my_first_io.js

/**
 * Write a program that uses a single synchronous filesystem operation to
 read a file and print the number of lines it contains to the console
 (stdout).

 The full path to the file to read will be provided as the first
 command-line argument.

 ----------------------------------------------------------------------
 HINTS:

 To perform a filesystem operation you are going to need the `fs`
 module from the Node core library. To load this kind of module, or any
 other "global" module, use the following incantation:

 var fs = require('fs')

 Now you have the full `fs` module available in a variable named `fs`.

 All synchronous (or blocking) filesystem methods in the `fs` module
 end with 'Sync'. To read a file, you'll need to use
 `fs.readFileSync('/path/to/file')`. This method will return a
 `Buffer` object containing the complete contents of the file.

 Documentation on the `fs` module can be found by pointing your browser
 here:
 /home/anca/lib/node_modules/learnyounode/node_apidoc/fs.html

 `Buffer` objects are Node's way of efficiently representing arbitrary
 arrays of data, whether it be ascii, binary or some other format.
 `Buffer` objects can be converted to strings by simply calling the
 `toString()` method on them. e.g. `var str = buf.toString()`.

 Documentation on `Buffer`s can be found by pointing your browser here:
 /home/anca/lib/node_modules/learnyounode/node_apidoc/buffer.html

 If you're looking for an easy way to count the number of lines in a
 string, recall that a JavaScript `String` can be `.split()` into an
 array of substrings. Perhaps split the string on `\n` and go from
 there.

 ----------------------------------------------------------------------
 */

var fs= require('fs');

if(process.argv.length==3){
	var filename=process.argv[2];
	var content = fs.readFileSync(filename).toString();
	console.log(content.split("\n").length);
}