code: function (filename) {
      if (!fs.existsSync(filename)) {
          logger.error({
              method: "edit_add_cookbook_ids",
              filename: filename
          }, "file does not exist");
          return;
      }
  
      var encoding = 'utf8';
      var changed = false;
      var contents = fs.readFileSync(filename, encoding);
      var _replacer = function (full, cookbook_name) {
          changed = true;
          return util.format('homestar.cookbook(%s, "%s");', cookbook_name, uuid.v4());
      };
  
      contents = contents.replace(/^\s*homestar\s*.\s*cookbook\s*[(]\s*("[^"]*")\s*[)](\s*;)?/mg, _replacer);
      contents = contents.replace(/^\s*homestar\s*.\s*cookbook\s*[(]\s*('[^"]*')\s*[)](\s*;)?/mg, _replacer);
  
      if (changed) {
          fs.writeFileSync(filename, contents, {
              encoding: encoding
          });
          logger.info({
              method: "edit_add_cookbook_ids",
              filename: filename
          }, "updated recipe");
      }
  }
docs: This will edit a file and add UDIDs to Chapters
  
  <p>
  This is synchronous