gistfile1.txt

┌─[tadzik@yavin]─[/tmp] 
└─[%]─> ls chuj 
DUPA  script.pl
┌─[tadzik@yavin]─[/tmp] 
└─[%]─> /usr/bin/perl chuj/script.pl chuj
No need to move chuj/script.pl, it is already in lower case.
/tmp/chuj
Moving chuj/DUPA to chuj/dupa...
┌─[tadzik@yavin]─[/tmp] 
└─[%]─> ls chuj                          
DUPA  script.pl

use strict;
use warnings;
use File::Copy;
use File::Find;
use Cwd 'cwd';

find(&lowercase, @argv);

sub lowercase {
if ($_ eq '.') {
return 0;
};
my $original = $File::Find::name;
$_ =~ s/(^.*)/\L$1/g;
my $lowercased = $File::Find::dir . '/' . $_;
if ($original eq $lowercased) {
CORE::say 'No need to move ' . $original . ', it is already in lower case.';
return 0;
}
CORE::say cwd();
CORE::say 'Moving ' . $original . ' to ' . $lowercased . '...';
move("$original", "$lowercased");
}