#!/usr/bin/env perl

use strict;
use warnings;

my @files = @ARGV || glob "*.xml"
    or die "No files specified!";

my %xmlstring = (
    Hzbprtype => qr/<kBPrType[^>]*>\s*52\s*<\/kBPrType>/,
    );
    
for my $file ( @files ) {
    my @cont = do { local(*ARGV, $_, $/); @ARGV = $file; $/ = "</BaseProduct>"; <>; }
        if ( -r $file );

    for ( @cont ) {

        if ( /$xmlstring{'Hzbprtype'}/gs ) {
            print "\nThis is impossible!";
        }

        
        if ( /$xmlstring{'Hzbprtype'}/gs ) {
            print "\nSo weit so gut...";
        }
    }
}