code: function scan(options, callback) {
    var interface, show_hidden
    if (typeof options === 'string') {
      var interface = options;
      var show_hidden = false;
    } else {
      var interface = options.iface;
      var show_hidden = options.show_hidden || false;
    }
  
    this.exec('iw dev ' + interface + ' scan', parse_scan(show_hidden, callback));
  }
docs: The **iw scan** command is used to scan for wireless networks
  visible to a wireless interface. For convenience, the networks are
  sorted by signal strength.
  
  @static
  @category iw
  @param {string} interface The wireless network interface.
  @param {function} callback The callback function.