It would have been much easier if you'd created the directory names as 'YYYYMMDD' then they would have sorted naturally with little effort.

BTW, opendir/readdir are too low level and always a pain to use unless you really have to. You could try File::Find::Rule instead

use v5.20;
use warnings;

use File::Find::Rule;

my @dirs = File::Find::Rule->directory()->maxdepth(1)->in('.');

say $_ for @dirs;
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