---
title: systemd
kind: note
description: Linux init system
words: 178
readingMinutes: 1
created: '2024-01-30T00:00:00.000Z'
updated: '2026-06-29T20:34:03+02:00'
website: https://systemd.io/
---
## Link

<https://systemd.io/>

[Linux](/notes/linux) init system (base system component)
## Resources
- [Service unit configuration](https://www.freedesktop.org/software/systemd/man/latest/systemd.service.html)
- [Timers](https://wiki.archlinux.org/title/Systemd/Timers)
- [systemd user services](https://www.unixsysadmin.com/systemd-user-services/)
- [systemd by example](https://systemd-by-example.com/)
  > The playground allows you to learn about systemd interactively, right from your browser! Create examples without the danger of breaking your system, and without being distracted by hundreds of unrelated unit files.
- [Rethinking PID 1](https://0pointer.de/blog/projects/systemd.html) - systemd announcement
### journald
- [Introduction to the Systemd journal](https://linuxconfig.org/introduction-to-the-systemd-journal)
### nspawn
- [ArchWiki](https://wiki.archlinux.org/title/Systemd-nspawn)
- [Debian Wiki](https://wiki.debian.org/nspawn)
- [Fedora Magazine](https://fedoramagazine.org/container-technologies-fedora-systemd-nspawn/) (❗ dated article written <span class="dead-link">2016-06-28</span>)
- [Jip-Hop/jailmaker](https://github.com/Jip-Hop/jailmaker) - persistent [Linux](/notes/linux) 'jails' on [TrueNAS](/notes/truenas) to install [software](/notes/software) (<span class="dead-link">k3s</span>, [docker](/notes/docker), <span class="dead-link">portainer</span>, [podman](/notes/podman), etc.) with full access to all files via bind mounts thanks to systemd-nspawn
## FAQ
### List enabled timers and their next run date
```shell
systemctl list-timers
```
### Which user services are running?
To find out which **systemd user units** are running, you can use the following command:
```shell
systemctl --user list-units --type=service --state=running
```
Explanation of the command:
- `--user`: Checks the user-specific systemd instance.
- `list-units`: Lists the currently active units.
- `--type=service`: Filters the output to only include services. You can omit this or replace it with another type (e.g., `--type=socket`).
- `--state=running`: Limits the output to only the running units.