Apply Regex to all files in directory, using node js

applyRegexToAllFilesInDirectory

var fs = require('fs');

function readFiles(dirname, onFileContent, onError) {
  fs.readdir(dirname, function(err, filenames) {
    if (err) {
      onError(err);
      return;
    }
    filenames.forEach(function(filename) {
      fs.readFile(dirname + filename, 'utf-8', function(err, content) {
        if (err) {
          onError(err);
          return;
        }
        onFileContent(filename, content);
      });
    });
  });
}


readFiles('./', function(filename, content) {
console.log(filename);
  // var newcontent=content.replace(/\n"\nauthor/,"\nauthor");
var newcontent=content.replace(/title:\s*"([^"]*)\nauthor/,"title: \"$1\"\nauthor");
  fs.writeFile(filename,newcontent,{encoding:'utf8'},
    function(){
    console.log('OK '+filename);
    });
}, function(err) {
  throw err;
});