Ubuntu The Complete Reference phần 1 pptx

Linux Features Ubuntu includes features that have become a standard part of any Linux distribution, such as the desktops, Unix compatibility, network servers, and numerous software appli

Ubuntu ® The Complete Reference

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DOI: 10.1036/0071598464

To my cousins, Ken and Carolyn

About the Author

Richard Petersen, MLIS, teaches UNIX and C/C++ courses at the University of California at Berkeley He

is the author of Linux: The Complete Reference (all six editions), Red Hat Enterprise and Fedora Linux: The Complete Reference, Red Hat Linux, Linux Programming, Red Hat Linux Administrator’s Reference, Linux

Programmer’s Reference, Introductory C with C++, Introductory Command Line Unix for Users, and many

other books He is a contributor to linux.sys-con.com

(Linux World Magazine) with articles on IPv6, Fedora

operating system, Yum, Fedora repositories, the Global File System (GFS), udev device management, and the Hardware Abstraction Layer (HAL)

About the Technical Editor

Ibrahim Haddad is director of technology at Motorola, Inc., where he is responsible for defining and developing the requirements for Motorola’s open source initiatives Prior to his work at Motorola, he managed the Carrier Grade Linux and Mobile Linux Initiatives at the Open Source Development Lab (OSDL), which included promoting the development and adoption of Linux and open source software in the communications industry Prior to joining OSDL,

he was a senior researcher at the Research &

Innovation Department of Ericsson’s Corporate Unit

of Research He is contributing editor of the Linux Journal and the Enterprise Open Source Magazine

Haddad received his B.Sc and M.Sc degrees in Computer Science from the Lebanese American University, and earned his Ph.D in Computer Science from Concordia University in Montreal, Canada In

2000, he was awarded by Concordia University both the J W McConnell Memorial Graduate Fellowship and the Concordia University 25th Anniversary Fellowship in recognition for academic excellence In

2007, he was the winner of the Big Idea Innovation Award in Recognition of Leadership and Vision at Motorola Inc

