my %d;
foreach (@ARGV)
{
    my ($k, $v) = split (m/=/, $_, 2);
    $d{$k} = (defined $v ? $v : "");
}

#this is for checking only..
foreach (keys %d) { print "$_:" . $d{$_} . "\n"; }

##</code><code>##

my $defaults = {};
%defaults = map {(($_ =~ /([^\=]+)\=(.+)/)?($1 => $2):($_ => ''))} @ARGV;
print join(",", keys %defaults);