gistfile1.js

var fs = require("fs");

var logPath = "C:\\wamp\\www\\sandbox\\node\\gigya\\log";
var dates = {};

fs.readdir(logPath, function(err, files) {
	files.forEach(function(i) {
		var m = i.match(/([0-9]+)/gi);
		if (typeof dates[m[0]] == "undefined") dates[m[0]] = [];
		
		dates[m[0]].push(i);
	});
	
	var content = "";
	for (a in dates) {
		content = "";
		dates[a].forEach(function(i) {
			content += fs.readFileSync(logPath+"\\"+i, "utf8");
		});
		fs.writeFile(logPath+"\\social_"+a+".log", content, "utf8", function(err) {
			if (err) throw err;
			console.log("WROTE: "+logPath+"\\social_"+a+".log");
		});
	}
});