I'm sure that I'm not posting this to the proper forum, but I'm not sure where the best one would be for this type of question.

I'm pretty good at using PHP and some MySQL, but I have no knowledge of using Linux or Apache, or what they can even do. I know that I need these skills to better my career, but every search that I do doesn't seem to help in trying to learn how to start out with these techniques.

Can someone help point me in the right direction on how to go about starting to learn Apache and Linux, as well as how I can practice what I've been learning?