Service Won't Start

systemctl status service-name

# Last 50 logs
journalctl -u service-name -n 50

# Real-time logs (useful to see what happens on restart)
journalctl -u service-name -f

# Logs from last system boot
journalctl -u service-name -b

# Start
systemctl start service-name

# Stop
systemctl stop service-name

# Restart
systemctl restart service-name

# Reload configuration without downtime
systemctl reload service-name

# Enable on automatic startup
systemctl enable service-name

# Disable automatic startup
systemctl disable service-name

# Test configuration
nginx -t

# See the specific error
journalctl -u nginx -n 20

apache2ctl configtest
journalctl -u apache2 -n 20

journalctl -u mariadb -n 30
# or
cat /var/log/mysql/error.log | tail -30

mysqlcheck --all-databases --auto-repair -u root -p

journalctl -u php8.2-fpm -n 20
php-fpm8.2 --test

# Who uses port 80?
ss -tlnp | grep :80

# or
lsof -i :80

# Kill the process using the port
kill -9 PID

# Reset failure counter
systemctl reset-failed service-name

# Then restart
systemctl start service-name

# List all services in error
systemctl --failed

# Check file owner (example for nginx)
ls -la /var/www/example.com/
ls -la /etc/nginx/

# Fix permissions
chown -R www-data:www-data /var/www/example.com/
chmod -R 755 /var/www/example.com/