:PROPERTIES:
:ID:       941e0a85-1bb4-45be-a729-1b577c7ee317
:END:
#+title: Command line: journalctl
#+date: "2021-05-20 23:07:39 +08:00"
#+date_modified: "2021-07-20 23:31:16 +08:00"
#+language: en
#+property: header-args  :results none


The logging daemon of systemd.
(Ooooh...)
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= - show the logs starting from boot time
- =-e, --pager-end= - go to the end of the logs
- =-f, --follow= - watch the logs
- =--user-unit= - show logs from a user unit
- =-u, --unit [UNIT]= - show the logs of a system unit
- =--vacuum-time [TIMESPAN]= - delete logs older than the specified timespan [fn:: View =systemd.time.5= for more information.]
- =-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

#+begin_src
journalctl --user-unit borgbackup.service -fb
#+end_src


** Delete the logs older than a month

#+begin_src
journalctl --vacuum-time=1m
#+end_src


** View the latest logs with helpful messages

#+begin_src
journalctl -xe
#+end_src