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Linux ps

The ps command is used to view currently running processes on the system. It helps us to determine which process is doing what in our system, how much memory it is using, how much CPU space it occupies, user ID, command name, etc .

The ps command may display different results for different systems because it displays information about the currently running process of a system.

Syntax:

Look at the above snapshot, 4 columns are displayed as the output.

• PID is the process ID of running command
• TTY is the type of terminal where current command is running
• TIME tells how much time is used by CPU to run the process
• CMD is current command

ps command supports 3 types of usage syntax style

• Unix, may be grouped and preceded by hyphen
• BSD, may be grouped but not preceded by hyphen
• GNU, long options and preceded by double hyphens

Options

Option	Function
ps -ef/ ps -aux	List currently running process in full format
ps -ax	List currently running process
ps -u <username>	List process for specific user
ps -C <command>	List process for given command
ps -p <PID>	List process with given PID
ps -ppid <PPID>	List process with given ppid
pstree	Show process in hierarchy
ps -L	List all threads for a particular process
ps –sort pmem	Find memory leak
ps -eo	Show security information
ps -U root -u root u	Show process running by root