docs: function list() {
    return installer.listPlugins(function(listErr, plugins) {
      if (listErr) {
        return out.error("error listing installed plugins: %s", listErr);
      }
      if (plugins.length === 0) {
        return out.success("no plugins found");
      }
      var string = "";
      for (var idx = 0; idx < plugins.length; idx++) {
        string += "  " + (idx + 1) + ".  " + plugins[idx].name +
          " - " + plugins[idx].description + "\n";
      }
      return out.success("installed plugins:\n%s", string);
    });
  }