Some famous papers and a few books by Unix's early developers have mined this territory before. Kernighan and Pike's The Unix Programming Environment [Kernighan-Pike84] stands out among these and is rightly considered a classic. But today it shows its age a bit; it doesn't cover the Internet, and the World Wide Web or the new wave of interpreted languages like Perl, Tcl, and Python.
About halfway into the composition of this book, we learned of Mike Gancarz's The Unix Philosophy [Gancarz]. This book is excellent within its range, but did not attempt to cover the full spectrum of topics we felt needed to be addressed. Nevertheless we are grateful to the author for the reminder that the very simplest Unix design patterns have been the most persistent and successful ones.
The Pragmatic Programmer [Hunt-Thomas] is a witty and wise disquisition on good design practice pitched at a slightly different level of the software-design craft (more about coding, less about higher-level partitioning of problems) than this book. The authors' philosophy is an outgrowth of Unix experience, and it is an excellent complement to this book.
The Practice of Programming [Kernighan-Pike99] covers some of the same ground as The Pragmatic Programmer from a position deep within the Unix tradition.
Finally (and with admitted intent to provoke) we recommend Zen Flesh, Zen Bones [Reps-Senzaki], an important collection of Zen Buddhist primary sources. References to Zen are scattered throughout this book. They are included because Zen provides a vocabulary for addressing some ideas that turn out to be very important for software design but are otherwise very difficult to hold in the mind. Readers with religious attachments are invited to consider Zen not as a religion but as a therapeutic form of mental discipline — which, in its purest non-theistic forms, is exactly what Zen is.