sub direc {
...
my $dir = "/my_dir";
opendir DIR, $dir;

   # Read in all directories in /my_dir first
   my @month_dir = grep /^\d{8}$/, readdir(DIR);
   
   my $current_dir = $month_dir[0] || '';
   # I need to open only the latest directory here to continue
   # where I am stuck
   my $latest_dir  = ...

   # Now read in all files in latest directory found 
   opendir LATESTDIR, "$dir/$latest_dir";

   # Read in all files, but ignore '.' and '..'
   my @files = grep !/^\.{1,2}$/, readdir(LATESTDIR);
   
  my @files;
  foreach my $file (@files) {

    # I only want txt
    next unless ($file =~ m/\.txt$/);
    push @files, "$file";
 
   }

   closedir(LATESTDIR);
   
 closedir(DIR);

 return \@files;

}