Preface

           Preface Unix is known as one of the most flexible of operating systems, and one of the most difficult to master.  To the beginner, Unix can appear outright hostile.  Much of this hostility is the result of disorientation that occurs when a beginner 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.  Once you know Unix you will find it intriguing, powerful, and versatile.  You can do almost anything with Unix.  That is, of course, if you can get started.  This is a very big if.  It is also the aim of this text.

            Numerous texts already exist on Unix, and most now feature the popular GUI interfaces like Solaris and Gnome.  This text is designed to introduce users to the command line interface.  Unix originally supported only a command line interface.  In fact many people still find it easier to use the command line for operations. Instead of trying to figure out how to click through a GUI interface to do a certain task, you just have to type a few words.  Most books that do feature the command line, concentrate on Unix administration tasks, not user level operations. The aim of this book, however, is to open up the command line dimension of Unix to beginning users. 

            The text is organized to carefully introduce you to Unix without overwhelming you with a mass of commands and programs.  It introduces Unix in three phases, focusing first on a tutorial orientation, then essential uses, and finally on specific applications.  In Section 1, you learn how to get started with basic operations using the command line interface.  In Sections 2 and 3, you learn essential features of Unix needed to perform everyday tasks such as file management and shell operations.  Together, Sections 1, 2, and 3 form a core level of understanding that you need to have in order to successfully work with Unix.  Everyone needs to know how to configure the shell and manage directories.  Sections 4, 5, and 6 consist of topics that you can select depending on your needs, such as data and edit filters, awk programming, email, Ftp access, and editors.

            The first section is designed help you get started using basic operations such as logging into the system.

            Sections 2 and 3 consist of material that everyone needs to know for day-to-day operations.  It provides a detailed explanation of the file structure, followed by a more in-depth explanation of the shell.  You learn how to manage files and directories, creating, accessing, copying, and moving them.  You also learn how to configure Unix to meet your own needs.  Unix is a multi-user system.  Individual users have their own interface with the system that they can configure any way they want.  Such an interface is called a shell and is configured using special shell variables and commands. 

            Sections 4 and 6 present specialized filters and editors.  Section 4 focuses on advanced filters beginning with edit filters such as sed and diff.  An explanation of regular expressions follows as well as a discussion of data filters such as sort and uniq. Section 6 discusses the Vi, Ex, and Emacs editors.

            Section 5 discucsses command-line networking tools like mailx for electronic mail, ftp for FTP access and downloads, and the remote commands for remotely logging in and copying form another system.

            Throughout the text, there are tables of the most widely used commands for each feature.  The end of each chapter contains tables listing all the commands discussed in that chapter.  The last section contains a complete list of all those commands, including detailed explanations of their options. The purpose of this bookis to provide users with a practical as well as professional understanding of UNIX. UNIX can be a very difficult system to learn.  Practical difficulties such as the Vi editor are dealt with.  The primary emphasis is on the use of the system; use with understanding.