journalctl Reference

Date: [26th Apr 2025]
Categories: [Linux]

Use with sudo to ensure seeing all records.

Display a table of boot records

journalctl --list-boots

Show log of specific boot

journalctl -b [-n] (n is boot number; current boot if omitted)

Show log by date ranges

journalctl --since [now, yesterday, today, tomorrow]
journalctl --since YYYY-MM-DD [--until YYYY-MM-DD]
journalctl --since "20days ago"

(check the man page for systemd.time for date string syntax)

Filter by service or priority

journalctl -u some.service
journalctl -p [priority] (crit, err, info, etc.)

Other options

journalctl -k (kernel messages)
journalctl -r (reverse order)
journalctl -n15 (number of lines to show)
journalctl --no-pager (output full record without "less")
journalctl -f (follow log; like "tail -f")