Learning to use ranges instead of arrays

[Bob Tolbert via Digitalmars-d-learn]

I find myself writing this code too much and i'm curious what D
idiom I am missing.
given a list of files (or any strings) and then maybe I want to
sort them and maybe I don't.

     string [] fileList;

     ... fill list

     if (sort) {
         string [] tempList;
         foreach(filename; sort(fileList)) {
             tempList ~= filename;
         }
         fileList = tempList;
     }

     foreach(filename, fileList) {
         ... do something;
     }

but I know this is ugly code, so I'm curious as to how to make it 
better. I suspect it is something very simple, about switching 
everything I do to 'ranges', but I can't see it yet.

Thanks for any input,
Bob