text: const fs = require("fs");
  
  /*
  
   // create a folder
   fs.mkdir("sonu",(err) => {
     console.log("folder created");
     console.log(err);
   })
  
   */
  
  // create a file in any fiolder
  fs.writeFile(
    "sonu/bio.txt",
    "This is CRUD operation in asynchronous file system in core module in nodeJS",
    (err) => {
      console.log("file is created and first message added.");
      console.log(err);
    }
  );
  
  // add some another messages in file without overriding
  fs.appendFile(
    "sonu/bio.txt",
    "\nappend some another messages in CRUD operation in asynchronous file system in core module in node js.",
    (err) => {
      console.log("data added.");
      console.log(err);
    }
  );
  
  // read file data without bufferring
  fs.readFile("sonu/bio.txt", "UTF-8", (err, data) => {
    console.log(data);
    console.log(err);
  });
  
  // rename file
  fs.rename("sonu/bio.txt", "sonu/mybio.txt", (err) => {
    console.log("file renamed...");
    console.log(err);
  });
  
  /*
  
  // delete file
  fs.unlink("sonu/mybio.txt", (err) => {
    console.log("file deleted...");
    console.log(err);
  });
  
  // delete folder
  fs.rmdir("sonu", (err) => {
    console.log("folder deleted...");
    console.log(err);
  });
  
  */
  