Copyright © 2009 by The McGraw-Hill Companies Click here for terms of use

Contents at a Glance

Part I Getting Started

1 Introduction to Ubuntu 3

2 Installing Ubuntu 17

3 Interface Basics: Login, Desktop, and Help 41

Part II Confi guration 4 Administration Tasks 69

5 Network Connections 91

6 Software Installation 105

7 Software Management with DEB, APT, and dkpg 123

Part III Desktops 8 GNOME 141

9 KDE, KDE 4, and Xfce 177

Part IV Using the Shell 10 The Shell 203

11 Shell Configuration 237

12 Files, Directories, and Archives 255

Part V Applications 13 Offi ce and Database Applications 283

14 Graphics Tools and Multimedia 301

15 Mail and News Clients 321

16 Web Browsers, FTP, Java, VoIP, and IM 337

Part VI Security 17 Authorization, Encryption, and Permissions 359

18 AppArmor and Security-Enhanced Linux 397

19 Secure Shell and Kerberos 413

20 Firewalls 427

v

vi U b u n t u : T h e C o m p l e t e R e f e r e n c e

Part VII System Administration

21 Basic System Administration 449

22 Managing Users 483

23 File Systems 505

24 RAID and LVM 537

25 Devices and Modules 561

26 Backup Management 589

27 Administering TCP/IP Networks 603

Part VIII Local Services 28 Managing Services 633

29 Print, News, and Database Services 655

30 Shared Resources: Samba and NFS 677

A Obtaining the Distribution 703

Index 705

Acknowledgments xxv

Introduction xxvii

Part I Getting Started 1 Introduction to Ubuntu 3

Ubuntu Releases 4

Linux 4

Open Source Software 5

Ubuntu Editions 6

Ubuntu 8.04 LTR 9

Ubuntu LiveCD 10

Ubuntu Software 11

Ubuntu Help and Documentation 12

help.ubuntu.com 13

ubuntuforums.org 13

ubuntuguide.org 14

Ubuntu News and Blog Sites 14

Linux Documentation 14

History of Linux and Unix 14

Unix 14

Linux 15

2 Installing Ubuntu 17

Install CD and DVDs 17

Installation Choices 17

Installing Dual-Boot Systems 18

Hardware, Software, and Information Requirements 19

Hardware Requirements 19

Hard Drive Confi guration 19

Hardware and Device Information 20

Installing Ubuntu 20

Installation Overview 20

Starting the Installation Program 21

Installation 23

Startup Issues 31

Selecting and Editing GRUB 31

Login and Logout 33

Initial Confi guration Tasks 34

vii

For more information about this title, click here

viii U b u n t u : T h e C o m p l e t e R e f e r e n c e

Recovery 34

Reinstalling the Boot Loader 34

Alternate Install 35

Server Install 36

Automating Installation with Kickstart 37

Wubi: Windows-Based Installer 38

3 Interface Basics: Login, Desktop, and Help 41

Accessing Your Linux System 41

The GNOME Display Manager: GDM 42

The User Switcher 43

Accessing Linux from the Command Line Interface 44

The Ubuntu Desktop 44

GNOME Desktop 45

GNOME Applets 48

Desktop Operations 48

International Clock: Time, Date, and Weather 49

Confi guring Personal Information 51

Desktop Background 52

Using Removable Devices and Media 53

Accessing File Systems, Devices, and Remote Hosts 53

Burning DVDs and CDs 53

Search Tools 55

Tracker: Indexed Search 55

Search for Files 57

GNOME File Manager Search 57

GNOME Power Management 58

Using the Command Line Interface 59

Help Resources 60

Ubuntu Help Center 60

Context-Sensitive Help 61

Application Documentation 63

Man Pages 63

Info Pages 63

Running Windows Software on Linux: Wine 64

Part II Confi guration 4 Administration Tasks 69

Ubuntu Administrative Tools 69

Controlled Administrative Access: PolicyKit, sudo, and gksu 71

PolicyKit 71

gksu 72

sudo 73

Login Window Confi guration 73

C o n t e n t s ix

Display Drivers 75

Manual Display Confi guration 77

Confi guring Users 79

Printer Management and Confi guration 79

Sound Confi guration 80

Multimedia Support: MP3, DVD-Video, DivX, and HDTV 80

File System Access 81

Access Linux File Systems on Internal Drives 81

Access for Local Windows NTFS File Systems 82

Access to Local Network Windows NTFS File Systems 82

