A simple port scanner

portScanner.js

var net = require('net');
var parameters = process.argv.slice(2, process.argv.length);
var timeOut = 2000;
console.log(parameters)

if(parameters.length == 1 && parameters[0] == "help"){
	printHelp();
}

if(parameters.length != 2){
	printHelp();
}

main(parameters[0], parameters[1]);


function printHelp(){
	console.log("node scanner.js ip portRange");
	console.log("sample: node portScanner.js.js 192.168.1.33 80-2000");
	process.exit();
}

function main(ip, portRange){
	var ports = portRange.split('-');		
	if(ports.length != 2){
		printHelp();
	}	
	var pi = ports[0], pe = ports[1];
	while(pi <= pe){
		(function(ip ,port){
			var s = new net.Socket();
			//https://nodejs.org/dist/latest-v4.x/docs/api/net.html#net_socket_connect_options_connectlistener
			s.connect({
				port: port,
				host: ip
			}, function(){
				console.log("host", ip, "port", port, "alive")
				clearTimeout(to);
				s.destroy();
			})
			s.on('data', function(){
				s.destroy();
			})
			s.on('error', function(){
				s.destroy();
			})
			var to = setTimeout(function(){
				console.log("host");
				console.log("host", ip, "port", port, "dead");
				s.destroy();
			}, timeOut)
		})(ip, pi);
		pi++;
	}			
}