code: function () {
  
          var backupFile;
  
          var source = this.source;
          var dirname = this.dirname;
          var basename = this.basename;
  
          // version < 0.2.1
          if (fs.existsSync(source + '.backup')) {
              backupFile = source + '.backup';
          } else {
              backupFile = path.join(dirname, '.font-spider', basename);
          }
  
          if (fs.existsSync(backupFile)) {
              utils.cp(backupFile, source);
          } else {
              utils.cp(source, backupFile);
          }
      }
docs: 字体恢复与备份