How to restart Sonarr

[shawn8888]

Sonarr web UI crashes after a while. I tried to restart it by this:
sudo start nzbdrone
But it shows:
start: Unable to connect to Upstart: Failed to connect to socket /com/ubuntu/upstart: Connection refused
I also tried this:
mono /opt/NzbDrone/NzbDrone.exe
And I got this:
[Warn] SingleInstancePolicy: Another instance of Sonarr is already running.

So how do I stop it and restart?

[shawn8888]

OK, I found it!
Stop Sonarr:
systemctl stop sonarr.service
Start Sonarr:
systemctl start sonarr.service