If you got multiple "_n" appendages in one run, this might have happened because File::Find was somehow following "links" (in unix, there are "symbolic links" and "hard links"; I think the comparable notion in MS-Windows is called "shortcuts") -- i.e. shortcuts/links may exist in your directory structure, such that there is more than one path to a single data file or directory, and File::Find would pursue all of them, and hit on some (sets of) files more than once.