@in = (
    ['the cat sat'],
    ['the ', 'cat', 'sat'],
    ['the cat', 'sat'],
    ['the', 'cat', 'sat'],
);

{
    local $" = '';
    @out =  sort { "@$b" cmp "@$a" } @in;
}

use Data::Dumper;
# munge the output for compactness and to make it look nicer
$Data::Dumper::Indent = 0;
print map {s/\[/\n        \[/g; $_} Dumper \@out;

__DATA__
$VAR1 = 
        [
        ['the','cat','sat'],
        ['the ','cat','sat'],
        ['the cat','sat'],
        ['the cat sat']];