If you are a sysadmin or want to learn programming on UNIX/LINUX you must have this book. I have several books on C and several on other languages I would trade them all for this. It covers the basics (essentials) that other books written exclusively for one language don't even touch on. I explains how all of the languages covered interplay with UNIX/LINUX.

The first chapter covers programs, the C compiler, header files, staic libraries, and shared libraries. It explains they all come together to make a program in a way that it can be understood

The second chapter covers UNIX shell scripts at length. I have good book on shell scripts, and this chapter alone is just as good as that book.

The third chapter covers working with UNIX files, system calls, library functions etc... The sample programs all work as they are supposed to. Everything is clearly explained and easily understood.

The 4th chapter covers passing arguments to C programs, envorment variables, temporary files, configuring logs, and system resources.

I have not read any further, because I've only had this book a week. I've been looking for a book like this for a few years. It talks about how C and other languages interface with LINUX/UNIX rather than just giving you the pure language and leaving you to fend for yourself.

Other chapters include:
5) Terminals
6) Curses
7) Data Management
8) Development Tools
9) Debugging
10) Processes and Signals
11) POSIX Threads

12) Inter-process Communication: Pipes
13) Semaphores, Mesage Queues, and Shared Memory,
14) Socets
15) TCL: Tool Command Language
16) Programming for X
17) Programming for GNOME using GTK+
18) The Perl Programming Language
19) Programming for the Internet: HTML
20) Internet Programming 2: CGI
21) Device Drivers
Appendex A) Portability
Appendex B) FSF and the GNU Project
Appendex C) Internet Resources
Appendex D) Bibliography

If you are only get one book on programming, this is the one you need. I have at least 8 other books on various programming languages, and this one is better than all of them combined. This book is 900 pages packed full information, and it's easily understood. The sample programs all work and are well documented.

I write this review after reading only four chapters, because the information I have gotten out of them is worth way more than the price of this book. This book gives you all the pieces to the puzzles and tells you how to put it together. This book can be used by advanced programmers as well to fill in any knowlege gaps they may have. This book gets my highest recommendation, as it will be by my side for years to come.