Here are two options for Sync or Async depending on what you want.
var fs = require('fs');
function readWriteAsync() {
fs.readFile('filelist.txt', 'utf-8', function(err, data){
if (err) throw err;
var newValue = data.replace(/^\./gim, 'myString');
fs.writeFile('filelistAsync.txt', newValue, 'utf-8', function (err) {
if (err) throw err;
console.log('filelistAsync complete');
});
});
}
function readWriteSync() {
var data = fs.readFileSync('filelist.txt', 'utf-8');
var newValue = data.replace(/^\./gim, 'myString');
fs.writeFileSync('filelistSync.txt', newValue, 'utf-8');
console.log('readFileSync complete');
}
readWriteAsync();
readWriteSync();