How To Monitor / Manage Processes In Linux System | ps,top, nice, renice

 

Below are some important commands which can be used to check the processes in Linux  system.

1: PS command : ps stand for processes in Linux. you can use this command with various options to check the processes running in the system & manage them. Below are some common use of ps command.

a) If you run only 'ps' command it will show only current executed process by you.

b) If  you want to check every single process running  under the system 

 

$'ps -e'

You can use 'ps -ef , ps -eF , ps -ely' options to get detailed information about all processes.

 

c) If you want to check all running process in  hierarchy format. 

 

$ ps -ejH or ps -axjf

d) If you want to check process with their exact path location . 

 

$ 'ps -eLf' 

e) To see every process running as root in user format , run command

$ ps -U root -u root u

f) To see every process as user defined options. 

$ ps eo pid, tid, class, rtprio, ni, pri, pcpu, stat, comm

put options given with command to see related output.

g) To see the process id of any specific process with 'ps' command

$ ps -C sshd -o pid=

you can see the process name with the process id 

$ ps -q 1806 -o comm=

2:TOP Command : 

top displays the running processes in the monitoring format with current status. just type 'top' command to see the process current status. It will also show you the current ram , cpu , utilization as well as users login numbers , processes states numbers.

type  'h' for help or 'q' any time to quit.

some important options while using top command

z > for color 

E/e > get summary in human readable format

l > show load average row

t > show task average row

m > show memory average row

0 > to hide  zero values

F/f > add or remove fields in top column

L > find specific process

& > find again

V > forest view/hierarchy

r> renice process 

k > kill the process

U/u > specific user processes

3) Nice/Renice commands:

nice command is use to set the priority of any process while executing them. for example to run 'top' command with high priority run nice as :

nice -n -20 top

This will start top command with high priority. nice value range is -20 to +20. where -20 is highest and +20 is lowest. you can set any priority between these two values.

renice command is use to change the priority of already running process in system  , you can use with pid ,gid , userid

renice -n 'priority_number' -p | -u | -g