#!/usr/bin/perl

use strict;
use warnings;
use XML::Twig;

XML::Twig->new( twig_handlers => { H1 => sub { $_->set_tag( 'section1'); },
                                   H2 => sub { $_->set_tag( 'section2'); },
                                 },
                pretty_print => 'indented',
              )
         ->parsefile( $ARGV[0])
         ->print;