Programming

</Datainfo>
       <data>
        <test>22</test>
        <info>sensor value</info>
        <sensor>
            <sensor value="23" temp="25"/>
        </sensor>
    </data>
    <data>
        <test>23</test>
        <info>sensor value</info>
        <sensor>
            <sensor value="24" temp="27"/>
        </sensor>
    </data>
    <data>
        <test>22</test>
        <info>sensor value</info>
        <sensor>
            <sensor value="22" temp="26"/>
        </sensor>
    </data>
</Datainfo>

<Datainfo>
    <data>
        <test>22</test>
        <info>sensor value</info>
        <sensor>
            <sensor value="23" temp="25"/>
        </sensor>
    </data>
    <data>
        <test>23</test>
        <info>sensor value</info>
        <sensor>
            <sensor value="24" temp="27"/>
        </sensor>
    </data>
</Datainfo>

#!/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;
 use Digest::MD5 'md5';

 if ( @ARGV == 0 ) {
     push @ARGV, "c:/main/sav ";
     warn "Using default path $ARGV[0]\n  Usage: $0  path ...\n";
 }

 open( my $allxml, '>', "combined.xml" )
     or die "can't open output xml file for writing: $!\n";
 print $allxml '<?xml version="1.0" encoding="UTF-8"?>',
  "\n<Datainfo xmlns:xsi=\"http://www.w3.org/2001/XMLSchema-instance\">\n";
 #my %extract_md5;
 find(
      sub {
          return unless ( /(_str\.xml)$/ and -f );
          extract_information();
          return;
      },
      @ARGV
     );

 print $allxml "</Datainfo>\n";

 sub extract_information {
     my $path = $_;
     if ( my $reader = XML::LibXML::Reader->new( location => $path )) {
         while ( $reader->nextElement( 'Data' )) {
             my $elem = $reader->readOuterXml();
            print $allxml $elem;
             #my $md5 = md5( $elem );
             #print $allxml $reader->readOuterXml() unless ( #$extract_md5{$md5}++ );
         }

     }
     return;
 }