How do I change port on node project?

Question

I'm trying to start my node project on my server but I keep getting a error message-

 Ready on port 4000

 events.js:69
       throw arguments[1]; // Unhandled 'error' event
                   ^
 Error: listen EADDRINUSE
      at errnoException (net.js:850:11)
      at Server._listen2 (net.js:995:14)
      at listen (net.js:1022:10)
      at Server.listen (net.js:1071:5)

I've set to port in my app.js file by-

 var server = app.listen(4000, function() {
     console.log('Ready on port %d', server.address().port);
 });

when I start in locally it works on port 4000 but it also runs on port 3000.

Does anyone have any suggestions, or able to help my solve this?

Answer 1

    app.set('port', process.env.PORT || 4000);

var server = app.listen(app.get('port'), function () {
util.log('Ready on port ' + server.address().port);
});

This makes port 4000 ready if available otherwise gives any free port by Node server

OR

you can check if the port is free by

netstat -anp | find 4000

for unix use

sudo netstat -tapen | grep ":4000 "