netstat command to check port code example
Example 1: linux query port use by pid
$ sudo netstat -nlp | grep :80
tcp 0 0 0.0.0.0:80 0.0.0.0:* LISTEN 125004/nginx
Example 2: netstat check port
sudo netstat -plnt
$ sudo netstat -nlp | grep :80
tcp 0 0 0.0.0.0:80 0.0.0.0:* LISTEN 125004/nginx
sudo netstat -plnt