Sometimes you receive a lot of files from a co-worker which does not make any sense to be separate like database scripts which will run on the same database schema and for which the order of the scripts running does not matter. For this it might be convenient for you to merge all these files into one file.
To do that using DOS you need to have all your files in one folder and then open the command line (Start>Run>cmd then enter) and then change directory to the folder which you have all your files and type the following command on the command prompt:
type * >> ../combined.txt
This will create a files called combined.txt in the parent folder of your files folder which contains all the contents of the files merged in the same order they are displayed using the dir command.