fork.js

var fork = require('child_process').fork;
var spawn = require('child_process').spawn;

for (var i = 0; i < 5; i++) {
  fork("watch.js");
  // var ls = spawn("node", ["watch.js"]);

  // ls.stdout.on('data', function(data) {
  //   process.stdout.write(data.toString());
  // });

  // ls.stderr.on('data', function(data) {
  //   console.log(data.toString());
  // });

  // ls.on('close', function(code) {
  //   console.log('child process exited with code ' + code);
  // });
}

watch.js

var myRequire = function(module) {
	var modulePath = require.resolve(module);
	if (require.cache[modulePath]) {
		delete require.cache[modulePath];
	}

	return require(module)
}

var fs = require('fs');

// watch files directory file
var p = __dirname + "/files/vvv.js";

fs.watch("files", function(event, filename) {
	var r = myRequire(p);
	console.log(process.pid);
	console.log(r);
});