Issue with Express.js! (Node.js)

When I run Express.js with command "node app", it's runs and then ends!

My platforms are a Ubuntu and Windows 7 installation. I have this problem in both of them!

I copy these from CMD:

C:\> cd express

C:\express> node app

C:\express>

My App.js is like this:

var express = require('express'); var http = require('http'); var path
= require('path'); var favicon = require('static-favicon'); var logger = require('morgan'); var cookieParser = require('cookie-parser'); var bodyParser = require('body-parser');

var routes = require('./routes'); var users =
require('./routes/user');

var app = express();

// view engine setup app.set('views', path.join(__dirname, 'views'));
app.set('view engine', 'jade');

app.use(favicon()); app.use(logger('dev'));
app.use(bodyParser.json()); app.use(bodyParser.urlencoded());
app.use(cookieParser()); app.use(express.static(path.join(__dirname,
'public'))); app.use(app.router);

app.get('/', routes.index); app.get('/users', users.list);

/// catch 404 and forwarding to error handler app.use(function(req,
res, next) {
    var err = new Error('Not Found');
    err.status = 404;
    next(err); });

/// error handlers

// development error handler // will print stacktrace if
(app.get('env') === 'development') {
    app.use(function(err, req, res, next) {
        res.render('error', {
            message: err.message,
            error: err
        });
    }); }

// production error handler // no stacktraces leaked to user
app.use(function(err, req, res, next) {
    res.render('error', {
        message: err.message,
        error: {}
    }); });


module.exports = app;