Following Logs
journalctl -f
Display logs from the current/last boot
journalctl -b
journalctl -b -1
List boots
journalctl --list-boots
Filter by unit. Unit names from systemd. Multiple unit possible.
journalctl -u nginx.service -u php-fpm.service
Displaying Kernel Messages like dmesg
journalctl -k
Filter by priority
journalctl -p err -b
Persistant logs
/etc/systemd/journald.conf
[Journal]
Storage=persistent