Data::Dumper prints it for me (Perl 5.8.8, Solaris):

perl -MData::Dumper -e '$_ = "\x00" x 4; print Dumper $_' | cat -v
$VAR1 = '^@^@^@^@';
[download]

You are correct, Data::Dumper prints the '\0' but it is only visible in the output via something like cat -v. Nice trick btw, I didn't know about that. Thank you!

-- Hofmator

Code written by Hofmator and posted on PerlMonks is public domain. It is provided as is with no warranties, express or implied, of any kind. Posted code may not have been tested. Use of posted code is at your own risk.

When you really want to see the data, try Devel::Peek:

use Devel::Peek qw(Dump);

$_ = "\x00" x 26;
print Dump($_);
$_ = "\x30" x 26;
print Dump($_);

__END__
SV = PV(0x1800884) at 0x1800514
  REFCNT = 1
  FLAGS = (POK,pPOK)
  PV = 0x3015e0 "\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"
+\0
  CUR = 26
  LEN = 27
SV = PV(0x1800884) at 0x1800514
  REFCNT = 1
  FLAGS = (POK,pPOK)
  PV = 0x3015e0 "00000000000000000000000000"\0
  CUR = 26
  LEN = 27
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or using Data::Dump::Streamer:

use strict;
use warnings;

use Data::Dump::Streamer;

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