.load ./server4.js
> var app = require('http').createServer(handler);
ReferenceError: handler is not defined
    at repl:1:40
    at REPLServer.self.eval (repl.js:110:21)
    at repl.js:249:20
    at REPLServer.self.eval (repl.js:122:7)
    at Interface.<anonymous> (repl.js:239:12)
    at Interface.emit (events.js:95:17)
    at Interface._onLine (readline.js:202:10)
    at Interface._line (readline.js:531:8)
    at Interface._ttyWrite (readline.js:814:20)
    at Interface.write (readline.js:294:24)
> io = require('socket.io').listen(app);
{ nsps:
   { '/':
      { name: '/',
        server: [Circular],
        sockets: [],
        connected: {},
        fns: [],
        ids: 0,
        acks: {},
        adapter: [Object] } },
  _path: '/socket.io',
  _serveClient: true,
  _adapter: [Function: Adapter],
  _origins: '*:*',
  sockets:
   { name: '/',
     server: [Circular],
     sockets: [],
     connected: {},
     fns: [],
     ids: 0,
     acks: {},
     adapter: { nsp: [Circular], rooms: {}, sids: {}, encoder: {} } } }
> //fs = require('fs');
undefined
> app.listen(4000);
TypeError: Cannot call method 'listen' of undefined
    at repl:1:5
    at REPLServer.self.eval (repl.js:110:21)
    at repl.js:249:20
    at REPLServer.self.eval (repl.js:122:7)
    at Interface.<anonymous> (repl.js:239:12)
    at Interface.emit (events.js:95:17)
    at Interface._onLine (readline.js:202:10)
    at Interface._line (readline.js:531:8)
    at Interface._ttyWrite (readline.js:814:20)
    at Interface.write (readline.js:294:24)
> function handler(req, res){
... /*  fs.readFile(_dirname + '/public/index.html',function(err,data){
.....           res.writeHead(200);
.....           res.end(data);
.....   });*/
... }
undefined
> io.sockets.on('connection', function(socket){
...     socket.emit('news',{hello:'world'});
...     socket.on('my other event',function(data){
.....           console.log(data);
.....   });
... });
{ name: '/',
  server:
   { nsps: { '/': [Circular] },
     _path: '/socket.io',
     _serveClient: true,
     _adapter: [Function: Adapter],
     _origins: '*:*',
     sockets: [Circular] },
  sockets: [],
  connected: {},
  fns: [],
  ids: 0,
  acks: {},
  adapter: { nsp: [Circular], rooms: {}, sids: {}, encoder: {} },
  _events: { connection: [Function] } }