In UNIX and Linux Operating System, Zombie processes also known as defunct processes, are those which are still running after the complete execution of the process but it still remains in the process table. In this tutorial, we will learn how to check and kill Zombie processes in CentOS 8.
How to find zombie/defunct processes in CentOS
To view Zombie or Defunct processes open up the terminal and use the following command:
# ps aux | grep “defunct”
How many Zombie Processes are running?
To view how many Zombie processes are running, you can use the following commands.
# ps aux | awk {'print $8'}|grep -c Z
# ps aux | awk '{ print $8 " " $2 }' | grep -wc Z
# ps aux | awk {'print $8'}|grep Z|wc -l
List the Process ID of Zombie Process
To list down the process ID of the Zombie processes, use the following command:
# ps aux | awk '{ print $8 " " $2 }' | grep -w Z
To kill the Zombie process use the following command with the process id, it will remove the Zombie process running on your server. For this use the following command.
# kill -9 <PID>
Conclusion
In this tutorial, we learned how to display the Zombie process and their process IDs and how to kill them.