Services (systemctl)

systemctl stop apache2
systemctl start
systemctl 

Logs (journalctl)

Read entries from specific unit

journalctl -u apache.service

Read entries since boot

journalctl --boot

Tail the journal

journalctl -f
journalctl -u apache.service -f

Control

systemctl reboot
systemctl halt
systemctl resume
systemctl emergency  # Put in emergency mode
systemctl default    # Exit emergency mode