systemd-run

Overview

systemd-run creates transient units on the fly: one-shot commands, background services, or temporary timers without writing unit files. Ideal for resource-limited jobs, ad-hoc schedules, and testing cgroup settings.

Syntax

systemd-run [options] command [args...]
systemd-run --user [options] command...

Common Options

Option	Description
--unit=name	Name the transient unit
--property=… / -p	Set unit properties (CPUQuota=, MemoryMax=, …)
--timer-property=…	For --on-calendar / timers
--on-calendar=	Schedule like a timer
--on-active=	Run after a delay
-t / --pty	PTY for interactive
-P / --pipe	Connect stdin/stdout
--wait	Wait until finish
--collect	Garbage-collect unit after exit
--uid= / --gid=	Run as user/group
--working-directory=	cwd

Safety

• Transient timers/services disappear after reboot (unless you convert to real units).
  
• Resource properties can OOM-kill aggressively — test with --user when possible.
  
• Privileged properties need root.

Examples with Explanations

One-shot with wait

sudo systemd-run --wait --unit=scratch-job \
  /usr/local/bin/backup.sh
systemctl status scratch-job

CPU/memory limits

sudo systemd-run -p CPUQuota=50% -p MemoryMax=512M --unit=heavy \
  --wait /usr/local/bin/encode.sh

Transient timer

sudo systemd-run --on-calendar='*-*-* 03:00:00' --unit=nightly-backup \
  /usr/local/bin/backup.sh
systemctl list-timers | grep nightly

User scope

systemd-run --user --on-active=10min --notify-me \
  notify-send 'Timer fired'

Interactive shell in a scope

systemd-run --pty --same-dir --wait --collect bash

Related Commands

• systemctl — manage the resulting unit
  
• systemd-analyze — calendar expression help
  
• cron / at — classic scheduling
  
• nice / ionice / systemd-cgtop — resource control neighbors

Additional Resources

• man systemd-run
  
• man systemd.timer
  
• man systemd.resource-control