This CoolTool is a Perl script designed to help its user learn ascii/hex/octal/decimal conversions for the most-common characters used in this page you can look up ASCII characters and descriptions.">ASCII. Printable and non-printable characters can be learned and their conversions memorized for uses in various computer applications. Utilities that utilize hex values of characters become usable, readable, and understandable. HTML encoding, complex URLs and complex regular expressions are just some of the benefits to having these conversions learned. As a side effect converting between decimal, octal, and hex is possible and that learning can take place without using the ascii functionality.
For people wanting to learn Perl this shows a basic, semi-practical use of hashes-of-hashes among other operations.