Using Ubuntu 18.
Calling this service “shutdown”
sudo nano /etc/systemd/system/shutdown.service
Contents. Include the full path to your down.sh shell script. In this example, it’s /opt/settings/scripts/down.sh, and it calls a service using curl which then speaks to a speaker that the server is shutting down.
[Unit] Description=My shutdown [Service] Type=oneshot RemainAfterExit=true ExecStop=/opt/settings/scripts/down.sh [Install] WantedBy=multi-user.target
Enable the service:
sudo systemctl daemon-reload sudo systemctl enable shutdown --now
Test it:
sudo shutdown -r now