I am having a bit of trouble understanding what you want. But if appears that you want a report based upon a subset of all .pdf files underneath some directory.

The code below will find all files ending in .pdf in any directory in $base_dir or any directory beneath $base_dir. @pdf_files will contain the full path name to each .pdf file. From this you can find out if each file in ALLFILES exists or not.

If you want a list of all directories that do not contain .pdf files, the code is a bit different. I'm not sure what you mean by eligible or ineligible. Could you show a more concise version of desired output?

#!/usr/bin/perl -w
use strict;
use File::Find;

my $base_dir = "C:/Temp";
my @pdf_files;

find(\&collect_pdf_files, $base_dir);
print @pdf_files;

sub collect_pdf_files
{
   return unless (-f);      # only real files, not directories
   return unless (/.pdf$/); # continue if name ends in .pdf
   push (@pdf_files, $File::Find::name);
}

#prints: C:/Temp/something.pdf
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