a  A string with arbitrary binary data, will be null padded.
 A  A text (ASCII) string, will be space padded.
 Z  A null-terminated (ASCIZ) string, will be null padded.
 C  An unsigned char (octet) value.

##</code><code>##

use Data::Dump;
my $data = "\x01\x02\x03\x20\x00";
dd unpack 'C*', $data;       # prints (1, 2, 3, 32, 0)
dd unpack 'a*', $data;       # prints "\1\2\3 \0"
dd unpack 'A*', $data;       # prints "\1\2\3"
dd unpack 'Z*', $data;       # prints "\1\2\3 "
dd unpack 'Z*', $data."X ";  # prints "\1\2\3 "
dd unpack 'A*', $data."X ";  # prints "\1\2\3 \0X"
dd unpack 'a*', $data."X ";  # prints "\1\2\3 \0X "