void Main()
{
  using (var client = new FtpClient())
  {
    client.Host = "ftp.kernel.org";
    client.Credentials = new NetworkCredential("anonymous", "me@me.com");
  
    Console.WriteLine("lettura ftp");
    var list = client.GetNameListing("/pub/linux/kernel/v3.x/");
    
    Console.WriteLine("\ntutti\n");
    foreach (var element in list)
    {
      Console.WriteLine(element);
    }
    
    Console.WriteLine("\nsolo quelli da cancellare\n");
    foreach (var element in list.Where (t => t.EndsWith(".gz", StringComparison.InvariantCultureIgnoreCase)))
    {
      Console.WriteLine(element);
      client.DeleteFile(element);
    }
  }
}