Shared Folders for Your Network and Windows: NFS and Samba 82

Bluetooth 83

Bluetooth Confi guration 84

System Monitoring 85

Virus Protection 86

Accessing Devices Remotely 87

Managing Services 88

Testing Hardware: Launchpad 89

5 Network Connections 91

NetworkManager 91

NetworkManager on GNOME 92

NetworkManager for KDE: KNetworkManager 93

Wireless Manual Confi guration and Editing 93

Manual Network Confi guration with network-admin 94

Connections 94

General 95

DNS 95

Hosts 96

Command Line PPP Access: WvDial 96

Manual Wireless Confi guration with iwconfi g 97

Accessing Remote Desktops 99

Virtual Network Computing 99

Windows Terminal Servers 101

6 Software Installation 105

Installing Software Packages 105

Ubuntu Package Management Software 106

Updating Ubuntu with Update Manager 107

Managing Packages with Add/Remove Applications 109

Synaptic Package Manager 110

Properties 112

Installing Packages 113

Removing Packages 114

Search Filters 114

Synaptic Confi guration 116

x U b u n t u : T h e C o m p l e t e R e f e r e n c e

Ubuntu Software Repositories 117

Repository Components 117

Repositories 117

Software Sources 118

Ubuntu Repository Confi guration File: sources.list 120

7 Software Management with DEB, APT, and dkpg 123

Software Package Types 123

DEB Software Packages 124

Managing Software with APT 125

Upgrading with apt-get 126

Source Code Files 127

Managing Non-repository Packages with dpkg 127

Using Packages with Other Software Formats 128

Command Line Search and Information: dpkg-query and atp-cache Tools 128

Installing Software from Compressed Archives: tar.gz 130

Decompressing and Extracting Software in One Step 130

Decompressing Software Separately 130

Selecting an Install Directory 131

Extracting Software 131

Compiling Software 132

Confi gure Command Options 133

Development Libraries 134

Shared and StaticLibraries 134

Makefi le File 135

Checking Software Package Digital Signatures 135

Importing Software Public Keys with apt-key 135

Checking Software Compressed Archives 136

Part III Desktops 8 GNOME 141

GNOME 2.22 Features 141

GNOME Desktop Features 142

GNOME Applications 142

GNOME Administration Features 143

GNOME File Manager Features 144

GTK+ 144

The GNOME Interface 145

GNOME Components 146

Quitting GNOME 146

GNOME Help 147

The GNOME Desktop 147

Drag-and-Drop Files to the Desktop 147

C o n t e n t s xi

Applications on the Desktop 148

GNOME Desktop Menu 148

Window Manager 149

GNOME Desktop Preferences 150

The GNOME File Manager: Nautilus 156

Home Folder Subdirectories 156

Nautilus Window 157

Nautilus Side Pane: Tree, History, and Notes 158

Displaying Files and Folders 159

Nautilus Pop-up Menu 159

Navigating Directories 160

Managing Files 161

Application Launcher 162

Preferred Applications for Web, Mail, Accessibility, and Terminal Windows 163

Default Applications for Media 164

File and Directory Properties 165

Nautilus Preferences 166

Nautilus as an FTP Browser 167

Removable Drives and Network Folders 167

The GNOME Panel 169

Panel Properties 170

Panel Objects 171

GNOME Applets 174

Workspace Switcher 174

GNOME Window List 174

GNOME Directories and Files 175

GNOME User Directories 176

The GConf Confi guration Editor 176

9 KDE, KDE 4, and Xfce 177

KDE 177

The KDE Desktop 179

KDE Desktop Operations 181

Confi guration and Administration Access with KDE 182

Confi guring Your Desktop 183

KDE Windows 183

Virtual Desktops: The KDE Desktop Pager 184

KDE Panel: Kicker 185

The KDE Help Center 185

Applications 186

Mounting Devices from the Desktop 187

KDE File Managers: Konqueror and Dolphin 188

Basic File Manager Operations 188

Copy, Move, Delete, Rename, and Link Operations 189

xii U b u n t u : T h e C o m p l e t e R e f e r e n c e

Dolphin File Manager: Kubuntu 3 and 4 190

Konqueror File Manager 191

