Just curious... what book are you using and how old is it? What version of PHP does it seem to focus on?
If it's an old one, you might run into a few more things that don't work they way you'd expect.
Some of the books out there are somewhat outdated, or at least some editions are. You could search for your book title at amazon.com and see if the current edition is the same as yours.
PHP, MySQL & hosting in general constantly change/evolve, so it's good to learn as much as possible, but also from an up-to-date source.
PHP.net's manual is one of the best places to look for info. When you look up something there, you get the official explanation, a few examples, plus a bunch of user comments.
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