How to use PS, Kill & Nice in Linux to manage processes
- Written by Michael Dudli
- Published in Basics
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Processes in Linux have extreme critical importance as every task and application running on your server is a process and sometimes processes stuck and can cause a system crash so to save your server, you have to identify the stuck process and kill the process before it kills your server and prove to be disastrous for you
To check how many process are running on Linux you can use the top command but ps command with combinations can also give you a good picture
#ps aux
USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND
root 1 0.0 0.2 24188 2120 ? Ss 14:28 0:00 /sbin/init
root 2 0.0 0.0 0 0 ? S 14:28 0:00 [kthreadd]
root 3 0.0 0.0 0 0 ? S 14:28 0:00 [ksoftirqd/0]
root 6 0.0 0.0 0 0 ? S 14:28 0:00 [migration/0]
root 7 0.0 0.0 0 0 ? S 14:28 0:00 [watchdog/0]
root 8 0.0 0.0 0 0 ? S< 14:28 0:00 [cpuset]
root 9 0.0 0.0 0 0 ? S< 14:28 0:00 [khelper]
lets suppose we want to grep a process in all of these processes
#ps aux | grep khelper
This will give you only one process khelper
Now we want to kill the process as it’s stuck so we can use following commands to kill it
#kill 9 (9 is the PID of khelper)
#pkill -9 khelper
#killall khelper
All of these commands will kill khelper in their own way
Now if you want to run a program with a certain value use the command nice. High priority processes are less nice and low priority process are nicer as they consume less resources of server
Let’s say I want to run uptime command with priority 5
#nine –n 5 uptime

Michael Dudli
Cloud Specialist with more than 10 years experience in the Hosting Business.
Website: www.cloudserver24.com