text: //common fs.writefile(filename, data[, options], callback)
  //options : path for file string name including path, data for String or Buffer to be written to the file
  //options-{encoding, mode, flag} default encoding is utf-8
  //mode is in octal 0666
  //callback = callback function with 1 error parameter to return message when error is occured while writing
  
  var fs = require("fs");
  
  console.log("Going to write into existing file");
  fs.writeFile('input.txt', 'Simply Easy Learning!', function(err) {
      if(err) {
          return console.error(err);
      }
  
      console.log("Data written successfully!");
      console.log("Let's read newly written data");
  
      fs.readFile('input.txt', function (err, data) {
          if(err) {
              return console.error(err);
          }
          console.log("Asynchronous read: " + data.toString());
      });
  });
  