In this new post on Richard Davey's blog today, he posts for one reason - to show you what to watch out for in other people's code.

There are millions of lines of PHP code freely available to download from the Internet, but how can you tell if the script you are about to install is going to send your site into oblivion or code nirvana?

In this article we get our pick axes ready, delve deep and bring back examples that serve one purpose: to show you what to look out for in other peoples code. By looking at good, bad and just downright ugly snippets of code you can gain a far better understanding of the overall quality of a PHP script.

It's a good-szied article (about 9 pages long), and provides tons of great "gotchas" to look for in the scripts that you download/integrate into your sites. Topics include: knowing what PHP version you're running, the register globals issue, the dangers of "chmod 777", and SQL injections/escaping...