lib/config.js
function parseCommandLineArgument(arg, fn) {
  if (typeof(fn) !== 'function')
    return;

  if (Array.isArray(arg)) {
    arg.forEach(function(item) {
      fn.call(null, item);
    });
  } else {
    if (arg !== null && arg !== undefined) {
      fn.call(null, arg);
    }
  }
}
function parseCommandLineArgument(arg, fn) {
  if (typeof(fn) !== 'function')
    return;

  if (Array.isArray(arg)) {
    arg.forEach(function(item) {
      fn.call(null, item);
    });
  } else {
    if (arg !== null && arg !== undefined) {
      fn.call(null, arg);
    }
  }
}
argv.X will be an array if multiple -X options are provided otherwise argv.X will just be a scalar value