Unix/Linux/Mac OS: release/free TCP/IP port

• check which process is listening to (using) the port:

  fuser 8080/tcp

  It will returns the pid of the process, like below:

  8081/tcp:             7391

  , you can then use the process id to find which application is using the port:

  ps aux | grep 7391

• to kill the process that is using the port, you can simply do:

  sudo fuser -k 8080/tcp