willsmannar replied to tomasz86's topic in Programming (C++, Delphi, VB/VBS, CMD/batch, etc.)In C# you can do it programmatically . Read those file one by one and store it ino a string and finally write the string to a single file. string line = null; System.IO.TextReader readFile = new StreamReader("filename.txt"); line = line + readFile.ReadToEnd(); read three files and write file write file System.IO.TextWriter writeFile = new StreamWriter("filename.txt"); writeFile.WriteLine("line"); check this link. http://csharp.net-informations.com/file/csharp-textwriter.htm wills.