console.log("welcome world of backend") const os = require('os') // console.log(os.cpus()) console.log(os.uptime()) to read a file by using readFile const { error } = require('console') const fs = require('fs') fs.readFile('./sample.txt','utf-8',(error, data)=>{ if(error){ console.log(error) } else{ console.log(data) } }) Using readFileSync method // comparing to both this exceute fast because O(n) let data = fs.readFileSync('./sample.txt','utf-8') console.log('sync',data) To write a new file => fs.writeFile('path','data','formate(utf-8)',(error)=>{ if (error) console.log(error) else console.log('File created success')}) fs.writeFile('./sampleForWriteFile.txt','Hai we created a new file','utf-8',(error)=>{ if(error) console.log(error) else console.log('File created Successfully') }) To write and read a sync method To write fs.writeFileSync('./sampleSync.txt','This is a sync method','utf-8') let syncdata = fs.readFileSync('./sampleSync.txt','utf-8') To create a server const http = require('http') const server = http.createServer((req,res)=>{ res.writeHead(200,{ "content-type":"text/html" }) res.end(`<h1>Hello Server Is runing</h1>`) }) server.listen(8000,()=>"server is running in 8000") TO create a json const http = require('http') const server = http.createServer((req,res)=>{ res.writeHead(200,{ "content-type":"application/json" }) res.end(JSON.stringify({ name:"anbu", email:"anbu@gmail.com" })) }) server.listen(8000,()=>console.log("server is lisning port 8000")) To write a file and read to listen the port const fs = require('fs') const http = require('http') let time = new Date().toLocaleString() const server = http.createServer((req,res)=>{ try { fs.writeFileSync('./date.txt',`${time}`,'utf-8') let data = fs.readFileSync('./date.txt','utf-8') res.writeHead(200,{ "content-type":"text/html" }) res.end(`${data}`) } catch (error) { console.log(error) } }) server.listen(8000,()=>console.log("server is lisning port 8000"))