Welcome! This is a book about the Red Hat Package Manager, or RPM Package Manager, known to its friends as simply RPM. The history of RPM is inextricably linked to the history of GNU/Linux, so a bit of GNU/Linux history may be in order. GNU/Linux is a full-featured implementation of a UNIX-like operating system, and has taken the computing world by storm.

And for a good reason — When choosing GNU/Linux, an Intel-based personal computer that had previously been prisoner of the dreaded Windows hourglass is transformed into a fully multitasking, network capable, personal workstation. All for the cost of the time required to download, install, and configure the software.

Of course, if you're not the type to tinker with downloaded software, many companies have created CDROMs containing GNU/Linux and associated software. The amount of tinkering required with these distributions has varied widely. The phrase "You get what you pay for" is never more true than in the area of GNU/Linux distributions.

One distribution bears the curious name "Red Hat Linux". Produced by a company of the same name, this GNU/Linux distribution was different. One of the key decisions a new Linux user needs to make is which of the many different parts of the distribution to install on their system. Most distributions use some sort of menu, making it easy to pick and choose. Red Hat Linux is no different.

But what is different about Red Hat Linux is that the creators of the distribution wanted their customers to have the the ability to make the same choices long after the installation process was over. Some commercial UNIX systems have this capability (called "package management"), and a few GNU/Linux distributors were trying to come up with something similar, but none had at the time the extensive scope present in RPM.

Over time, Red Hat Linux has become the most popular distribution available today. For it to edge out the previous leader (Slackware) in just two years is amazing. There has to be a reason for this kind of success, and a good part of the reason is RPM. But until the first edition of this book, there had been precious little in terms of RPM documentation. You could say that RPM's ease of use has made detailed instructions practically unnecessary, and you'd be right.

However, there are always people that want to know more about their computers, and given the popularity of Red Hat Linux, this alone would have made a book on RPM worthwhile. But there's more to the story than that.

There is a truism in the world of Free Software, that goes something like this: If there's a better solution freely available, use it! RPM is no exception to the rule. Put under the terms of the GNU General Public License (Meaning: RPM cannot be made proprietary by anyone, not even Bill Gates), RPM started to attract the attention of others in the Linux, Unix, and free software communities.

At present, RPM is used by several commercial software companies producing Linux applications. They find that RPM makes it easier to get their products into the hands of their customers. They also find that it can even make the process of building their software easier. (Those of you that develop software for fun and profit, stick around — the second half of this book will show you everything you need to know to get your software "RPM-ized")

People have also ported RPM to several commercial UNIX systems, including DEC's Digital Unix, IBM's AIX, and Silicon Graphics' IRIX. Why? The simple answer is that it makes it easier to install, upgrade, and de-install software. If all these people are using RPM, shouldn't you?

This book is divided into two major sections. The first section is for anyone that needs to know how to use RPM on their system. Given the state of the GNU/Linux arena today, this could mean just about anyone, including people that are new to GNU/Linux, or even UNIX. So those of you that think that

ls -FAl !* | less
        

is serious magic (or maybe even a typing error), relax — we'll explain everything you'll need to know in the first section.

In the book's second half, we'll be covering all there is to know about building packages using RPM. Since software engineering on GNU/Linux and UNIX systems requires in-depth knowledge of the operating system, available tools, and basic programming concepts, we're going to assume that the reader has sufficient background in these areas. Feel free to browse through the second half, but don't hesitate to seek additional sources of information if you find the going a bit tough.

Writing a book is similar to entering a long-term relationship with an obsessive partner. Throughout the nine months it took to write this book, life went on: job changes, births, deaths, and even a hurricane. Throughout it all, the book demanded constant attention. Therefore, I'd like to thank the people that made it possible to focus on the book to the exclusion of nearly everything else. My wife, Deb and son, Matt supported and encouraged me throughout, even when I was little more than a reclusive houseguest hunched over the computer in the study. Additionally, Deb acted as my editor and indexer, eventually reading the book completely three times! Thank you both.

Thanks also to Marc Ewing and Erik Troan, RPM architects extraordinaire. Without their programming savvy, RPM wouldn't be the elegant tool it is. Without their boundless patience, my many questions would have gone unanswered, and this book would have been much less than it is now. I hope you find this book a worthy companion to your programming handiwork.

Rik Faith provided some much-needed information about PMS and PM, two of RPM's ancestors. Thank you!

Finally a great big thank you goes to Jessica and the gang at L'il Dinos, Jennifer and her crew at the Cary Barnes & Noble coffee shop, and Mom and her "kids" at Schlotzsky's Deli in Durham. If all of you hadn't let me sit around for hours writing, this book wouldn't be nearly as fat as it is. And neither would I!

February, 1997 Cary, North Carolina