check port using cli code example
Example 1: 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))
Example 2: check what ports are open linux
## if you use linux
sudo ss -tulw