Example Usage of ps Command in Linux

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Example Usage of ps Command in Linux

This guide will take you through various example usage of ps command in Linux/Unix system. ps, an acronym for Processes Status is a utility used to display running processes on Linux/Unix systems system. It reports a snapshot of the current system processes.

Syntax: ps [options]

ps accepts three types of options:

1.UNIX options, which may be grouped and must be preceded by a dash (-)
2. BSD options, which may be grouped and must not be used with a dash.
3. GNU long options, which are preceded by two dashes (–)

Using of ps Command in Linux

1. Display processes associated with the current shell.

When run without any arguments, ps command displays the processes associated with the current shell.

 ps
 PID    TTY        TIME   CMD
1446588 pts/0    00:00:00 bash
1570347 pts/0    00:00:00 ps

By default you will obtain the following information:

  • PID The process ID of the process
  • TTY The name of the terminal session (shell) that the process is running within
  • TIME The amount of CPU time used by the process
  • CMD The name of the command that was entered to create the process

2. To display all processes running on the system, type ps -e or ps -A command.

ps -e
    PID TTY         TIME  CMD
      1 ?        00:00:23 systemd
      2 ?        00:00:00 kthreadd
      3 ?        00:00:00 rcu_gp
      4 ?        00:00:00 rcu_par_gp
      6 ?        00:00:00 kworker/0:0H-kblockd
      8 ?        00:00:00 mm_percpu_wq
      9 ?        00:00:01 ksoftirqd/0
     10 ?        00:00:56 rcu_sched

ps -A 
    PID TTY         TIME  CMD
      1 ?        00:00:23 systemd
      2 ?        00:00:00 kthreadd
      3 ?        00:00:00 rcu_gp
      4 ?        00:00:00 rcu_par_gp
      6 ?        00:00:00 kworker/0:0H-kblockd
      8 ?        00:00:00 mm_percpu_wq
      9 ?        00:00:01 ksoftirqd/0
     10 ?        00:00:56 rcu_sched

3.To display full-format listing, type ps -ef or ps -eF command.

ps -ef
UID          PID    PPID  C STIME TTY         TIME  CMD
root           1       0  0 11:10 ?        00:00:23 /sbin/init splash
root           2       0  0 11:10 ?        00:00:00 [kthreadd]
root           3       2  0 11:10 ?        00:00:00 [rcu_gp]
root           4       2  0 11:10 ?        00:00:00 [rcu_par_gp]
root           6       2  0 11:10 ?        00:00:00 [kworker/0:0H-kblockd]

ps -eF
UID          PID    PPID  C    SZ   RSS PSR STIME TTY         TIME  CMD
root           1       0  0 42347 10916   2 11:10 ?        00:00:23 /sbin/init splash
root           2       0  0     0     0   2 11:10 ?        00:00:00 [kthreadd]
root           3       2  0     0     0   0 11:10 ?        00:00:00 [rcu_gp]
root           4       2  0     0     0   0 11:10 ?        00:00:00 [rcu_par_gp]
root           6       2  0     0     0   0 11:10 ?        00:00:00 [kworker/0:0H-kblockd]

The addition information include:

  • UID The user ID of the process’s owner
  • PPID The PID of the process’s parent process
  • C The amount of processor time utilized by the process
  • RSS How much RAM is utilized at the time the command is output
  • PSR Processor that process is currently assigned to
  • STIME The time that the process started

4. To display long format of the ps output, type ps -efl or ps -eFl command.

ps -efl
F S UID          PID    PPID  C PRI  NI ADDR SZ WCHAN  STIME TTY         TIME  CMD
4 S root           1       0  0  80   0 - 42347 -      11:10 ?        00:00:25 /sbin/init splash
1 S root           2       0  0  80   0 -     0 -      11:10 ?        00:00:00 [kthreadd]
1 I root           3       2  0  60 -20 -     0 -      11:10 ?        00:00:00 [rcu_gp]
1 I root           4       2  0  60 -20 -     0 -      11:10 ?        00:00:00 [rcu_par_gp]

ps -eFl
F S UID          PID    PPID  C PRI  NI ADDR SZ WCHAN    RSS PSR STIME TTY         TIME  CMD
4 S root           1       0  0  80   0 - 42347 -      10916   1 11:10 ?        00:00:25 /sbin/init splash
1 S root           2       0  0  80   0 -     0 -          0   2 11:10 ?        00:00:00 [kthreadd]
1 I root           3       2  0  60 -20 -     0 -          0   0 11:10 ?        00:00:00 [rcu_gp]
1 I root           4       2  0  60 -20 -     0 -          0   0 11:10 ?        00:00:00 [rcu_par_gp]

We obtain the following information:

  • F The flags associated with the process.
  • S The state of the process. This column uses the following codes:
    • D Uninterruptible sleep
    • R Running
    • S Interruptible sleep
    • T Stopped or traced
    • Z Zombie
  • PRI The priority of the process.
  • NI The nice value of the process.
  • ADDR The memory address of the process.
  • SZ The size of the process.
  • WCHAN The name of the kernel function in which the process is sleeping. A dash (–) in this column means the process is currently running.

