pgrep Command Cheat Sheet

pgrep looks through the currently running processes and lists the process IDs (PIDs) which match the selection criteria. It is safer and easier than ps aux | grep.

Synopsis

pgrep [options] pattern

Basic Usage

Find PID by Name

pgrep sshd
# Output:
# 1050
# 1234

List Name and PID (-l)

Shows the process name alongside the ID.

pgrep -l sshd

List Full Command Line (-a)

Shows the full startup command.

pgrep -a python
# Output:
# 3455 python manage.py runserver

Advanced Filtering

Full Command Search (-f)

By default, pgrep only matches the process name (first 15 chars). Use -f to match against the full argument list.

# Find the PID of the python script "my_worker.py"
pgrep -f "my_worker.py"

By User (-u)

Find processes owned by root.

pgrep -u root sshd

Inverse Match (-v)

Find processes NOT matching criteria.

pgrep -v systemd

Count Matches (-c)

Don't show PIDs, just count how many are running.

pgrep -c nginx

Using with Other Commands

pgrep output is perfect for piping.

# Top for specific processes
top -p $(pgrep -d',' nginx)

Notes

• pkill: pgrep finds them; pkill kills them. They share most flags.
• Exit Code: 0 (One or more matches), 1 (No matches), 2 (Syntax error).