my($dir)    = $ARGV[0] ||'';
my($maxage) = $ARGV[1] ||0; $maxage = int $maxage;

die "Can't operate without a target directory spec.  Op aborted.\n"
   unless length $dir; # dir could be named "0"
die qq[No such directory "$dir"\n] unless -e $dir;
die "Need max allowed age spec for files.  Op aborted.\n"
   unless $maxage; # zero values and non-numeric values not accepted.

sub gothere {
   my ($ddir) = @_;
   $ddir=~ s|$|/|;
   local *PDFDIR;
   opendir(PDFDIR, $ddir) or die $!;
   my(@files) = map {$ddir . $_} readdir(PDFDIR);
   closedir(PDFDIR) or warn $!;

   print qq[Nothing to do.  No files present in "dir".\n] and exit unless @files;

   foreach my $f (@files) {
      next if $f =~ /^\.+$/; #don't want . ..
      gothere($f) if -d $f;
      if ((int(-M $f) > $maxage) && (-f _) && $f=~/\.pdf$/i)
        {unlink $f or die qq[Can't unlink "$f"! $!];}
      print qq[Deleted "$f"\n];
   }
}
gothere($dir);
print "Done.\n\n" and exit;