This book will change your life.
That’s a strange thing to say about a computer book but, as sure as you are reading this
introduction, your life will be different by the time you fi nish the book. You will think
differently and you will approach problems differently.
You see, your computer is not a lifeless piece of machinery. It is a dynamic tool that
interacts with your very thought processes. Whenever you use a computer it becomes,
for better or for worse, an extension of your mind. This means that, over an extended
period of time, the computer system you use changes how you think. Indeed, we might
classify systems as mentally “good” or “bad” depending on how they affect the minds of
their users. In this sense, Unix is, without a doubt, the very best computer system ever
invented (and Linux is a type of Unix).
When you use Unix, you are not working with a machine. You are working with the
people who designed Unix. Every line and every picture you see on your monitor was put
there by a person. Every tool you use was invented by a person. Every technical term and
every concept you learn was created by a person. When you use Unix, you are interacting
with these people, just as surely as you are interacting with me as you read this page.
Unix and Linux are wonderful because they were developed by bright, creative people
who delighted in thinking well. These people were not only very, very smart; they knew
what they were doing and they loved their work. This means that, whenever you use a
Unix or Linux system, you are forging a mental relationship with some of the smartest,
most accomplished (and satisfi ed) programmers and computer scientists who ever lived.
Such a partnership can’t help but have a positive effect on you.
The fact is it really doesn’t matter why you want to learn Unix or Linux, or why you
picked up this book. Perhaps you love computers and you have a burning desire to learn.
Perhaps you are taking a class and this will be your textbook. Perhaps you have a job and
you are required to use Unix or Linux. It doesn’t matter.
A PERSONAL NOTE
FROM HARLEY HAHN
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You are about to begin a long, complex, and very rewarding journey. In the days,
weeks, and months to come, you will encounter new ideas and build new skills, far
beyond anything you can imagine at this moment. As you do, your mind will change for
the better, your thought processes will improve, and your way of looking at the world and
at yourself will change.
This is not your average computer book. (I’m sure you realize that by now.) Aside
from a large amount of technical material, there are hints, jokes and a lot of plain-spoken
advice. I did the very best I could to show what you really need to know. This is not a
computer manual. This is not a compendium of impersonal details. This is one person
(me) talking to another person (you).
I will make you a promise. As you teach yourself Unix, I will be with you, every step of
the way. What you are holding in your hand is my guide to learning Unix and Linux, and
now it is yours.
Are you ready?
Good. Turn to page 1 and start reading.
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Harley Hahn
GUIDE TO
Unix and Linux
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HARLEY HAHN’S GUIDE TO UNIX AND LINUX
Published by McGraw-Hill, a business unit of The McGraw-Hill Companies, Inc., 1221 Avenue of the Americas,
New York, NY 10020. Copyright 2009 by Harley Hahn. All rights reserved. No part of this publication may be
reproduced or distributed in any form or by any means, or stored in a database or retrieval system, without the
prior written consent of The McGraw-Hill Companies, Inc., including, but not limited to, in any network or
other electronic storage or transmission, or broadcast for distance learning.
Some ancillaries, including electronic and print components, may not be available to customers outside the
United States.
The name “Harley Hahn” is a registered trademark of Harley Hahn.
This book is printed on acid-free paper.
1 2 3 4 5 6 7 8 9 0 DOC/DOC 0 9 8
ISBN 978-0-07-128397-7
MHID 0-07-128397-8
www.mhhe.com
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