my @sorted = sort { -s $a <=> -s $b } @files;

##</code><code>##

use strict;
use warnings;
{
    opendir (my $dir, '.') or die "Can't open the directory.\n$!";
    local $, = "\n";
    print sort { -s $a <=> -s $b } grep -f, readdir($dir);
    closedir $dir;
}