how to check if something is running on a port in Mac code example

Example 1: list used ports on mac

sudo lsof -PiTCP -sTCP:LISTEN

COMMAND     PID      USER   FD   TYPE             DEVICE SIZE/OFF NODE NAME
GitHub      850 grgarside   6u   IPv4 0x23c345381d089301      0t0  TCP localhost:25035 (LISTEN)

Example 2: running ports in mac

sudo lsof -PiTCP -sTCP:LISTEN