code: function parsePorts(arg) {
    // coerce and split
    var ports = ('' + arg).split(':');
    if (ports.length !== 2) {
      panic('Error parsing ports.');
    }
  
    // parse ints
    var devicePort = Number((ports[0] === '') ? NaN : ports[0])
      , relayPort = Number((ports[1] === '') ? NaN : ports[1]);
  
    // NaN check em
    if (devicePort !== devicePort || relayPort !== relayPort) {
      panic('Error parsing ports.');
    }
  
    return [devicePort, relayPort];
  }
docs: Parse port arg string into array of ints (ie, '22:2222' -> [22, 2222])
  @param  {string} arg
  @return {integer[]}