Regex rgx = new Regex(@"http://www.XXXX.com/file/d{10}/");string path = @"H:", newTxt = @"H:
ewTxt.txt"; var query1 = from f in Directory.GetFiles(path) let arr = File.ReadAllLines(f) where f.EndsWith(".txt") select new { content = (from c in arr where rgx.IsMatch(c) select c) }; query1.ToList().ForEach(item => File.AppendAllLines(newTxt, item.content)); foreach (var str in File.ReadAllLines(newTxt)) { Console.WriteLine(str); }