Work With Systemd

List all running services
## systemctl

Activates a service immediately:
# systemctl start foo.service

Deactivates a service immediately:
# systemctl stop foo.service

Enables a service to be started on bootup:
# systemctl enable foo.service

Check whether a service is already enabled or not:
# systemctl is-enabled foo.service; echo $?

Check mount units
systemctl list-units --type=mount

Check running services
systemctl list-units --type=service

Check journal logs for service
journalctl -f -u postgresql