PHP Installer Script [duplicate]

Answer 1

I would strongly recommend just copyomg the installer from the program you like the most. As I started reading your question, the first one to pop to mind was Wordpress. Then I saw your mention :-) You are on the right track.

Another two good ones to copy are: SilverStripe and OpenX.

Answer 2

I've made my own installer script and here are my tips.

1. Make sure to validate that the script will run (file & db permissions)
2. Make sure the folders/files/db structure isn't already present (if the script has run before)
3. If that's the case, make sure to have an option to remove these files
4. Always keep in mind that the user/script can fail everywhere and it should always be possible to start over