or using Data::Dump::Streamer:

use strict;
use warnings;

use Data::Dump::Streamer;

$_ = "\x00" x 26;
Dump($_);
$_ = "\x30" x 26;
Dump($_);
[download]

Prints:

$VAR1 = "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0";
$VAR1 = '00000000000000000000000000';
[download]