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
});
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);
}