wiki/cli.journalctl.org

Command line: journalctl

• Options
• Examples
  • Watch the logs from a specific unit at boot time
  • Delete the logs older than a month
  • View the latest logs with helpful messages
  • Get the logs of a service unit from 2 boots ago

The logging daemon of systemd (see systemd-journald). Not only it can view your logs, you can ask to view specific logs and delete some of them.

For more information, see journalctl.1 manual page.

Options

• -b, --boot [ID][+OFFSET] shows the logs starting from given boot time (or current boot if empty).
• -e, --pager-end to go to the end of the logs.
• -f, --follow watches the logs.
• -k, --dmesg prints the logs from the kernel.
• --list-boots prints a list of boots useful for knowing the boot logs from -b.
• --user-unit shows logs from a user unit.
• -u, --unit [UNIT] shows the logs of a system unit.
• --vacuum-time [TIMESPAN] deletes logs older than the specified timespan ¹.
• -x, --catalog prints helpful messages such as the documentation URIs.

Examples

This tool is already comprehensive. Needs a comprehensive database of examples to fight against this scope.

Watch the logs from a specific unit at boot time

journalctl --user-unit borgbackup.service -fb

Delete the logs older than a month

journalctl --vacuum-time=1m

View the latest logs with helpful messages

journalctl -xe

Get the logs of a service unit from 2 boots ago

journalctl --boot -2 --user-unit borgbackup@personal-drive.service

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¹

View systemd.time.5 for more information.