foreach (@contentsOfDataBase){
  chomp ($_);
  print "$_";
  @inDirectoryNotInDataBase = grep {!"$_"} @contentsOfDirectory;
  print "@inDirectoryNotInDataBase", "\n";
}

foreach (@copyOfContentsOfDirectory){
  print "$_";
  @pdfNoMatchingDirectory = grep (!$_, @contentsOfDataBase);#for current element in @copyOfContentsOfDirectory find all elements of @contentsOfDataBase that are not a match
  print "@pdfNoMatchingDirectory", "\n";
  
}