Controlling Services

Start / stop / restart

sudo systemctl start nginx
sudo systemctl stop nginx
sudo systemctl restart nginx      # Stop then start
sudo systemctl reload nginx       # Reload config without dropping connections

Enable / disable at boot

sudo systemctl enable nginx       # Start automatically on boot
sudo systemctl disable nginx      # Don't start on boot (doesn't stop it now)
sudo systemctl enable --now nginx # Enable AND start immediately

Mask a service (hard-disable)

sudo systemctl mask nginx         # Prevents it from being started at all, even manually
sudo systemctl unmask nginx       # Allows it again

Reload systemd itself after editing a unit file

sudo systemctl daemon-reload

Required any time you edit a .service file directly, so systemd picks up the changes.

Quick reference