sudo systemctl start nginx
sudo systemctl stop nginx
sudo systemctl restart nginx
sudo systemctl reload nginx      # Reload config without restart
systemctl status nginx           # Check status (no sudo needed)
Is it running?
systemctl is-active nginx        # “active” or “inactive”
systemctl is-failed nginx        # “failed” or “active”

# Start on boot
sudo systemctl enable nginx
Start on boot AND start now
sudo systemctl enable —now nginx
Don’t start on boot
sudo systemctl disable nginx
Check if enabled
systemctl is-enabled nginx       # “enabled” or “disabled”

# All running services
systemctl list-units --type=service --state=running
All services (including stopped)
systemctl list-units —type=service —all
Failed services
systemctl —failed
All enabled services
systemctl list-unit-files —type=service —state=enabled

# Logs for a service
journalctl -u nginx
Follow (stream) logs
journalctl -u nginx -f
Last 50 lines
journalctl -u nginx -n 50
Since a time
journalctl -u nginx —since “1 hour ago”
journalctl -u nginx —since “2026-03-14 10:00”
Only errors
journalctl -u nginx -p err
Boot logs
journalctl -b                    # Current boot
journalctl -b -1                 # Previous boot
Disk usage
journalctl —disk-usage
Clean old logs
sudo journalctl —vacuum-time=7d   # Keep last 7 days
sudo journalctl —vacuum-size=500M # Keep max 500MB

# /etc/systemd/system/myapp.service
[Unit]
Description=My Node.js App
After=network.target
[Service]
Type=simple
User=deploy
WorkingDirectory=/home/deploy/myapp
ExecStart=/usr/bin/node dist/index.js
Restart=on-failure
RestartSec=5
Environment=NODE_ENV=production
Environment=PORT=3000
[Install]
WantedBy=multi-user.target

# After creating/editing the file:
sudo systemctl daemon-reload     # Reload unit files
sudo systemctl enable --now myapp
systemctl status myapp