---

Quick Summary: lsof -t -i :<port> | xargs kill -9

The Unix command lsof ("list open files") allows you to view which process is listening on a specific port. This is useful when you cannot track down the process that's using a port, such as a webserver listening on 8080.

The see which process(es) are running on a port:

sudo lsof -i :<port>

example: sudo lsof -i :8080

Explaination:

-i Displays processes listening on an Internet address

Automatically kill the process listening on a port:

Pipe the process ID into the kill command to kill it:

lsof -t -i :<port> | xargs kill -9

example: lsof -t -i :3000 | xargs kill -9

Explaination:
-t: Terse output. Only displays the process ID number
xargs: Takes the process ID from standard output and makes it the arguemnt to kill
kill -9: Sends the SIGKILL signal to the process, causing it to terminate immediately