Hello and kudos for actually reading the README file!
First of all, thank you for your interest in my work. It is most appreciated. The file you have downloaded is associated with the book:
PHP and MySQL for Dynamic Web Sites: Visual QuickPro Guide (5th Edition) Written by Larry Ullman Published by Peachpit Press 2017 ISBN: 0-321-xxxxx-x
Second, if these scripts don't match those in the book you have, then you've most likely downloaded the wrong scripts. Each book I've written has its own section at the LarryUllman.com website. Each edition of a title also has its own section at that site. The proper URL for the book you have will normally be on the book of the book, in the book's Introduction, and frequently mentioned elsewhere within the text. Double-check that URL, then go to the corresponding website. Each page on the website also clearly states the book title and edition for which it applies.
Third, these scripts may contain minor corrections compared to those in the book, correcting a mistake found after the book was published.
Fourth, these scripts have been formatted with line breaks that will work on most systems and most text editors. If you have difficulty opening a file, including this one (for example, the formatting is all messed up), try adjusting the way your text editor treats text files or using a different text editor, if possible. In particular, Notepad on Windows is a pretty lousy text editor.
Fifth, if you have problems with these scripts, it's most likely NOT a problem with the script but rather a problem with how it's being used or the server configuration. Turn to the book's supporting forum, at LarryUllman.com/forums/, for assistance.
Finally, readers occasionally wonder about the legalities of using these scripts in active sites. The only real restriction is that, in accordance with copyright law, you cannot copy or redistribute any of the code in the book (and, therefore, any of the code in this set of downloaded files). I am not a lawyer, but I interpret this to mean you cannot literally photocopy or scan the book's pages. You also cannot make the code available to others in paper or digital form (i.e., as a downloadable or copy-able item on a server).
Beyond that restriction, I feel that you're pretty much allowed to do whatever you want. Can you actively use the code on your site? By all means. Can you use it in projects you've been hired to do? Sure. The fact of the matter is that I don't think anyone could take the code out of the book verbatim and use it on a fully-functional, live site (which is to say, I expect you'll have to do some work to adapt these scripts to your needs). If you want to give me some kind of credit, that's great. Just point people to the book or the book's corresponding website.
As always, if you have any questions, you'll get the fastest possible response by using the book's corresponding forum, found at LarryUllman.com/forums/. I also highly encourage everyone to sign up for my newsletter (see LarryUllman.com/newsletter/), to stay informed on my book news and technology updates, to win free books, to get your questions answered, and more.
Thanks, Larry Ullman www.LarryUllman.com