Introduction

• CGI programming. The basics of how a script runs, and how it interacts with its environment and the user.
• CGI Security CGI scripts are run when the user wants to, and can be fed arbitrary (malicious) input. How to program defensively.
• CGI Debugging CGI scripts are normally hard to debug, because the usual techniques often produce no output at all. Here are a few tricks.

You need some practical experience with perl. You can't write perl CGI programs without knowing how to write basic perl programs. CGI isn't particularly magical, but we will concentrate on the peculiar aspects of CGI, rather than on perl, itself. You should have written at least several small perl programs, and know how to use arrays, hashes, and regular expressions, know about file I/O, and know a little about object-oriented syntax.