Instruct: Classify Amazon reviews into positive or negative sentiment
Query: A wonderful reference book about Unix OS

Let me start off by saying that if you are looking for a introductory book about Unix and you have no experience with Unix OS whatsoever, this is not a book for you. If you are new to Unix OS, then you should consider buying the O'Reilly book,"Learning the Unix Operating System."Like the cover page says, this book is a reference book. This book covers GNU/Linux OS, Mac OS, Solaris OS, Unix commands, Bash Shells, Korn Shells, package management, emacs editor, and many other information that are very useful to Unix programmers, system administrators, and Unix users.If you have a bit of experience with Unix, this book should be a must.