KDE Confi guration: System Settings 193

.kde and Desktop User Directories 194

KDE Directories and Files 195

KDE 4 196

KDE 4 Desktop and File Manager 197

Xfce4 Desktop 199

Part IV Using the Shell 10 The Shell 203

Accessing Shells 203

The Command Line 204

Command Line Editing 205

Command and Filename Completion 207

History 209

History Events 209

History Event Editing 211

Confi guring History: HISTFILE and HISTSIZE 212

Filename Expansion: *, ?, [ ] 212

Matching Multiple Characters 212

Matching Single Characters 214

Matching a Range of Characters 214

Matching Shell Symbols 215

Generating Patterns 216

Standard Input/Output and Redirection 216

Redirecting the Standard Output: > and >> 217

The Standard Input 219

Pipes | 219

Redirecting and Piping the Standard Error: >&, 2> 220

Jobs: Background, Kills, and Interruptions 221

Running Jobs in the Background 221

Referencing Jobs 222

Job Notifi cation 223

Bringing Jobs to the Foreground 223

Canceling Jobs 223

Suspending and Stopping Jobs 224

Ending Processes: ps and kill 224

Shell Variables 225

Defi nition and Evaluation of Variables: =, $, set, unset 225

Values from Linux Commands: Back Quotes 226

Shell Scripts: User-Defi ned Commands 227

Executing Scripts 228

C o n t e n t s xiii

Script Arguments 228

Control Structures 229

Test Operations 229

Conditional Control Structures 231

Loop Control Structures 233

Filters and Regular Expressions 233

Searching Files: grep 234

Regular Expressions 235

11 Shell Configuration 237

Shell Initialization and Confi guration Files 238

Confi guration Directories and Files 239

Aliases 239

Aliasing Commands and Options 240

Aliasing Commands and Arguments 240

Aliasing Commands 241

Controlling Shell Operations 241

Environment Variables and Subshells: export 242

Confi guring Your Shell with Shell Parameters 242

Shell Parameter Variables 243

Confi guring Your Login Shell: profi le 249

Confi guring the BASH Shell: bashrc 252

The BASH Shell Logout File: bash_logout 254

12 Files, Directories, and Archives 255

Linux Files 255

The File Structure 257

Home Directories 258

Pathnames 258

System Directories 259

Listing, Displaying, and Printing Files: ls, cat, more, less, and lpr 260

Displaying Files: cat, less, and more 260

Printing Files: lpr, lpq, and lprm 261

Managing Directories: mkdir, rmdir, ls, cd, and pwd 261

Creating and Deleting Directories 262

Displaying Directory Contents 263

Moving Through Directories 263

Referencing the Parent Directory 263

File and Directory Operations: fi nd, cp, mv, rm, and ln 264

Searching Directories: fi nd 264

Copying Files 267

Moving Files 268

Copying and Moving Directories 269

Erasing Files and Directories: The rm Command 269

Links: The ln Command 270

xiv U b u n t u : T h e C o m p l e t e R e f e r e n c e

Archiving and Compressing Files 272

Archiving and Compressing Files with File Roller 272

Archive Files and Devices: tar 273

File Compression: gzip, bzip2, and zip 277

Part V Applications 13 Offi ce and Database Applications 283

Running Microsoft Offi ce on Linux: CrossOver and Wine 284

OpenOffi ce.org 286

KOffi ce 287

KOffi ce Applications 287

KParts 288

GNOME Offi ce 289

Document Viewers (PostScript, PDF, and DVI) 290

PDA Access 291

Editors 291

GNOME Editor: Gedit 292

KDE Editors: Kate and KEdit 292

The Emacs Editor 293

The Vi Editor: Vim and Gvim 294

Database Management Systems 297

OpenOffi ce.org Base 298

SQL Databases (RDMS) 298

XBase Databases 300

14 Graphics Tools and Multimedia 301

Graphics Tools 301

Photo Management Tools: F-Spot and digiKam 302

GNOME Graphics Tools 303

KDE Graphics Tools 304

X Window System Graphic Programs 305

Multimedia Tools 306

Ubuntu Codec Wizard 307

GStreamer 307

Sound Drivers and Interfaces 309

Connection Confi guration: GNOME Volume Control 310

PulseAudio and Sound Interfaces 312

Music Applications 314

