Control the systemd system and service manager. More information: https://www.freedesktop.org/software/systemd/man/systemctl.html.
systemctl status
systemctl --failed
systemctl start|stop|restart|reload|status unit
systemctl enable|disable unit
systemctl daemon-reload
systemctl is-active|is-enabled|is-failed unit
systemctl list-units --type=service|socket|automount --state=failed|running
systemctl cat unit