Mastering linux, second edition

CONTENTS AT A GLANCEPart I: Welcome to Linux Part II: Installing Linux Part III: Using Desktop Environments in Linux Chapter 7: Installing and Configuring X Windows 109 Chapter 9: Using

Arman Danesh

Michael Jang

SYBEX®

mdeltree msdosdirectory [msdosdirectory ]

The mdeltree command deletes one or more MS-DOS

directo-ries It is similar to the DOS DELTREE command.

mkdir

mkdir [-p] [-m mode] [ parents] [ mode=mode]

➥ [ help] [ version] directory

The mkdir command creates one or more directories.

more

more [-dlfs] [ number] [+number] [file ]

The more command displays one or more files,

screen-by-screen, and allows for searching and jumping to an arbitrary

location in the file.

mount

mount -a [-rvw] [-t vfstype]

mount [-rvw] [-o options [, ]] device | dir

mount [-rvw] [-t vfstype] [-o options] device dir

The mount command mounts a file system to a specified directory.

nslookup

nslookup [host | - [server]]

The nslookup command queries a DNS name server It can be

run in interactive mode If no host name is provided, then the

program enters interactive mode By default, the DNS server, as

specified in /etc/resolv.conf, is used unless otherwise

speci-fied If you want to specify a server but not look up a specified

host, you must provide a - in place of the host.

passwd

passwd [-S] [-d delim-list] [file ]

The passwd command changes a user’s password When run by

the root user, it can be used to change a specific user’s password

by providing the username as an argument.

ping

ping [-fR] [-c number] [-i seconds]

➥ [-s packetsize] host

The ping command sends echo request packets to a network

host to see if it is accessible on the network.

ps

ps [lumaxwr] [txx] [pid ]

The ps command displays status reports for currently running

processes Given a specific process ID as an argument, ps

dis-plays information about that particular process Without

options or arguments, ps displays the current user’s processes.

rmdir [-p] [ parents] directory

The rmdir command deletes empty directories.

rsh

rsh [-Knx] [-l username] host [command]

The rsh command opens a shell on a remote system If a mand is provided, the command is executed on the remote host, the results are returned, and the connection is terminated.

tar

tar [-crtuxz] [-f file] [ file file] [ create]

➥ [ delete] [ preserve] [ append] [ same-owner]

➥ [ list] [ update] [ extract] [ get] [ gzip]

➥ [ ungzip] [file | directory ]

The tar command creates an archive file of one or more files or directories.

unzip [-cflptuz] file[.zip]

The unzip command manipulates and extracts ZIP archives.

zcat

zcat [-f] [file ]

The zcat command uncompresses one or more compressed files and displays the results to the standard output If no files are specified, then the standard input is uncompressed and displayed.

zip

zip [-efFgmrSu@] [ zipfile [ file1 file2 ]]

The zip command creates a ZIP archive from one or more files and directories.

zmore

zmore [file ]

The zmore command displays the contents of compressed text files, one screen at a time, allowing searching in much the same way as the more command If no files are specified, the standard input will be used.

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Mastering Linux

Second Edition

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Mastering™ Linux

Second Edition

Arman Danesh

and Michael Jang

San Francisco • Paris • Düsseldorf • Soest • London

Associate Publisher: Dick Staron

Contracts and Licensing Manager: Kristine O’Callaghan

Acquisitions and Developmental Editor: Ellen L Dendy

Editor: Linda Recktenwald

Production Editor: Leslie E.H Light

Technical Editor: Baruch A Mettler

Book Designer: Kris Warrenburg

Graphic Illustrator: Tony Jonick

Electronic Publishing Specialist: Judy Fung

Proofreaders: Nanette Duffy, Emily Hsuan, Laurie O’Connell, Yariv Rabinovich, Nancy Riddiough

Indexer: Ted Laux

Cover Designer: Design Site

Cover Photographer: Jack D Myers, Design Site

Copyright ©2001 SYBEX Inc., 1151 Marina Village Parkway, Alameda, CA 94501 World rights reserved No part of this publication may be stored in a retrieval system, transmitted, or reproduced in any way, including but not limited to photocopy, photograph, magnetic or other record, without the prior agreement and written permission of the publisher.

Library of Congress Card Number: 2001088247

ISBN: 0-7821-2915-3

Screen reproductions produced with either The GIMP (a graphics package included with Red Hat Linux 7) or Capture Express 2000 Capture Express 2000 is a trademark of Insight Software Solutions Inc.

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Many thanks to the GNU and Linux community

of developers, who are constantly proving that a group of volunteers can compete with

the biggest software companies.

