code: function sysctl(options, cb) {
    if (typeof arguments[0] != 'object'
      && typeof arguments[1] != 'function') {
  
      throw new Error('Invalid arguments. Signature: (object, callback)');
    }
  
    /*
     * Build cmd to execute.
     */
    var cmd = ['sysctl'];
    var args = [];
  
    switch (options.action) {
      case 'enable':
        args = args.concat('-w', options.path + '=1'); // It can not be --write since is not supported in older kernels.
  
        break;
      case 'disable':
        args = args.concat('-w', options.path + '=0'); // It can not be --write since is not supported in older kernels.
  
        break;
      case 'status':
        args = args.concat('--values', options.path);
  
        break;
      default:
        break;
    }
  
    /*
     * Execute command.
     */
    exec(cmd.concat(args).join(' '), function (error, stdout, stderror) {
      if (error) {
        cb(stderror.replace(/\n/g, '') + '. Executed command line: ' + cmd.concat(args).join(' '));
      }
      else {
        var result = null;
        if (options.action == 'status') {
          result = stdout;
        }
  
        cb(null, result);
      }
    });
  }
docs: /*
  options.action
  options.path