmpd]
root@OpenWrt:~# kill -9 1163
root@OpenWrt:~# ps aux |grep anyprogram
 1163 root         0 Z    [cwmpd]

Answer 1

You can clean up a zombie process by killing its parent process. Try this;

kill -HUP $(ps -A -ostat,ppid | grep -e '[zZ]'| awk '{ print $2 }')