cluster-example.js

#!/usr/bin/env node
(function () {
    'use strict';
    var request = require('request'),
        fs = require('fs'),
        cluster = require('cluster'),
        nCPUs = require('os').cpus().length;

    var imgs = [
        'http://upload.wikimedia.org/wikipedia/commons/a/af/Flag_of_South_Africa.svg',
        'http://upload.wikimedia.org/wikipedia/commons/9/9a/Flag_of_Afghanistan.svg',
        'http://upload.wikimedia.org/wikipedia/commons/thumb/3/36/Flag_of_Albania.svg/700px-Flag_of_Albania.svg.png',
        'http://upload.wikimedia.org/wikipedia/commons/thumb/b/ba/Flag_of_Germany.svg/800px-Flag_of_Germany.svg.png'
    ], label = 'Time to get all files';

    console.time( label );

    if ( cluster.isMaster ) {
        while ( nCPUs-- ) {
            cluster.fork();
        }
    } else {
        imgs.map(function ( img, i ) {
            var filename = img.split('/')[ img.split('/').length - 1 ], 
                file = request( img ).pipe( fs.createWriteStream( filename ) ); 

            if ( i === ( imgs.length - 1 ) ) {
                process.exit();    
            }
        });
    }

    console.timeEnd( label );
}).call( this );