5.To display all processes in Bsd format, type ps au or ps aux command. 

 ps au
USER         PID %CPU %MEM    VSZ   RSS TTY      STAT START   TIME COMMAND
frank       1975  0.0  0.0 166544  6572 tty2     Ssl+ 09:21   0:00 /usr/lib/gdm3/gdm-x-session --register-session --run-script i3
frank       1978  7.6  0.5 735048 42868 tty2     Sl+  09:21   1:01 /usr/lib/xorg/Xorg vt2 -displayfd 3 -auth /run/user/1000/gdm/Xauthority -background none -noreset -ke
frank       2001  0.0  0.1  35416 12864 tty2     S+   09:21   0:00 i3
  ps aux
USER         PID %CPU %MEM    VSZ   RSS TTY      STAT START   TIME COMMAND
root           1  0.2  0.1 168096 11876 ?        Ss   09:18   0:02 /sbin/init splash
root           2  0.0  0.0      0     0 ?        S    09:18   0:00 [kthreadd]
root           3  0.0  0.0      0     0 ?        I<   09:18   0:00 [rcu_gp]
root           4  0.0  0.0      0     0 ?        I<   09:18   0:00 [rcu_par_gp]

6.To display all processes whose effective user ID (EUID) or name is in the userlist, type ps -fu frank or ps -fu 1000 command.

ps -fu frank
 UID          PID    PPID  C STIME TTY          TIME CMD
frank       1880       1  0 09:21 ?        00:00:00 /lib/systemd/systemd --user
frank       1884    1880  0 09:21 ?        00:00:00 (sd-pam)
frank       1896    1880  1 09:21 ?        00:00:18 /usr/bin/pulseaudio --daemonize=no --log-target=journal
 ps -fu 1000
UID          PID    PPID  C STIME TTY          TIME CMD
frank       1880       1  0 09:21 ?        00:00:00 /lib/systemd/systemd --user
frank       1884    1880  0 09:21 ?        00:00:00 (sd-pam)
frank       1896    1880  1 09:21 ?        00:00:18 /usr/bin/pulseaudio --daemonize=no --log-target=journal

7. To display processes whose real user ID (RUID) or name is in the userlist, type ps -fU frank or ps -fU 1000 command.

ps -fU frank
UID          PID    PPID  C STIME TTY          TIME CMD
frank       1880       1  0 09:21 ?        00:00:00 /lib/systemd/systemd --user
frank       1884    1880  0 09:21 ?        00:00:00 (sd-pam)
frank       1896    1880  1 09:21 ?        00:00:20 /usr/bin/pulseaudio --daemonize=no --log-target=journal

8. To display all processes by real group ID (RGID) or name, type ps -fG dip or ps -fG 30 command.

ps -fG dip
UID          PID    PPID  C STIME TTY          TIME CMD
libvirt+    1376       1  0 09:20 ?        00:00:00 /usr/sbin/dnsmasq --conf-file=/var/lib/libvirt/dnsmasq/default.conf --leasefile-ro --dhcp-script=/usr/lib/libvirt/li
 ps -fG 30
UID          PID    PPID  C STIME TTY          TIME CMD
libvirt+    1376       1  0 09:20 ?        00:00:00 /usr/sbin/dnsmasq --conf-file=/var/lib/libvirt/dnsmasq/default.conf --leasefile-ro --dhcp-script=/usr/lib/libvirt/li
❯ ps -fG dip

9. To display all processes by effective group ID (EGID) or name, type ps -fg dip or ps -fg 30 command.

ps -fg dip
UID          PID    PPID  C STIME TTY          TIME CMD
libvirt+    1376       1  0 09:20 ?        00:00:00 /usr/sbin/dnsmasq --conf-file=/var/lib/libvirt/dnsmasq/default.conf --leasefile-ro --dhcp-script=/usr/lib/libvirt/li

10. To select processes by PID, type ps -fp 3511 command.

ps -fp 3511
UID          PID    PPID  C STIME TTY          TIME CMD
frank       3511       1  0 09:21 pts/0    00:00:00 /usr/bin/zsh

