systemd-run — Run a transient systemd unit

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Runs a command as a transient systemd service or timer with journal logging and resource control.

Basic Information

What is this command?

systemd-run executes a command under systemd without writing a unit file.

Output goes to the journal and systemd features such as CPU or memory limits and timers apply directly.

What problems does it solve?

• Keep one-off job output in the journal.
• Run with CPU or memory limits.
• Schedule a single future run.
• Run detached from the login session.

Key features

Transient service

Starts the command as a background service and returns immediately.

• When to use: When the job must outlive the session
• What you get: A transient unit managed by systemd
• Limitations: The unit name is needed to check status

Resource limits

Set properties to cap CPU or memory use.

• When to use: When a job must not monopolize the host
• What you get: Execution under the given limits
• Limitations: Requires kernel cgroup support

Timer scheduling

Use --on-calendar and related options to schedule the run.

• When to use: One-off or recurring schedules
• What you get: A scheduled timer unit
• Limitations: Timer state must be checked separately

Installation and usage

Check whether it is installed

systemd-run --version

systemctl --version # systemd must be PID 1

Real-world examples

Transient service

Run as a background service.

# Run a command as a transient service
systemd-run --unit=myjob /usr/local/bin/task.sh

With limits

Limit CPU and memory.

# Cap memory and CPU share
systemd-run -p MemoryMax=512M -p CPUQuota=50% /usr/local/bin/task.sh

Scheduled run

Run once tomorrow at 03:00.

# Schedule a single run
systemd-run --on-calendar='*-*-* 03:00:00' /usr/local/bin/task.sh