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To kill a process on Linux, find its process ID (PID) with pgrep -a python or ps aux | grep python, then run kill 12345. That sends SIGTERM, which asks the program to close cleanly. If it is still running after a few seconds, force it with kill -9 12345 (SIGKILL). Use sudo for processes owned by other users, and stop services with systemctl stop rather than kill.

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Before you start

  • Connect with SSH.
  • You can kill your own processes. Processes owned by root or other users need sudo (root can leave it out).
  • If the program is a service (nginx, MariaDB, a game server unit), use sudo systemctl stop name or restart. systemd restarts many killed services automatically. See manage services with systemctl.

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How to find the process ID (PID)

The first number is the PID.

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How to kill a process by PID

1

Ask it to stop

This sends SIGTERM (signal 15). The program can save its work and close.
2

Check it is gone

If only the header line prints, the process has ended.
3

Force it if needed

If it is still running after 5 to 10 seconds:
SIGKILL (signal 9) stops it instantly. The program can’t clean up, so unsaved data is lost.
Use kill -9 as a last resort. A database or game server killed this way can lose recent data or corrupt files; stop those through their own command or systemctl stop. Never kill PID 1 (systemd), sshd while you are connected through it, or processes you don’t recognise on a production server.

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Common signals

Use the name or the number: kill -HUP 1204 and kill -1 1204 are the same. kill -l lists all signals.

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How to kill a process by name

pkill and killall send SIGTERM too; add -9 to force.
Name matching can hit more than you expect. pkill -f matches anywhere in the command line, including other users’ processes (with sudo) and even the shell that runs the command. Always preview first with pgrep -a -f "pattern", check the list, then run pkill with the same pattern.
On AlmaLinux and Rocky Linux, killall comes from the psmisc package: sudo dnf install psmisc.

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What to do if a process won’t die

Check the state with ps -o pid,stat,cmd -p 30043. The STAT column shows D, Z, S (sleeping) or R (running).

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How to check it worked

If nothing matches, you see no process running. If you killed a program to free a port, sudo ss -tlnp 'sport = :8080' should show only the header line.

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Frequently asked questions

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What is the difference between kill, pkill and killall?

kill takes a PID. pkill takes a pattern and matches part of the name (or the full command line with -f). killall matches the exact process name.

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How do I kill all processes of one user?

Run sudo pkill -u alex to send SIGTERM to all of alex’s processes. This also ends their SSH sessions.

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How do I kill a process that is using a port?

Find it with sudo lsof -i :8080 -t (prints only the PID) and kill it: sudo kill $(sudo lsof -i :8080 -t). Check the PID first if it might be a service.

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My server is out of memory and processes keep getting killed. Why?

That is the kernel’s out-of-memory (OOM) killer. See fix out of memory killed processes and check memory usage.

VPS and dedicated server guides

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Monitor resources with htop

Find and kill processes visually.

Find what is using CPU

Track down a busy process.

Manage services with systemctl

Stop services the right way.

Check open ports

Find what holds a port.
Checked against the kill(1), pkill(1) and signal(7) manuals on 4 November 2026; commands tested on Ubuntu 24.04 LTS. Commands can differ on other distributions or releases.

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Last Updated: November 2026