One simple example can be worth a thousand words.

#!/usr/bin/perl
$text_a = "\xca\xc0\xbd\xe7\xc3\xb3\xd2\xd7\xd7\xe9\xd6\xaf\x0a";
print $text_a;

$text_b = "cac0bde7c3b3d2d7d7e9d6af0a";
print $text_b,"\n";


$text_c = pack "H*", $text_b;
print $text_c;
# and to convert back:
$text_d = unpack "H*", $text_c;
print $text_d,"\n";
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