Computer books, even revisions, are a group effort As an author, I am only asmall part of this First, let me thank the original author, Arman Danesh, for listen-ing to my input during the development of this revision The people whom Sybexbrought together on this book are a well-oiled team Leslie Light made sure that theproject stayed on track in every detail Linda Recktenwald brought diverse inputstogether and added her own common sense to the final product Baruch Mettlerthoroughly tested everything in the book, helping to make sure that everything will work for you The book could not go to press without the gracious efforts ofthe other members of the team, including Dick Staron, Kristine O’Callaghan, JudyFung, Nanette Duffy, Emily Hsuan, Laurie O’Connell, Yariv Rabinovich, NancyRiddiough, and Ted Laux

Thanks especially goes to Ellen Dendy, for bringing us together on this venture,making sure that everything went smoothly with the rest of the team

On the home front, thank you, Nancy, for your constant love and support

CONTENTS AT A GLANCE

Part I: Welcome to Linux

Part II: Installing Linux

Part III: Using Desktop Environments in Linux

Chapter 7: Installing and Configuring X Windows 109

Chapter 9: Using Applications with GNOME and X Windows 161

Chapter 12: Advanced X Windows Configuration 259

Part IV: Mastering the Essentials

Chapter 15: Using LinuxConf and Other Tools for System

Configuration 333

Part V: Basic Connectivity

Chapter 22: Connecting Linux to the Internet 495

Part VI: Using Linux in the Small Office/Home Office (SOHO)

Chapter 28: Configuring Linux for an Ethernet Network 615Chapter 29: Integrating Linux in Windows and Novell Networks 643

Chapter 31: Security and Linux As an Inexpensive Router 685

Part VII: Using Linux As a Web and E-Mail Server

Chapter 33: Linux As a Mail Server: The Power of Sendmail 787

Appendices

Appendix A: Linux around the World (Non-English Linux

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Checking Your Hardware for Compatibility 32

Sound Cards 34Monitors 34Mice 35

A Sample Partition Scheme for a Windows 98 System 40

5 Special Installations 69

X Servers, Window Managers, and

Contents xvii

Preparing to Configure X Windows 116

8 Using GNOME and X Windows 137

9 Using Applications with GNOME and X Windows 161

Running an Application in an Xterm Window 171

10 Advanced GNOME Configuration 193

Desktop 196

Multimedia 204Peripherals 205

Session 209

Contents xix

Using Multiple Desktops 233

12 Advanced X Windows Configuration 259

The XF86Config File 260

The xinitrc File 279 The Xclients File 282

PART IV: Mastering the Essentials 289

13 Introducing Linux Commands 291

pwd, cd, and ls 295

find, locate, and grep 300

14 Working with Files 315

Moving and Renaming 326

A Quick Introduction to Filename Expansion 330

The Tests Menu 337

Changing useradd Defaults 386

The init Program 392 Using the rc.local File 395

How crond Works 397

PCI 411External 411USB 412Printers 412

The printcap File 414

Modems 425

Contents xxiii

20 Recompiling the Linux Kernel 455

PART V: Basic Connectivity 481

21 Understanding Linux Networking 483

23 Using the World Wide Web 517

Amaya 519Lynx 520Opera 521Mosaic 522

Contents xxv

Installing from the Web 524

25 Faxing from Linux 571

PART VI: Using Linux in the Small Office/Home Office (SOHO) 587

26 Where to Use Linux in the SOHO 589

Linux As an Intranet Server 593

27 Installing Linux for the SOHO 601

28 Configuring Linux for an Ethernet Network 615

Contents xxvii

29 Integrating Linux in Windows and Novell Networks 643

Sharing Linux Files and Printers with Windows Networks 644

30 Linux and DOS/Windows 663

31 Security and Linux As an Inexpensive Router 685

Configuring Basic Network Settings 697

Part VII: Using Linux As a Web and E-Mail Server 703

32 Building Your Own Web Server 705

Apache 710NCSA httpd 710W3C/Jigsaw 711

WN 712Boa 712Stronghold 713FastTrack/iPlanet 713AOLserver 714

Zeus 715

Contents xxix

33 Linux As a Mail Server: The Power of Sendmail 787

Smail 789Qmail 790

C Linux Command Reference 817

D GNU General Public License 893

Terms and Conditions for Copying, Distribution, and Modification 895

Appendix: How to Apply These Terms to Your New Programs 900

E Linux on Non-Intel Hardware 903

Contents xxxi

Thank you for buying this book, and welcome to the world of Linux As one

of the few alternatives to Microsoft operating systems on affordable desktop-classpersonal computers, Linux has gained notoriety and, more recently, acclaim as anexample of what can be done by a group of motivated people without any fiscalincentive

Linux is a freely distributable, efficient, fast operating system that offers thepower of Unix—once the domain of expensive servers and workstations—onhardware affordable to the budget-conscious home computer user This hassparked a mini-revolution in the computer world leading to acceptance of freesoftware for a wide range of tasks—from mission-critical Web sites to corporateinformation systems infrastructure to education applications

This book is designed as an introduction to the installation and use of Linuxbased on Red Hat Linux 7 Red Hat Linux 7 is a widely used version of Linuxthat is well suited to use on server systems, as well as Linux workstations anddesktop computers Any operating system with the breadth of features andcapabilities offered by Linux cannot be covered completely in a single book Still,this book provides the sound knowledge of Linux, and Red Hat in particular,needed for users to move on and learn more on their own as they use Linux intheir everyday work

Who Should Read This Book?

