<?xml version="1.0" encoding="UTF-8"?>
<policy name="Cur_policy" version="3.2.1">
  <policyrules>
    <Rule Action="allow" Enabled="true" RuleID="F68E32">
      <source addr="10.4.5.3" srcport="any"/>
      <dest addr="199.5.4.3" destport="80"/>
    </Rule>
    <Rule Action="allow" Enabled="true" RuleID="78E21D">
      <source addr="10.4.0.0-10.4.255.255" srcport="any"/>
      <dest addr="any" destport="80"/>
    </Rule>
  </policyrules>
</policy>

##</code><code>##

&lt;?xml version="1.0" encoding="UTF-8"?&gt;
&lt;policy name="Cur_policy" version="3.2.1"&gt;
  &lt;Rule Action="allow" Enabled="true" RuleID="F68E32"&gt;
    &lt;source addr="10.4.5.3" srcport="any"/&gt;
    &lt;dest addr="199.5.4.3" destport="80"/&gt;
  &lt;/Rule&gt;
  &lt;Rule Action="allow" Enabled="true" RuleID="78E21D"&gt;
    &lt;source addr="10.4.0.0-10.4.255.255" srcport="any"/&gt;
    &lt;dest addr="any" destport="80"/&gt;
  &lt;/Rule&gt;
&lt;/policy&gt;

##</code><code>##

#!/usr/bin/perl

use warnings;
use strict;

use XML::Twig;

my ( $in_XML_file, $out_XML_file ) = @ARGV;

# create objects
my $ref_reader = XML::Twig-&gt;new( twig_handlers =&gt;
                                 {
                                    'policyrules' =&gt; \&policyrules_handler,
                                    'Rule' =&gt; \&rule_handler
                                    }
                                 );
$ref_reader-&gt;parsefile( $in_XML_file )
   or die "    $in_XML_file is not parsable\n";

open my $out_fh, '&gt;', $out_XML_file
    or die "    $out_XML_file cannot be written: $!";

$ref_reader-&gt;print( $out_fh );

close $out_fh;


sub policyrules_handler
{
   my( $t, $elt)= @_;      # arguments for all twig_handlers

#   $elt-&gt;delete;
}

sub rule_handler
{
   my( $t, $elt)= @_;      # arguments for all twig_handlers

   $elt-&gt;set_att( 'new_attr' =&gt; 'dummyValue' );
}