How to restart Nginx in Ubuntu or other linux servers

I used this [sh file][1] to install Nginx. When I modify the `nginx.conf` and try to reload or restart Nginx it didn't restart. I used below command. sudo systemctl restart nginx gave me sudo: unable to resolve host localhost.localdomain sudo: systemctl: command not found and this one sudo service nginx restart sudo: unable to resolve host localhost.localdomain nginx: unrecognized service and this one sudo /etc/init.d/nginx restart sudo: unable to resolve host localhost.localdomain sudo: /etc/init.d/nginx: command not found [1]: https://github.com/dburianov/nginx/blob/master/deploy/deploy_nginx_rtmp_ubuntu.sh