How many times have you looked up "That Port Is Already In Use"?

It's an easy fix: Find the PID of the process running on your PORT, kill that process

    [sudo] lsof -i :[PORT]
    kill -9 <PID>

LSOF And KILL In Detail

Understanding what exactly you just did to kill a process may help save you a Stack Overflow search for "That Port Is Already In Use"

lsof (list open files)

    [sudo] lsof -i :[PORT]

List the files of whose Internet address matches -i , but in this case we are just matching to a PORT number

kill

    kill -9 <PID>

kill the process with the specified PID, send a kill signal -9 To send a termination signal, use -15