How to see what’s running on a port in Linux

user@hostname ~ $ sudo lsof -i -P -n | grep LISTEN | grep 1025

mailcatch  1104     root    9u  IPv4   27240      0t0  TCP *:1025 (LISTEN)

Reference:

https://www.cyberciti.biz/faq/unix-linux-check-if-port-is-in-use-command/

(first command)