Building a blog category tagging system with just PHP, HTML, and some shell scripting

Last week I had some extra time to burn and figured it was time to make a category tagging system for the blog. If anyone reading are familiar with blogs and blogging, a category system is a pretty common staple for navigating and discovering past written blog posts. For example, let's say you want to read my posts on antiques, or perhaps on Linux, you'd have to either scour thru the index or use the search form. Search forms can be useful, but if you don't specifically know what you're looking for, then they lose their purpose. I've always wanted a category system for CozyNet, but because of how I've made this site, there isn't anything ready-made or off the shelf that I could integrate that would auto-magically work without completely over-hauling the site which is not an option, so I have to make it myself! And lemme tell you, it's quite a snazzy little system. You can check it out here, or by clicking the "Categories" button on the main blog page. I don't yet have every blog post…