utf8::decode($string);

##</code><code>##

use 5.010001;
use LWP::UserAgent;

my $url     = 'http://publib.boulder.ibm.com/infocenter/brjrules/v7r0m3/basic/tocView.jsp?toc=/com.ibm.websphere.ilog.jrules.doc/toc.xml';
my $content = LWP::UserAgent->new->get($url)->content;
utf8::decode($content);

$content =~ s { ([\x00-\x08\x0B\x0C\x0E-\x1F\x80-\x{1FFFFF}]) }
              { sprintf('[U+%04X]', ord($1)) }gex;

print $content;