server.js

var cp = require('child_process');
var path = require('path');
var http = require('http'); 

var n = cp.fork(path.join(__dirname, 'test.js'));
var port = process.env.PORT || 3000;
 
http.createServer().listen(port);

n.send('hello');
n.on('message', function(m) {
    console.log(m);
});

test.js

process.on('message', function(m) {
    process.send(m + ', world!');
});