$$mhash{entries}{$msg}{text} =~ s!http://(.+?)(\s|$)!"\[<a href=\"http://$1\">Link</a>\]"!ge;

##</code><code>##

my $string = $$mhash{entries}{$msg}{text};
$string =~ s!http://(.+?)(\s|$)!"\[<a href=\"http://$1\">Link</a>\]"!ge;