is-port-available.js

'use strict';

// pick a random port between 1025 and 65535
// check using netstat to see if port is used

var exec = require('child_process').exec;
var port;
var _port;
var interval;

var handle = function(err, stdout, stderr) {
    if (!stdout.trim().length) {
      console.log('port ' + _port + ' available!');
      port = _port;
      clearInterval(interval);
    }
};

interval = setInterval(function() {
  _port = Math.floor(Math.random() * 65535) + 1025;
  exec('netstat -na | grep ' + _port, handle);
}, 500);