ps command (process status) will display snapshot information of all active processes.
Syntax: ps [options]
How to display all the processes running in the system?
Use “ps aux”, as shown below.
# ps aux | more USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND root 1 0.0 0.0 2044 588 ? Ss Jun27 0:00 init [5] apache 31186 0.0 1.6 23736 17556 ? S Jul26 0:40 /usr/local/apache2/bin/httpd apache 31187 0.0 1.3 20640 14444 ? S Jul26 0:37 /usr/local/apache2/bin/httpd
You can also use “ps -ef | more”, to get a similar output
Print the Process Tree
You can use either ps axuf or ps –ejH to display processes in a tree format. The tree structure will help to visualize the process and it’s parent process immediately. For clarity purpose, few columns have been cut-off in the output below.
# ps axuf root Oct14 0:00 /opt/VRTSralus/bin/beremote root Oct14 0:00 \_ /opt/VRTSralus/bin/beremote root Oct14 0:00 \_ /opt/VRTSralus/bin/beremote root Oct14 0:00 \_ /opt/VRTSralus/bin/beremote root Oct14 0:01 \_ /opt/VRTSralus/bin/beremote root Oct 14 0:00 \_ /opt/VRTSralus/bin/beremote root Dec03 0:01 /usr/local/sbin/sshd root Dec22 1:08 /usr/local/sbin/sshd root 23:35 0:00 \_ /usr/local/sbin/sshd 511 23:35 0:00 \_ -bash 511 \_ ps axuf
Note: You can also use pstree command to display process in tree structure.
View Processes Owned by a Particular User
The following command displays all the process owned by Linux user-name: oracle.
$ ps U oracle PID TTY STAT TIME COMMAND 5014 ? Ss 0:01 /oracle/bin/tnslsnr 7124 ? Ss 0:00 ora_q002_med 8206 ? Ss 0:00 ora_cjq0_med 8852 ? Ss 0:01 ora_pmon_med 8854 ? Ss 0:00 ora_psp0_med 8911 ? Ss 0:02 oraclemed (LOCAL=NO)
View Processes Owned by Current User
Following command displays all the process owned by the current user.
$ ps U $USER PID TTY STAT TIME COMMAND 10329 ? S 0:00 sshd: ramesh@pts/1,pts/2 10330 pts/1 Ss 0:00 -bash 10354 pts/2 Ss+ 0:00 -bash 10530 pts/1 R+ 0:00 ps U ramesh