UNIX clearly explained

Unix Clearly Explained is a complete tutorial introduction to the use and programming of the Unix operating system. Unix is known as one of the most flexible operating systems, and one of the most difficult to master. To many potential users, Unix can appear outright hostile. Much of this hostility is the result of disorientation that occurs when a user is faced with a multitude of commands. As you begin to learn Unix, it is very easy to become lost, resulting in a situation where you have little or no idea of how anything works. This text presents a working model for the major features of Unix. Once you have a familiar model to work from, it is easy to explore the many features of Unix in depth, as needed. Once you know Unix, you will find it intriguingly powerful and versatile.