use strict;
use warnings;
use File::Find::Rule;
my $dir = ".";
my @files = File::Find::Rule->file()->in($dir);
print "$_\n" for sort { lc $a cmp lc $b } @files;
####
.project
10B.xml
10b.xml
1354903584-3827.xlsx
5a.xml
67.xml
6adh.pdb
arrays.pl
atom.pdb
Bio_SeqIO.pl
...
##
##
use strict;
use warnings;
use File::Find::Rule;
use Sort::Naturally;
my $dir = ".";
my @files = File::Find::Rule->file()->in( $dir );
print "$_\n" for nsort @files;
##
##
5a.xml
6adh.pdb
10b.xml
10B.xml
67.xml
1354903584-3827.xlsx
arrays.pl
atom.pdb
Bio_SeqIO.pl
Book1.xls