正確には man lsof を参照して下さい。 $ sudo lsof -i TCP:8984 COMMAND PID USER FD TYPE DEVICE SIZE/OFF NODE NAME java 4914 m 114u IPv6 20871 0t0 TCP *:8984 (LISTEN) $ sudo lsof -i TCP:8000 COMMAND PID USER FD TYPE DEVICE SIZE/OFF NODE NAME firefox 2534 m 88u IPv4 117673 0t0 TCP localhost:47075->localhost:8000 (ESTABLISHED) firefox 2534 m 91u IPv4 125698 0t0 TCP localhost:47712->localhost:8000 (ESTABLISHED) fire