Util

1. Spelling corrected: Schwartzian transform
2. No need to use parens around \d{8}.
3. I like ST better, but GRT is faster for large lists:
    http://www.perlmonks.org/?node_id=145659
4. Need to warn or die to show bad data when regex fails.
5. Perl 6 automatically does ST for you:
    my @sorted = @files.sort({ / SWITCH _ \d**8 _ (\d**6) / or die; $0; });

Util

package DateRange;

# Usage: `use DateRange qw( getDateArray );`
use strict;
use warnings;
use base qw(Exporter);
our $VERSION   = 1.00;
our @EXPORT_OK = qw( &getDateArray );
 
sub getDateArray {