#!/usr/bin/perl

use strict;
use HTML::TokeParser::Simple;

my $htm = HTML::TokeParser::Simple->new( $ARGV[0] ) or die "oops: $!";

while ( my $token = $htm->get_token )
{
    if ( $token->is_tag() ) {
        print " " x length( $token->as_is );
    } else {
        print $token->as_is;
    }
}