use 5.010;
use strict;
use warnings;
use Carp;

my $var = 'QeTEv2804';
printf "%s.\n", $var;

open my $debug, '>>', 'debug.txt' or confess "Couldn't open file: $!";
printf $debug "%s.\n", $var;
close $debug;
##</code><code>##

$> hexdump -C debug.txt
00000000  51 65 54 45 76 32 38 30  34 2e 0a                 |QeTEv2804..|
0000000b