my-first-io.js

//Create a file named my-first-io.js.  
//Write a program that uses a single synchronous filesystem operation to read a file and print the number of newlines (\n) it contains to the console (stdout), similar to running cat file | wc -l. The full path to the file to read will be provided as the first command-line argument (i.e., process.argv[2]). You do not need to make your own test file.  

var fs = require('fs')
var file = process.argv[2]
var content = fs.readFileSync(file)
var str = content.toString()
var allLines = str.split('\n')
console.log(allLines.length -1)