perl -le '$,=", ";print sort { $#$b <=> $#$a or $a cmp $b}'\
        -e 'keys %{{ map {@$_ = (@$_, $_); $_=>1} @ARGV}};'\
 0 _ __ 0 __ __  0 0 00 @ % $ % ^ ^_


result-> 0, __, %, $, 00, @, ^, ^_, _