Versions of Unix

Before we get too involved in this book, there is one thing that needs to be made clear: There are many versions of Unix, also called flavors or distros (short for distributions). In this book, all versions will be referenced as "Unix" unless there is something specific that needs to be said about a certain version or distribution. Since Unix, Linux, and all its cousins are so similar, they are said to be in the same family, but as you know, people in your family don't all look or act the same, do they? Nonetheless, you can think of Unix as a family of sorts, one with a great heritage, many grandparents, and plenty of recorded history to laugh about.

This book (just like the first edition) has been written to be as general as possible and to not favor any one vendor or implementation. This way, you can learn in the least confusing way possible; after all, the more complications you are exposed to while learning, the more your learning progress is hindered. Again, in this book, Unix is Unix unless otherwise noted.

If something in an example doesn't work on your system, don't be alarmedcheck the online manuals or ask other users of your machine. Different versions of Unix sometimes have slightly different versions of commandsit will be worth your time to learn how things work on your system as well as how things work on other distributions of Unix.