log.bash

# if i don't parseInt the app_port var i get this
> app_port=2131 node server
node.js:201
        throw e; // process.nextTick error, or 'error' event on first tick
              ^
TypeError: Object 2131 has no method 'on'
    at new Manager (/home/alejandromg/9539-92fd447a71e931bda296344ae90b9f48/node_modules/socket.io/lib/manager.js:101:10)
    at Object.listen (/home/alejandromg/9539-92fd447a71e931bda296344ae90b9f48/node_modules/socket.io/lib/socket.io.js:71:10)
    at Object.<anonymous> (/home/alejandromg/9539-92fd447a71e931bda296344ae90b9f48/server.js:4:31)
    at Module._compile (module.js:441:26)
    at Object..js (module.js:459:10)
    at Module.load (module.js:348:31)
    at Function._load (module.js:308:12)
    at Array.0 (module.js:479:10)
    at EventEmitter._tickCallback (node.js:192:40)

server.js

// this works
var PORT = parseInt(process.env['app_port'],10) || 3000;

var io = require("socket.io").listen( PORT, function(){

io.sockets.on("connection",arrancar);

function arrancar(msg){
        msg.on("nuevoMensaje",emitir);
        }

function emitir(data){
        io.sockets.emit("mensaje",data);
        }

})