Authors: Brian Kernighan & Rob Pike
Paperback: 357 pages
Publisher: Prentice-Hall; 1st edition (November 11, 1983)
The canonical description of the Unix environment for the versions around the 7th Edition and 32V. This book is still one of the clearest descriptions of Unix and how to use it. It covers basic Unix use, shell programming, Unix filters, standard I/O and system calls via C, and nroff document processing. This is a classic text and a collector's item.
Amazon says: Designed for first-time and experienced users, this book describes the UNIX® programming environment and philosophy in detail. Readers will gain an understanding not only of how to use the system, its components, and the programs, but also how these fit into the total environment.
Someone has a scanned PDF of this book on-line.