code: function fail(context, err) {
      var message;
      switch (err.code) {
          case "ENOENT":
              message = err.path + ": No such file or directory";
              break;
          case "ENOSYS":
              message = "Command not supported";
              break;
          default:
              message = err["description"] || err.message;
              break;
      }
      
      return context.fail(message);
  }
docs: fail command with an error message