chdir $dirName;

##</code><code>##

$txtfile = $dirName . '\\' . $txtfile;

##</code><code>##

use warnings;

##</code><code>##

#!/usr/bin/perl
use strict;
use warnings;

(my $prog_name = $0) =~ s| ^ (?: .* [\\/])? (.*) \.pl $ |$1|x;

(my $dirName = $ARGV[0])
    or die "Usage: $prog_name <directory>";

opendir(DIR, $dirName)
    or die "Unable to open directory '$dirName': $!";
my @files = grep(/ \.txt $ /x, readdir(DIR));
closedir(DIR);

chdir $dirName;     # <-- EITHER add this

foreach my $txtfile (@files)
{
  # $txtfile = $dirName . '\\' . $txtfile;     # <-- OR add this

    print "$txtfile\n";

    open(my $input_fh, '<', $txtfile)
        or die "Unable to open file '$txtfile' for reading: $!";

    undef($/);
    my $file = <$input_fh>;

    close $input_fh;

    $file =~ s/(<%--)?\s*<script(.*?)>/($1 ? '' : "\n<%-- ") . "<script$2>"/ige;
    $file =~ s=</script>\s*(-->)?='</script>' . ($1 ? '' : " -->\n")=ige;

    print $file;

    open(my $output_fh, '>', $txtfile)
        or die "Unable to open file '$txtfile' for writing: $!";
    print $output_fh $file;
    close $output_fh;
}