On OSX you can display applications listening on a given port using the lsof the commands described below will show listening applications as well as the PID for each application
lsof -nP -i4TCP | grep LISTEN
lsof -nP -i4TCP:[PORT] | grep LISTEN
Where [PORT] is the given port you want to check for
lsof -nP -i4TCP:80 | grep LISTEN
Your output should look something similar to this :
idea 28856 ufasoli 15u IPv4 0xdc1e11a68e7f918b 0t0 TCP 127.0.0.1:17434 (LISTEN) idea 28856 ufasoli 52u IPv4 0xdc1e11a690bab54b 0t0 TCP 127.0.0.1:6942 (LISTEN) idea 28856 ufasoli 748u IPv4 0xdc1e11a690b9dccb 0t0 TCP 127.0.0.1:63344 (LISTEN) idea 28856 ufasoli 1076u IPv4 0xdc1e11a68e7fa54b 0t0 TCP 127.0.0.1:54243 (LISTEN) idea 28856 ufasoli 1082u IPv4 0xdc1e11a67124254b 0t0 TCP 127.0.0.1:54266 (LISTEN) rapportd 28871 ufasoli 5u IPv4 0xdc1e11a665f15b6b 0t0 TCP *:51387 (LISTEN) node 33709 ufasoli 28u IPv4 0xdc1e11a66304354b 0t0 TCP 127.0.0.1:4200 (LISTEN) java 34245 ufasoli 168u IPv6 0xdc1e11a66dd5f11b 0t0 TCP *:52439 (LISTEN) java 34245 ufasoli 182u IPv6 0xdc1e11a6803af4db 0t0 TCP *:33389 (LISTEN) java 34245 ufasoli 183u IPv6 0xdc1e11a6803afafb 0t0 TCP *:8080 (LISTEN)
