An article about a simple CGI program that demonstrates how to access and print every environment variable from the Perl/CGI environment. Free source code. Good for debugging.

Lists all standard environmental variables made available to CGI programs by web servers, and provides a brief explanation of each one of them.

These are environment variables specific to the Apache servers which control the way Apache interacts with specific browsers.

Reference to all valid ECHO commands (returns environmental variables) to paste into your HTML document for parsing by your Apache webserver.