$ Linux Command

Processes

pgrep

Find process IDs by name or attributes.

processpidsearchname

Additional Notes

pgrep searches the running process table and prints process IDs that match a name, full command line, user, parent process, terminal, or other attributes. It is cleaner than combining ps and grep by hand.

Use pgrep before sending signals with pkill or kill. It helps verify exactly which processes a pattern matches.

Syntax

pgrep [options] pattern

Parameters

  • pattern: Process name pattern to match. By default, this matches the process name, not always the full command line.
  • options: Matching and output controls.
  • user: User name or UID used with -u or -U.

Common Options

  • -a: Show PID and command line.
  • -f: Match against the full command line.
  • -l: Show PID and process name.
  • -u USER: Match processes whose effective user is USER.
  • -U USER: Match processes whose real user is USER.
  • -x: Match the exact process name.
  • -n: Show only the newest matching process.
  • -o: Show only the oldest matching process.
  • -P PID: Match children of a parent process.

Examples

pgrep ssh

Print PIDs for processes named like ssh.

pgrep -af nginx

Match the full command line and show commands.

pgrep -u deploy -a python

Find Python processes owned by deploy.

pgrep -x systemd

Match the exact process name.

Practical Notes

  • Use pgrep -af PATTERN when testing patterns for pkill -f.
  • Process names can be shorter than full command lines; use -f when arguments matter.
  • Scripts should handle the case where pgrep returns no matches.