nodeIOFileRead.js

# Process I/O files synchronously in node.js

var fs = require('fs')

var contents = fs.readFileSync(process.argv[2])
var lines = contents.toString().split('\n').length - 1
console.log(lines)

// note you can avoid the .toString() by passing 'utf8' as the
// second argument to readFileSync, then you'll get a String!
//
// fs.readFileSync(process.argv[2], 'utf8').split('\n').length - 1

# Process I/O files asynchronously in node.js

var fs = require('fs')
var file = process.argv[2]

fs.readFile(file, function (err, contents) {
	// fs.readFile(file, 'utf8', callback) can also be used
	var lines = contents.toString().split('\n').length - 1
    console.log(lines)
     })