The pgrep command searches running processes and prints matching PIDs.

It is safer and cleaner than parsing ps output with grep in many cases.

Overview

You can match by:

• Process name
• Full command line
• User
• Parent PID
• Terminal

Syntax

pgrep [options] pattern

Command Quick Reference

Command	Purpose
pgrep nginx	Find PIDs with name matching nginx
pgrep -x nginx	Exact name match
pgrep -f "python app.py"	Match full command line
pgrep -u root	Match processes owned by root
pgrep -af nginx	Show PID and full command

Core Workflows

Find PID by Name

pgrep sshd
pgrep -x sshd

Match Full Command Line

pgrep -f "node server.js"

Include Process Details

pgrep -af nginx

This prints PID and command line, which helps validate matches.

Restrict by User

pgrep -u www-data -af php-fpm

Useful Options

Option	Meaning
-f	Match against full command line
-x	Require exact process name match
-a	Print full command line with PID
-u	Match by effective user ID/name
-P	Match by parent PID
-n	Only newest matching process
-o	Only oldest matching process

Examples

pgrep -af nginx
pgrep -u root sshd
pgrep -n -f "python worker.py"

Troubleshooting

Too Many Matches

Tighten criteria with -x, -u, or a more specific -f pattern.

No Matches Found

1. Confirm process is running with ps aux.
2. Try -f if command name differs from executable name.
3. Check user context with -u.

Best Practices

1. Prefer pgrep over ps | grep in scripts.
2. Use -a when validating patterns interactively.
3. Combine with kill only after confirming the matched command lines.
4. Use -x for exact service names where possible.

Related Commands

• pkill: Signal matching processes directly
• ps: Inspect process table details
• kill: Signal specific PIDs