my %hash;
opendir( D, "." );
while ( $_ = readdir D ) {
    next unless (-f);
    push @{$hash{-s _}}, $_; # uses previous stat data (from -f)
}

for my $size ( sort {$a<=>$b} keys %hash ) {
    for  my $file ( sort @{$hash{$size}} ) {
        print "$size\t$file\n";
    }
}