Listing directories

[Covert2String]

Hi, I saw this video: <!-- m --><a class="postlink" href="http://www.youtube.com/watch?v=UwGjbPwrMXo">http://www.youtube.com/watch?v=UwGjbPwrMXo</a><!-- m --> to list all files in a directorie, however I need to list all sub directories, like this:

->Main dir
-->file1
-->Sub dir
--->file2

I need the app to list it this way:

file1
Sub dir/file2

How can I do this?