use strict;
use warnings;
use diagnostics;
open(my $text, '<', "C:/Users/Customer/Desktop/New folder/Perl/1dfre10.TXT");
open(my $out,  '>', "C:/Users/Customer/Desktop/New folder/Perl/1dfre10.OUT");
undef($/);
my $all_text = <TEXT>;
$all_text = lc($all_text);
$all_text =~ s/[^a-z\-\']/ /g;
my @wordarray = split(/[\n\s]+/, $all_text);
...