Really clear and useful tutorial, thank you! I have no questions.

I plan to take this idea and extend it into a URL shortener/redirect service as a project.

1) I am making an URL shortener project. Like Bitly.com.
2) Pretty sure I can have the LAMP stack create a flat file and then Apache will access the file for redirects.
3) Reading DBM syntax now in the Apache docs for DBM hash.
4) Benefitted so far from a long thread about implementing a shortener at StackOverflow. And which chars to use, also at Stack.
5) My project is only half built (taking much longer than the three days I budgeted!). Will see if DBM mapping in Apache works.