use List::Util qw/ first /;

my %count;
$count{$_}++ for split /,/, $str1;
$count{$_}-- for split /,/, $str2;

my $different = defined first { $_ } values %count;

##</code><code>##

require Test::More;
my $equal = Test::More::eq_array(
    [ split ',', $str1 ],
    [ split ',', $str2 ],
);