Here's my passing scripts for running learnyounode https://github.com/rvagg/learnyounode#learn-you-the-nodejs-for-much-win.

babySteps.js

var args = process.argv.slice(2);
var total = 0;

for (var i = 0, len = args.length; i < len; i++) {
    total += Number(args[i]);
}

console.log(total);

filteredLs.js

var fs = require('fs');
var path = require('path');
var args = process.argv.slice(2);
var dirpath = args[0];
var ext = args[1];

fs.readdir(dirpath, function (err, list) {
    list.filter(function (name) {
        var regex = new RegExp(ext);
        if (regex.test(path.extname(name))) {
            console.log(name);
        }
    });
});

filterFiles.js

var fs = require('fs');
var path = require('path');

module.exports = function (dirpath, ext, cb) {
    fs.readdir(dirpath, function (err, list) {
        var files = [];

        if (err) {
            return cb(err);
        }

        list.filter(function (name) {
            var regex = new RegExp(ext);
            if (regex.test(path.extname(name))) {
                files.push(name);
            }
        });

        cb(null, files);
    });
};

firstAsyncIo.js

var fs = require('fs');
var args = process.argv.slice(2);
var path = args[0];

fs.readFile(path, function (err, data) {
    var newlines = data.toString();

    newlines = newlines.split('\n');

    console.log(newlines.length - 1);
});

firstIo.js

var fs = require('fs');
var args = process.argv.slice(2);
var path = args[0];
var fileContents = fs.readFileSync(path);
var newlines = fileContents.toString();

newlines = newlines.split('\n');

console.log(newlines.length - 1);

helloWorld.js

console.log('HELLO WORLD');

httpClient.js

var http = require('http');
var url = process.argv[2];

http.get(url, function (res) {
    res.setEncoding('utf8');
    res.on('data', console.log);
});

httpCollect.js

var http = require('http');
var bl = require('bl');
var url = process.argv[2];

http.get(url, function (res) {
    res.pipe(bl(function (err, data) {
        data = data.toString();
        console.log(data.length);
        console.log(data);
    }));
});

httpFileServer.js

var http = require('http');
var fs = require('fs');

http.createServer(function (req, res) {
    fs.createReadStream(process.argv[3]).pipe(res);
}).listen(process.argv[2]);

httpJsonApiServer.js

var http = require('http');
var url = require('url');

http.createServer(function (req, res) {
    var output;
    var obj = url.parse(req.url, true);
    var date = new Date(obj.query.iso);

    function unixtime(time) {
        return { "unixtime": time.getTime() };
    }

    function parsetime(time) {
        return { "hour": time.getHours(), "minute": time.getMinutes(), "second": time.getSeconds() };
    }
    
    if (obj.pathname === '/api/unixtime') {
        output = unixtime(date);
    }
    if (obj.pathname === '/api/parsetime') {
        output = parsetime(date);
    }

    if (output) {
        res.writeHead(200, { 'Content-Type': 'application/json'});
        res.end(JSON.stringify(output));
    } else {
        res.writeHead(404);
        res.end();
    }
}).listen(process.argv[2]);

httpUppercaserer.js

var http = require('http');
var map = require('through2-map');

http.createServer(function (req, res) {
    if (req.method !== 'POST') {
        return res.end('Invalid request format.\n');
    }
    req.pipe(map(function (chunk) { return chunk.toString().toUpperCase(); }))
        .pipe(res);
}).listen(process.argv[2]);

jugglingAsync.js

var http = require('http');
var bl = require('bl');
var args = process.argv.slice(2);
var arr = ['', '', ''];

function responseReady(arr) {
    if (arr.every(function (item) { return item !== ''; }) ) {
        arr.forEach(function (item) {
            console.log(item);
        });
    }
}

function httpGet(i) {
    http.get(args[i], function (res) {
        res.pipe(bl(function (err, data) {
            data = data.toString();
            arr[i] = data;
            responseReady(arr);
        }));
    });
}

for (var i=0; i < 3; i++) {
    httpGet(i);
}

modular.js

var filterFiles = require('./filterFiles');
var args = process.argv.slice(2);
var dirpath = args[0];
var ext = args[1];

filterFiles(dirpath, ext, function (err, data) {
    data.forEach(function (name) {
        console.log(name);
    });
});

timeServer.js

var net = require('net');

function pad(num) {
    return (num < 10 ? '0' : '') + num;
}

net.createServer(function (socket) {
    var date = new Date();
    var time = date.getFullYear() + '-' +
        pad(date.getMonth() + 1) + '-' +
        pad(date.getDate()) + ' ' +
        pad(date.getHours()) + ':' +
        pad(date.getMinutes());
    socket.end(time + '\n');
}).listen(process.argv[2]);