Frequently asked questions for systemd
In this section we collect all frequently asked questions about systemd. Do you have a question or one that really should be listed here? Share your feedback. Thanks for your contribution!
How to check if 'systemctl daemon-reload' is needed
When systemd units are changed, a 'systemctl daemon-reload' might be needed. Need to know if this is the case? Let's test for that.
How to check if systemd is being used or active
Learn how to quickly confirm that systemd is being used as your system and service manager.
How to disable a systemd unit with systemctl
Want to disable a service or specific systemd unit? Use systemctl to configure units and disable it on boot or completely.
How to disable the background color of run0
Learn how to disable the change of the background color when using run0.
How to limit the disk usage of the systemd journal
Learn how to define the maximum size that the systemd journal daemon may use for storing journals.
How to override the settings of a systemd unit
The systemctl command can be used to override settings of a systemd unit, like a service.
How to reload the systemd configuration
How can systemd be instructed to reload its configuration?
How to schedule a periodic task with systemd
Schedule a repeating task via systemd by using a timer. Learn how to configure and use it.
How to see all active systemd units of one type
The systemctl command can be used to show all active systemd units of one particular type with the --type option.
How to see all enabled services with systemctl
The systemctl command can be used to show all service units and filter those that are enabled.
How to see all masked units with systemctl
Want to find all masked unit files? In this article we show how to do this with systemctl and query those units.
How to see kernel messages with journalctl
Learn how to show all kernel events by using journalctl and filter out the kernel entries in the journal.
How to see logging for a specific unit or service
Limit the number of log entries from the systemd journal by filtering journalctl output by unit.
How to see memory usage of a service with systemctl?
The systemctl command can be used to show the memory usage of a service managed by systemd.
How to see new log entries automatically with journalctl
Learn how to continuously show new log entries with journalctl like the tail -f command.
How to see only recent journal entries
Learn how to filter journal entries by specifying a date or time interval.
How to see only running services with systemctl
The systemctl command can be used to filter its output and only show all running services.
How to see the active settings of a systemd unit
The systemctl command can be used to show the settings of a systemd unit, like a service.
How to see the available systemd unit types
The systemctl command can be used to show all available systemd unit types.
How to see the dependencies of a systemd unit
The systemctl command has the list-dependencies option to show dependencies between units. But there are more options to query a little bit more information.
How to see the last X lines with journalctl
Limit the output from journalctl by defining the number of lines you want to see.
How to see the size of the systemd journal
Summary
The journalctl command can be used to show the journal. By using the --disk-usage option, the size of the journal is displayed. This includes the archived and active journal files. When the journal is using too much disk space, consider performing a vacuum task. Usage Showing the disk usage is quick and easy. # journalctl --disk-usage Archived and active journals take up 56.0M in the file system. Does the journal take up too much space?
How to see the time synchronization details with timedatectl
Show time synchronization details with the systemd timedatectl command and related subcommands.
How to see which syscalls are part of a systemd syscall filter set
Learn how to see what syscalls are part of a particular syscall filter set in systemd.
How to show failed units with systemctl
Want to check the system for failed systemd units? In this article we show how to do this with systemctl and query the units with a failure state.
How to show the systemd machine ID
Find the machine ID that was generated by systemd.
How to start and enable a unit with systemctl
Combine the start and enable command when using systemctl to get a unit like a service started at boot and right away.
How to use systemctl edit to change a service?
Learn how to edit an existing systemd service unit with the systemctl edit command.
What does systemctl daemon-reload do?
When making changes to systemd unit files, you may need to use systemctl daemon-reload. This article explains what happens next.
What is a masked systemd unit?
What does it mean when a systemd unit is masked? Learn about this state.
What is a systemd unit?
Learn more about systemd units and what they do.
What is systemd?
Learn what systemd is and the main components of this system and service manager.
What is the difference between systemctl disable and systemctl mask?
Want to disable a service, but wondering the difference between systemctl disable and systemctl mask? This article shows the differences between the two.