# sub file_normalize: based on https://www.perlmonks.org/?node_id=362893
sub file_normalize {
 use File::Spec::Functions;
 my $dir_ref = ".";
 my $file = shift;
 $file = File::Spec->rel2abs($file);
 my( $volume, $directories, $basename ) = File::Spec->splitpath(File::Spec->canonpath($file));
 my @dirs_in = File::Spec->splitdir( $directories );
 my @dirs_out;
 for my $dir (@dirs_in) {
  if ($dir eq "..") {
   pop @dirs_out;
  } else {
   push(@dirs_out, $dir);
  }
 }
 return File::Spec->abs2rel(File::Spec->catpath($volume, File::Spec->catdir(@dirs_out), $basename), $dir_ref);
}