Sebastopol, CA--What exactly is Unix? It's a simple question, but it leads to a long and complicated explanation. Because Bell Labs made the system's code available for a fee, so many variations emerged by the mid-1980s that the so-called "Unix wars" broke out among proponents who wanted their version to become the accepted Unix standard. Then along came the "Unix-like" options, Linux and Mac OS X, which rival conventional Unix systems in popularity. While it's nice to have plenty of options, how do you compile a reference guide to Unix commands that covers all of these variants?

"In many ways, 'Unix is Unix' and once you understand the Unix mindset, you can be productive on almost any system," comments Arnold Robbins, author of the latest edition of longtime bestseller "Unix in a Nutshell" (O'Reilly, US $34.95). "Multi-vendor Unix systems are a fact of life. What has changed is the increased prominence of open source and free software-based systems such as GNU/Linux and Mac OS X, as well as the variations of BSD Unix."

For the fourth edition of "Unix in a Nutshell," Robbins rewrote the book to cover a cross section of the Unix world today, "one that describes what makes a Unix system a Unix system," he says. "GNU/Linux and Mac OS X are now mainstream Unix systems, even though they're not derived from the original Unix code base. They deserve equal treatment along with traditional Unix systems. I think the everyday Unix and GNU/Linux user will want this book nearby, and the Mac OS X user who is willing to see what's under the hood will be pleasantly surprised, too."

Written for system administrators, developers, and the growing ranks of power users, the book is a detailed reference to Unix commands and shells, text editing and processing tools, and software development tools common to Solaris 10, Fedora GNU/Linux Core 3, and Mac OS X 10.4 (Tiger), along with the most important commands and options specific to these systems.

Chapter 16, "The GNU make Utility," is available online at:
http://www.oreilly.com/catalog/unixnut4/chapter/index.html