Admin Linux

Red Hat Linux

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POCKET ADMINISTRATOR
Richard Petersen Ibrahim Haddad

McGraw-Hill/Osborne
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McGraw-Hill/Osborne 2100 Powell Street, 10th Floor Emeryville, California 94608 U.S.A. To arrange bulk purchase discounts for sales promotions, premiums, orfund-raisers, please contact McGraw-Hill/Osborne at the above address. For information on translations or book distributors outside the U.S.A., please see the International Contact Information page immediately following the index of this book.

Red Hat Linux Pocket Administrator
Copyright © 2003 by The McGraw-Hill Companies. All rights reserved. Printed in the United States of America. Except as permittedunder the Copyright Act of 1976, 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 permission of publisher, with the exception that the program listings may be entered, stored, and executed in a computer system, but they may not be reproduced for publication. Publisher Brandon A. NordinVice President & Associate Publisher Scott Rogers Acquisitions Editor Francis Kelly Project Editor Julie M. Smith Jessica Wilson Acquisitions Coordinator Technical Editor Ibrahim Haddad Copy Editor Brian MacDonald Proofreader Susie Elkind Indexer Richard Shrout Composition Tara A. Davis, Lucie Ericksen Illustrator Lyssa Wald Series Design Peter F. Hancik, Lucie Ericksen, Elizabeth Jang Cover SeriesDesign Jeff Weeks 1234567890 DOC DOC 019876543 ISBN 0-07-222974-8 This book was composed with Corel VENTURA™ Publisher.
Information has been obtained by McGraw-Hill/Osborne from sources believed to be reliable. However, because of the possibility of human or mechanical error by our sources, McGraw-Hill/Osborne, or others, McGraw-Hill/Osborne does not guarantee the accuracy, adequacy, orcompleteness of any information and is not responsible for any errors or omissions or the results obtained from the use of such information.

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To my nephew Christopher Richard Petersen

to my wonderful family, for their love and support, and to the love of my life, who brings me happiness every day Ibrahim Haddad

About the Authors
Richard Petersen teaches UNIX and C/C++ courses at theUniversity of California at Berkeley. He is the author of four editions of Linux: The Complete Reference and many other books. Ibrahim Haddad is a Researcher at the Ericsson Corporate Research division’s Open System Lab, located in Montreal, Canada. Mr. Haddad is involved with the system architecture of third generation wireless IP networks and guiding Ericsson Open Source contributions, whichpromote and advance the use of Linux in the area of telecommunication. Mr. Haddad represents Ericsson on the Technical Board of the Open Source Development Lab and serves as Contributing Editor to the Linux Journal. In addition to his contributions to the Linux Journal, Mr. Haddad writes for Linux User & Developer in the areas of IPv6 and telecommunications and has delivered a number of presentationsand tutorials at local universities, IEEE and ACM conferences, Open Source forums, and international conferences. Mr. Haddad received his Bachelor and Master degrees in Computer Science from the Lebanese American University, charted by the University of the State of New York. He is currently a Dr. Sc. Candidate at Concordia University in Montreal researching Next Generation Internet Servers.Academic awards include the “J. W. McConnell Memorial Graduate Fellowship” and the “Concordia University 25th Anniversary Fellowship,” received in 2000.

CONTENTS
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xi

1

Basic System Administration . . . . . . . . . . . . . . . . .
Superuser Control: the root user . . . . . . . . . . . . . . . . . Root User...