Journal Control
journalctl
May be used to query the contents of the systemd(1) journal as written by systemd-journald.service(8).
Use
journalctl -xe show last 1000 messages in a pager
journalctl -f follow latest messages
journalctl -t sshd show messages of a particular service
Useful Flags
-p <priority> show messages with $priority and above only
-b <priority> show messages since last boot only