code: function enable(options, callback) {
    var file = options.interface + '-wpa_supplicant.conf';
  
    var command = 'wpa_passphrase "' + options.ssid + '" "' + options.passphrase
      + '" > ' + file + ' && wpa_supplicant -i ' + options.interface + ' -B -D '
      + options.driver + ' -c ' + file + ' && rm -f ' + file;
  
    return this.exec(command, callback);
  }
docs: The **wpa_supplicant enable** command is used to join a wireless network
  on a specific network interface.
  
  @static
  @category wpa_supplicant
  @param {object} options The wireless network configuration.
  @param {function} callback The callback function.
  @returns {process} The child process.
  @example
  
  var wpa_supplicant = require('wireless-tools/wpa_supplicant');
  
  var options = {
  interface: 'wlan0',
  ssid: 'RaspberryPi',
  passphrase: 'raspberry',
  driver: 'wext'
  };
  
  wpa_supplicant.enable(options, function(err) {
  // connected to the wireless network
  });