11. To select a processes by PPID, type ps -f --ppid 3890 command.

ps -f --ppid 3890
UID          PID    PPID  C STIME TTY          TIME CMD
frank       4246    3890  0 09:22 ?        00:00:00 /opt/google/chrome/chrome --type=utility --utility-sub-type=storage.mojom.StorageService --field-trial-handle=132069
frank       4430    3890  0 09:22 ?        00:00:18 /opt/google/chrome/chrome --type=renderer --field-trial-handle=13206994095123897317,8220222987148921566,131072 --lan
frank       4432    3890  0 09:22 ?        00:00:01 /opt/google/chrome/chrome --type=renderer --field-trial-handle=13206994095123897317,8220222987148921566,131072 --lan

12. To display ASCII art process tree, type ps -ef --forest command.

ps -ef --forest
root        1856     976  0 09:21 ?        00:00:00  \_ gdm-session-worker [pam/gdm-password]
frank       1975    1856  0 09:21 tty2     00:00:00      \_ /usr/lib/gdm3/gdm-x-session --register-session --run-script i3
frank       1978    1975  6 09:21 tty2     00:05:17          \_ /usr/lib/xorg/Xorg vt2 -displayfd 3 -auth /run/user/1000/gdm/Xauthority -background none -noreset -keept
frank       2001    1975  0 09:21 tty2     00:00:01          \_ i3
frank       2066    2001  0 09:21 ?        00:00:00              \_ /usr/bin/ssh-agent /usr/bin/im-launch i3

13. To display a process tree for a given process, type ps -ef --forest | grep -v grep | grep zsh command.

ps -ef --forest | grep -v grep | grep zsh
frank       3458    3318  0 09:21 pts/0    00:00:10      \_ /usr/bin/zsh
frank       3511       1  0 09:21 pts/0    00:00:00 /usr/bin/zsh
frank       3590       1  0 09:21 pts/0    00:00:00 /usr/bin/zsh
frank       3591       1  0 09:21 pts/0    00:00:00 /usr/bin/zsh

14. To select processes associated with the terminal given in tty list, type ps -t pts/0 commands.

ps -t pts/0
PID TTY          TIME  CMD
3458 pts/0    00:00:12 zsh
3511 pts/0    00:00:00 zsh
3590 pts/0    00:00:00 zsh
3591 pts/0    00:00:00 zsh
3615 pts/0    00:00:00 gitstatusd-linu
292279 pts/0  00:00:00 sudo

15. To select processes whose PID appear in pidlist, type ps -fp 1903,1947,3362 command.

ps -fp 1903,1947,3362
UID          PID    PPID  C STIME TTY          TIME CMD
frank       1903    1880  0 09:21 ?        00:00:00 /usr/bin/dbus-daemon --session --address=systemd: --nofork --nopidfile --systemd-activation --syslog-only
frank       1947    1880  0 09:21 ?        00:00:00 /usr/libexec/goa-identity-service
frank       3362    1880  0 09:21 ?        00:00:00 /usr/libexec/at-spi-bus-launcher

16. To display PID of a given process name, type ps -C compton -o pid= command.

ps -C compton -o pid=
 2095

17. To display NAME of a given PID, type ps -q 2095 -o comm= command.

ps -q 2095 -o comm=
compton

18. To dispaly PID,PPID,User name and Command of a process, type ps -eo pid,ppid,user,cmd command.

ps -eo pid,ppid,user,cmd
PID     PPID  USER    CMD
1982       2 root     [krfcommd]
2001    1975 frank    i3
2066    2001 frank    /usr/bin/ssh-agent /usr/bin/im-launch i3
2084       1 frank    /bin/sh -c dunst 
2087    2084 frank    dunst
2095       1 frank    compton
2099       1 frank    /bin/sh -c i3bar  --bar_id=bar-0 --socket="/run/user/1000/i3/ipc-socket.2001"

19. To display a specific process by its name, type ps -C zsh command.

ps -C zsh
PID TTY          TIME  CMD
3458 pts/0    00:00:12 zsh
3511 pts/0    00:00:00 zsh
3590 pts/0    00:00:00 zsh
3591 pts/0    00:00:00 zsh

20. To display execution time of a process, type ps -eo comm,etime,user | grep terminator command.

ps -eo comm,etime,user | grep terminator
terminator         02:26:03 frank

21. To display security context (for SELinux), type ps -eM or ps -e --context command. 

ps -eM
LABEL                               PID TTY          TIME CMD
unconfined                            1 ?        00:00:10 systemd
unconfined                            2 ?        00:00:00 kthreadd
unconfined                            3 ?        00:00:00 rcu_gp
ps -e --context 
PID CONTEXT                         COMMAND
1 unconfined                      /sbin/init splash
2 unconfined                      [kthreadd]
3 unconfined                      [rcu_gp]
4 unconfined                      [rcu_par_gp]

This is all about our guide on the usage of ps Command in Linux/Unix system.

Reference

For more information about ps command feel free to check man and info ps pages respectively. If you have other ps command usage examples drop a comment.

man ps
info ps

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