check with netstat services using which 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: linux query port use by pid

$ sudo ss -lptn 'sport = :80'
State   Local Address:Port  Peer Address:Port              
LISTEN  127.0.0.1:80        *:*                users:(("nginx",pid=125004,fd=12))
LISTEN  ::1:80              :::*               users:(("nginx",pid=125004,fd=11))