This book is really designed for anyone who uses a PC Although Linux may notyet have all the ease-of-use refinements found in commercial desktop operatingsystems such as Windows 95/98/Me and the Mac OS, Linux can be used byalmost anyone and mastered by anyone who can master Windows

Having said that, learning to use any operating system is always easier if youalready possess some basic computer knowledge, including an understanding ofthe difference between a hard disk and RAM, an understanding of the basic con-figuration (in Windows) of peripherals such as video cards and sound cards, and

If you are already comfortable using a Windows or Macintosh system and youhaven’t experimented with the DOS prompt, it would be helpful to do so beforediving into the world of Linux, where the command line is more powerful, andtherefore more heavily used, than in the Windows arena.

If you are already a power user of Windows, then you are more than ready tobecome a power user of Linux Just as this book will make the everyday com-puter user proficient at getting their work done using Linux, it will help youbecome an advanced Linux user

This book also has something to offer for the SOHO (Small Office/Home Office)user or manager of a small network You will learn how to use Linux in many situ-ations in your office environment, in roles that include file server, intranet Webserver, and router

What You Need to Use This Book

To use this book, you will need access to a personal computer with the followingminimum specifications:

• A Pentium CPU or higher (In theory, you can run Linux on a 386 system, butthe performance will likely be poor enough that it isn’t worthwhile for mostusers.)

• 32MB of RAM or more (You will notice a significant performance gain ifLinux has 64MB or more of memory.)

• A hard disk with at least 1GB of free disk space (If you can afford 2GB ormore, this will greatly enhance your freedom to experiment with Linux andLinux applications.)

• A CD-ROM drive (preferably an ATAPI/IDE CD-ROM or SCSI CD-ROMdrive)

• A backup of your current system in case you need to recover existing data

or applications

• A video card and VGA or better monitor

• A keyboard and mouseYou may also want to have the following options:

• A printer (Opt for a PCL or PostScript printer if you have a choice.)

• A sound card and speakers

• A telephone modem, ISDN modem, or other high-speed connection

How This Book Is Organized

This book is divided into seven sections:

Welcome to Linux This section introduces you to Linux as an operatingsystem and as the foundation of the GNU General Public License softwaremodel It looks at the most popular distributions (versions) of Linux andhelps you make preparations to install Linux on your system

Installing Linux This section covers the installation of a stand-alone Linuxsystem It includes a discussion of how to prepare to install Linux and spe-cial installations (such as on systems with no CD-ROM drive)

Using Desktop Environments in Linux This section looks at the use

of X Windows with the GNOME desktop manager (the standard Red HatLinux GUI) This discussion includes an overview of some common X Win-dows applications

Mastering the Essentials This section describes a range of essential skillsneeded to truly master Linux Topics covered include file management, sys-tem configuration, and printers and peripherals

Basic Connectivity This section explains how to connect a Linux system

to the Internet using a dial-up connection Topics covered include accessingthe World Wide Web and working with e-mail

Introduction

Using Linux in the SOHO As an inexpensive but powerful computingenvironment, Linux is well-suited to many small or home office tasks Thissection looks at the installation of Red Hat Linux 7 in a networked officeenvironment and the use of Linux as a file or print server for Unix and Win-dows networks and will give you an awareness of basic security issues whenusing Linux in a networked environment Finally, this section examines DOSand Windows compatibility and integration in Linux, which allows manyorganizations to migrate from their current Windows environments to Linuxwithout sacrificing their current investment in software and applications

Using Linux As a Web and E-Mail Server In addition to being an ideal fileand print server for the SOHO, Linux can be used to create robust enterpriseWeb and mail servers This section describes how to set up Linux-based Weband mail servers

If you already have some experience with Linux, you probably can skip straight

to the second section of the book, “Installing Linux,” and begin installing a Linuxsystem If you have never used Linux before, start at the beginning with “Welcome

to Linux” to get your feet wet and become comfortable with the world of Linuxand its dynamic nature Whatever your background, though, always rememberthat computers are tools that bring added power to your work, and Linux is agreat way to enhance that role

P A R T I

■ CHAPTER 1: What Is Linux?

■ CHAPTER 2: Choosing a Distribution

Welcome to Linux

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C H A P T E R

O N E

What Is Linux?

■ Linux History

■ Linux as an Operating System

■ Linux as Free Software

■ Commercial Applications for Linux

1