PHP: Hypertext Preprocessor (PHP) and Content Management Systems (CMS)
Read about PHP and Content Management Systems
Description of PHP
PHP is a scripting language used mainly for generating dynamic content in web pages. The script runs on the server which makes it independent of different browsers. After processing the PHP code, output is sent from the server to the browser in the form of an HTML page.
The PHP manual is here: http://php.net/
Resources
Quakenet PHP tutorial. Originally written in German, there is now an English version, too: http://tut.php-quake.net/en/
"Practical PHP Programming" by IT journalist Paul Hudson whose name has mysteriously disappeared from the tutorial: http://www.tuxradar.com/practicalphp
Description of CMS
Content Management Systems are used to enable people writing content for the web easily. Usually, there is a web based interface with text fields, often accompanied by a WYSIWYG (What you see is what you get) editor. This means text can be edited similarly to a word document. The CMS also allows to create new pages or content elements, and there can be other features like creating content in different languages. Also, the functionally can be extended by installing "modules" or "extensions". Not all CMS are easy to use at first sight. In fact, most of them need quite a bit of training to use them properly. There are innumerable different CMSs around, and a lot of them are free.
Resources
A place to compare different CMSs (and get an impression how many there are!) is this: http://www.cmsmatrix.org/
My experience with CMSs
The reason why for the moment PHP and CMS are on the same page is that I intend to learn how to use the current CMS of my choice, Silverstripe, and learn PHP at the same time. I think I might learn PHP from a book or online resource by directly coding it in an editor, but I will at the same time build sites (which I have already done) in Silverstripe, using PHP to customize the system. This website is also built on Silverstripe!
The only other CMS that I have really taken a closer look at is TYPO3. This is an extremely powerful "Enterprise CMS" which is used by a lot of big companies in Germany. It has a very steep learning curve. Looking back I find it kind of crazy that I used it to set up the site for our German Saturday school. I also bought the official TYPO3 book and started to slowly climb that curve. But then I realised it is not used very much here in the UK, and also, that for most of my purposes more light-weight solutions would do. Still, it does a very good job for maintaining our site, it is easy for people to edit text, and it has native support for multiple languages.
Up to now, I have somehow managed to avoide the ubiquitous Wordpress. I do have an installation sitting somewhere but have not used it beyond first tests.