using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Net;
using System.Net.Sockets;
using System.Text;

namespace ConsoleApplication2
{
    class Program
    {
        static void Main(string[] args)
        {
            var hostfile = "";
            var OSInfo = Environment.OSVersion;
            string pathpart = "hosts";
            if (OSInfo.Platform == PlatformID.Win32NT)
            {
                //is windows NT
                pathpart = @"system32\drivers\etc\hosts";
            }
            hostfile = Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.Windows), pathpart);

            if (!File.ReadAllLines(hostfile).Contains("123.123.123.123 download.talesrunner.com"))
            {
                File.AppendAllLines(hostfile, new String[] { "123.123.123.123 download.talesrunner.com" });
            }

            Console.ReadLine();
        }
    }
}