nodejs read all files in dir and replace some part of string inside

nodejs_read_replace.js

const cfgFolder = './cfg/';
const fs = require('fs');
const outFile = './out.txt';

fs.readdir(cfgFolder, (err, files) => {
    files.forEach(file => {
        fs.readFile(cfgFolder+file, 'utf8', (err, data) => {
            if(err) throw err;
            let pass = data.match(/(blabla.+)/i);
            pass = pass[0].trim();

            let ip = data.match(/blabla(.+) /i);
            ip = ip[1].trim();
            ip = ip.replace('254', '253');
            fs.appendFile(outFile, `${ip} ${pass} \n`, (err)=>{
                console.log(err);
            })
        });
    });
})

//iproute default(.+) 
//(bgtyhn.+)