code: function optionString(options) {
      return Object.keys(options).map(function (key) {
          var value = options[key];
          if (value === null) {
              return '-' + key;
          } else if (typeof value === 'number') {
              value += '';
          } else if (typeof value === 'string') {
              value = '"' + value.replace(/"/g, '\\"') + '"';
          }
          return '-' + key + '=' + value.replace(/`/g, '');
      }).join(' ');
  }
docs: Convert an options object to a string.