Its a very extensive book that covers concepts and advanced features of UNIX. It covers UNIX implementation of different features as a user point of view and how to access diffent services of UNIX like OSs. If you want to learn UNIX /Linux based programming this book a must read & must have for reference. I highly recommend this book

I occasionally need to fix broken IPC code and figure out behavior differences
of legacy code between Solaris, Linux, etc., code written years ago by somebody
else in C.

This book, (and Stevens' earlier books before this) has been immensely useful.
The code samples alone are worth their weight in gold :-). Seriously, this book
has saved me many days of hard work, several times over.

A quick browse of the book is usually enough to find the details (what I would
call 'arcane details', but I guess this is because I'm not an expert C/networking
programmer), figure out the problem AND how to fix the problem.

This book has been a 'project-saver'. I cannot recommend this text too highly.

This is one of the best books I've ever read about UNIX and programming.

With its unique style, it serves as both a reference and a tutorial, and at the same time, it provides amazing detail and insight, always making the reader understand what's happening "under-the-hood". Fantastic job, Steven Rago and Richard Stevens!

The only problem I had with this book was with the source code. It doesn't compile under MacOS X 10.5 Leopard, which is a certified Unix 03 system. It is a only a one-line change in the includes, so it's no big deal.

This book is literally saving me right now in an Introduction to Operating Systems class I'm taking. We have projects to complete in the UNIX envrionment and the fact that this book gives you every real code example you could possibly need for all levels of systems programming is GOLD. It's laid out in a very straightforward way, has tons of code examples, and is overall awesome. Highly recommend if you're just getting into systems programming on your own, or as a school reference book.

This book is a fantastic starting point in life. Some how our public schools over look teaching the fundamental skills presented in this book. We learn how to play with toys on simple computers and never really learn what we are doing.

The real strength of this book is in the definitions. We get to see the purpose and flexibility of system calls and functions. Not just use them but understand them. UNIX functions as job control or signals are explained in detail. Let's take just one item "waitpid":

The waitpid function provides three features that aren't provided by the wait function.

You will have to red the book to find out what they are. However there are examples also. Now for people with real systems like AIX all you have to do is ad a "k" to the front of the call and you have the AIX kernel function call "kwaitpid"; voila you now have an understanding that can not be found clearly in a Red Book.

It does help some to have a preunderstanding of the system do you can use the book to fill in the education holes missed when necessary.

The index is worth its weight in gold as you can find functions headers and concepts all in alphabetical order. My favorite is the definitions.

As much as I am a fan of the internet it also pays to carry the information in the form of a book. And all this book has to do is save a couple of hours and it has paid for its self.

Mastering UNIX Shell Scripting