my @files=grep {$_ ne '.' && $_ ne '..'}
   @files=readdir(DIR);
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Not directly related to your question, but I've seen this construct a couple of times now in code you posted, so I thought it's maybe worth commenting on... before it becomes a habit :)

The 'normal' way to write this would be

   my @files=grep {$_ ne '.' && $_ ne '..'} readdir(DIR);
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No need to assign the list of files to an intermediate array — which is also a different (i.e. package) variable from the first lexical my @files, BTW.

Has anyone ever suggested to try use strict?  ;)