code: function up(options, callback) {
    return this.exec('ifconfig ' + options.interface +
      ' ' + options.ipv4_address +
      ' netmask ' + options.ipv4_subnet_mask +
      ' broadcast ' + options.ipv4_broadcast +
      ' up', callback);
  }
docs: The **ifconfig up** command is used to bring up an interface with the
  specified configuration.
  
  @static
  @category ifconfig
  @param {object} options The interface configuration.
  @param {function} callback The callback function.
  @returns {process} The child process.
  @example
  
  var options = {
  interface: 'wlan0',
  ipv4_address: '192.168.10.1',
  ipv4_broadcast: '192.168.10.255',
  ipv4_subnet_mask: '255.255.255.0'
  };
  
  ifconfig.up(options, function(err) {
  // the interface is up
  });