How to use ps command in Linux with example of uses

ps command (process status command) is used display list of running process on your linux system along with their PID’s (process identification numbers).

Syntax

ps

Running this command displays processes for current shell along with PID number, TTY (Terminal type), time and command.

Display all running processes

To display all running process use following command

Syntax

ps -A

OR

ps –e

Display all running processes with detailed information

To get a full list of running processes use the following command

Syntax

ps -ef

-e as we have already mentioned shows all running programs and –f will show full details.

User ID is the person who initiated the command. The PID is the process ID of the command and PPID is the parent process that started the command.

The C column shows the number of children of process. The STime is the start time for the process. The TTY is the terminal, the time is the amount of time it took to run and command is the command which was run.


Display processes by real group ID or name

To display all processes owned by a group (real group ID or name) use -G or -g switch

Syntax

To display process owned by name of group

ps -G group_name

and

To display process on basis of Group ID number

ps -u group_ID

Display processes by Process ID

Process list can be displayed by using process ID details, switch used in this case is -p.

Syntax

ps -p process_id

Display processes by Process ID list

Process list can also be displayed by using list process ID details, switch used in this case is -p. All process ID’s are separated by comma’s

Syntax

ps -p process_id_list

Find process name by its process ID

To find process name using its ID use following command

Syntax

ps -p [process_ID] -o comm=

Display processes by terminal

To display process by terminal details using switch -t

Syntax

ps -t [terminal_details]

Display processes child and parent by process name

A process can be selected using -C switch, it will also display all its child process

ps -C [process_name}



Display processes tree

Process tree displays how processes are linked to each other. Parent of a process is either a process with given PID or it will be init.

ps -forest

and

In case you want to view process tree for a particular process use command

ps -f -forest -C apache