You don't give enough detail and you haven't done any work at all that we can help you with. That's probably why you haven't gotten any replies yet.

Having said that, start by picking a language. Then read its docs to figure out how to walk a directory tree. Then write code that walks the tree and lists each file. Once you get that far, you shouldn't have too much trouble opening each file for reading so you can get to the next step.

Once you've done all that, you'll have some half-working steaming pile of code. At that point, you'll have more specific questions and we can provide more specific answers. None of the above should be difficult if you just look at a basic tutorial or two on your chosen language.

Have fun!

ShawnMilo