<?xml version="1.0" encoding="UTF-8"?>

<Servicelist xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="file:///files/service.xsd">

<Service Num="B7a" Name="temperature sensor">

<Des>It delivers actual temperature in the form ov Volts</Des>

<Customermodules>

   <Softwaremodule Service="ADC" Path="/main/ADCservice.xml"/>

</Customermodules>

<Suppliermodules>

   <Softwaremodule Service="input" Path="/main/inputservice.xml"/>
   <Softwaremodule Service="signal" Path="/main/signalservice.xml"/>
   <Hardwaremodule Type="engine"  Nr="18" Servicenum="1" Path="/main/engineservice.xml"/>
   <Hardwaremodule Type="motor"   Nr="7" Servicenum="1" Path="/main/motorservice.xml"/> 
   <Hardwaremodule Type="supply" Nr="1" Servicenum="1" Path="/main/supplyservice.xml"/>

</Suppliermodules>

</Service>

#!/usr/bin/perl
use warnings;
use strict;
use XML::LibXML;
use Carp;
use File::Find;
use File::Spec::Functions qw( canonpath );
use XML::LibXML::Reader;  
my %hash;
my @ARGV ="C:/Main";
die "Need directories\n" unless @ARGV;
find(
    sub {
        return unless ( /(_service\.xml)$/ and -f );
        extract_information();
        return;
    },
    @ARGV
);

sub extract_information {
    my ($path $hash) = $_;
	
if( my $reader = XML::LibXML::Reader->new( location => $path )){

        while ( $reader->nextElement( 'Service' )) {
         my $elem = $reader->getAttribute( 'Id');
         
		 $reader->nextElement( 'Customermodules' );         
		  my $elem1 = $reader->getAttribute( 'Service');
		 
		  $reader->nextElement( 'Suppliermodules' );         
		  my $elem2 = $reader->getAttribute('Service');
		  
		   $hash->{$elem} = $elem1;
		   push @{$hash{$elem}}, '$elem2';
}
						}
 return;
 }
  print my $num=keys%hash;