To compile this, you execute the mono C# compiler:

mcs dirtrav.cs

Which should give us a file named dirtrav.exe -- it's interesting to note that because this file is in IL, it can be run on Windows as well.

Now you can just run the exe:

csharp-dirtraverse# ./dirtrav.exe top
top/dirone (d)
  top/dirone/CVS (d)
    top/dirone/CVS/Entries (f)
    top/dirone/CVS/Repository (f)
    top/dirone/CVS/Root (f)
top/dirtwo (d)
  top/dirtwo/dirtwofileone (f)
  top/dirtwo/dirtwofilethree (f)
  top/dirtwo/dirtwofiletwo (f)
  top/dirtwo/CVS (d)
    top/dirtwo/CVS/Entries (f)
    top/dirtwo/CVS/Repository (f)
    top/dirtwo/CVS/Root (f)
top/fileone (f)
top/filethree (f)
top/filetwo (f)
top/CVS (d)
  top/CVS/Entries (f)
  top/CVS/Repository (f)
  top/CVS/Root (f)