If you are using systemd, journalctl will be the command line tool, you need to get log information.
Show Log
journalctl
Verify Log
journalctl --verify
less-like 1000 lines
journalctl -e
Follow the journal
journalctl -f
Show logs from a unit
journalctl -u <unit>
List boots
journalctl --list-boots
Logs from the last boot
journalctl -b -1