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sub md5files {
   use File::Basename;
   
   my $dir      = $_[0];           # where the files are (must be a direct path from root /)
   my $what     = $_[1] || '*';    # what files, default = '*' (all files)
   my $md5file  = "$dir/checksums.md5";
   my %hash_md5;
   
   my @t = split(/ /, $what);
   
   open (MD5OUT, '>', $md5file ) or die "Err: $!";
    
   foreach my $f (@t) {
      foreach my $file2md5 (<$dir/$f>) {
         next if "$file2md5" eq "$md5file";
         my $md5 = &md5calc($file2md5);
         if($md5 ne "") {
            $file2md5 =~ s/$dir\///;
            print MD5OUT $md5 . "  " . $file2md5 . "\n";
            $hash_md5{$md5} = $file2md5;  
         } else {
            return "";
         }
      }
   }
   close MD5OUT;
   return %hash_md5;
} 
--------------8<--------------