opciones disponibles para un servicio (apache2)

systemctl stop apache2
systemctl start apache2
systemctl restart apache2
systemctl reload apache2
systemctl reload-or-restart apache2
systemctl status apache2
systemctl is-active apache2
systemctl is-enabled apache2
systemctl is-failed apache2
systemctl cat apache2.service
systemctl list-dependencies apache2.service
systemctl enable apache2
systemctl disable apache2

editar servicios

systemctl edit apache2.service
systemctl edit --full apache2.service

estado del sistema

systemctl is-system-running
systemctl status
systemctl list-units --failed

opciones generales de systemd

systemctl list-units
systemctl list-units --failed
systemctl list-units --all
systemctl list-units --all --state=inactive
systemctl list-units --all --state=active
systemctl list-units --type=service

ver servicios configurados al arrancar

systemctl list-unit-files

opciones generales del sistema

systemctl halt
systemctl poweroff
systemctl reboot

ver dns del sistema

systemd-resolve --status

resetear conexiones de audio/mic (para auriculares)

systemctl --user restart pulseaudio.service

logs

journalctl
journalctl -b          # desde el ultimo boot
journalctl -k          # kernel - dmesg
journalctl -p err -b   # errores desde el ultimo boot
journalctl -n 20       # ultimas 20 lineas
journalctl -x          # agrega textos explicativos
journalctl -e          # al final del less
journalctl --since yesterday
journalctl --since "2015-01-10" --until "2015-01-11 03:00"
journalctl -u apache2.service
journalctl -u apache2.service -u mysql.service
journalctl _UID=33
journalctl --no-pager  # tira a consola sin el less

'mask' is a state of unit files which is considered as the “third level of off” (stop-1st, disable-2nd, mask-3rd). The services labeled as masked can neither be started manually (using the start command) nor by systems (at system boot). Therefore, use caution when employing the systemctl mask command on a service.