Linux and Unix are essentially two takes on the same operating system, with Linux serving as the free, open-source version.

This book is an introduction to Unix system programming with an emphasis on Linux. While it mostly focuses on the kernel's application programming interface, it also guides the inexperienced Linux user through the use of the bash shell and the most useful Unix tools, and it presents the underlying structure of the Linux kernel. The programming is entirely in C.

The author's friendly, conversational style reflects his more than 40 years of experience teaching this material. Numerous diagrams included in each chapter illustrate and simplify key concepts, while hands-on exercises help to cement lessons that build on one another through the book.

Prior programming experience, preferably in C or C++, is helpful but not required. No knowledge of Linux or Unix is necessary, but readers will need access to a Linux system.