How to Find the Process ID by Port on macOS

If it ever occurs to you that a process wouldn’t start under a desired port, it is possible to check which process is currently occupying that port.

In order to do a grep search, type the following command in your terminal and replace 8080 with the port you are investigating:

$ lsof -n -i :8080 | grep LISTEN

You will get a list of processes that are listening to port 8080 (in this case, it is process ID 19477). If no process is listening on that port, you won’t get any result.

nginx   19477 matthagemann    6u  IPv4 0xe9b6ad5cd425f509      0t0  TCP *:http-alt (LISTEN)

To kill process ID 19477, use $ kill 19477.