$ sudo dpkg -i Nessus-8.12.0-ubuntu910_amd64.deb
$ sudo systemctl start nessusd
$ sudo systemctl enable nessusd.service
$ sudo systemctl status nessusd.service
After these steps this message will appear:
● nessusd.service - The Nessus Vulnerability Scanner
Loaded: loaded (/lib/systemd/system/nessusd.service; enabled; vendor preset: enabled)
Active: active (running) since Tue 2020-10-20 16:06:00 -03; 23s ago
Main PID: 22062 (nessus-service)
Tasks: 12 (limit: 4432)
CGroup: /system.slice/nessusd.service
├─22062 /opt/nessus/sbin/nessus-service -q
└─22063 nessusd -q