journalctl [OPTIONS...] [MATCHES...]

Query the journal.

Filtering options:
  -u --unit UNIT             Show logs from the specified unit
                             (the ".service" suffix is optional)

Output control options:
  -x --catalog               Add message explanations where available
  -e --pager-end             Immediately jump to the end in the pager
     --no-pager              Do not pipe output into a pager

Commands:
  -h --help                  Show this help text

Without -u, messages from all units are printed. The short form
"journalctl -xeu UNIT" is the usual way to see why a service failed to start.

See the journalctl(1) man page for details.
(GreenRay AIO simulates the commands and options listed above.)