CD/DVD Burners and Rippers 315

Video Applications 316

15 Mail and News Clients 321

Mail Clients 321

MIME 322

Evolution 323

C o n t e n t s xv

Thunderbird 325

The K Desktop Mail Client: KMail 326

SquirrelMail Webmail Client 327

Command Line Mail Clients 327

Notifi cations of Received Mail 329

Accessing Mail on Remote POP Mail Servers 330

Mailing Lists 331

Usenet News 332

Newsreaders 333

16 Web Browsers, FTP, Java, VoIP, and IM 337

Web Protocols 337

Web Browsers 339

Firefox: The Mozilla Framework 340

The K Desktop File Manager: Konqueror 345

GNOME Web Browsers: Epiphany, Galeon, and Kazehakase 345

Lynx and ELinks: Line-Mode Browsers 345

Java for Linux 345

FTP Clients 346

Network File Transfer: FTP 347

Web Browser–Based FTP: Firefox 347

The KDE File Managers: Konqueror and Dolphin 348

GNOME Desktop FTP: Nautilus 348

gFTP 348

wget 349

curl 349

ftp 349

Automatic Login and Macros: netrc 353

lftp 353

Network Talk and Messenger Clients: VoIP, IRC, and IM 354

Ekiga 354

Instant Messenger: Pidgin 355

Part VI Security 17 Authorization, Encryption, and Permissions 359

Controlled Access with PolicyKit: Authorizations 359

PolicyKit Agent 360

PolicyKit Confi guration Files and Tools 364

Public Key Encryption, Digital Signatures, and Integrity Checks 364

Public Key Encryption 365

Digital Signatures 365

Integrity Checks 365

Combining Encryption and Signatures 366

xvi U b u n t u : T h e C o m p l e t e R e f e r e n c e

Managing Keys with Seahorse 366

Passwords and Encryption Keys: Seahorse 367

Seahorse Settings 370

Making Your Public Keys Available with Seahorse 371

GNU Privacy Guard: gpg 372

Generating Your Public Key with gpg 374

Importing Public Keys 375

Signing Your Public Keys 376

Publishing Keys 377

Using GPG 378

Encrypting and Decrypting Data with the gpg Command 378

Seahorse Plug-ins: Choose Recipients 379

Signing Messages 381

Permissions: Discretionary Access Control 381

Read, Write, and Execute 382

Permissions on GNOME and KDE 382

chmod 384

Ownership 384

Changing a File’s Owner or Group: chown and chgrp 386

Setting Permissions: Permission Symbols 386

Absolute Permissions: Binary Masks 387

Directory Permissions 389

Ownership Permissions 389

Sticky Bit Permissions 390

Permission Defaults: umask 391

Access Control Lists: FACL 392

Encrypted File Systems 394

Intrusion Detection: Tripwire and AIDE 395

18 AppArmor and Security-Enhanced Linux 397

AppArmor 397

AppArmor Utilities 398

AppArmor Confi guration 399

Security Enhanced Linux 400

Flask Architecture 401

System Administration Access 402

Terminology 402

Management Operations for SELinux 404

SELinux Management Tools 405

The SELinux Reference Policy 407

SELinux Confi guration 408

SELinux Policy Rules 408

SELinux Policy Confi guration Files and Modules 410

SELinux: Administrative Operations 410

C o n t e n t s xvii

19 Secure Shell and Kerberos 413

The Secure Shell: OpenSSH 413

SSH Encryption and Authentication 414

SSH Packages, Tools, and Server 416

SSH Setup 417

SSH Clients 420

Port Forwarding (Tunneling) 422

SSH Confi guration 422

Kerberos 423

Kerberos Servers 424

Authentication Process 424

Kerberized Services 426

Kerberos Servers and Clients 426

20 Firewalls 427

Uncomplicated Firewall 427

Firestarter 430

iptables, NAT, Mangle, and ip6tables 433

iptables 433

ip6tables 433

Modules 434

Packet Filtering 434

Chains 434

Targets 435

Firewall and NAT Chains 435

Adding and Changing Rules 436

iptables Options 438

Accepting and Denying Packets: DROP and ACCEPT 438

User-Defi ned Chains 439

ICMP Packets 439

Controlling Port Access 440

Packet States: Connection Tracking 441

Specialized Connection Tracking: ftp, irc, Amanda, tftp 443

Network Address Translation 443

Adding NAT Rules 443

NAT Targets and Chains 444

NAT Redirection: Transparent Proxies 445

Packet Mangling: The Mangle Table 445

IP Masquerading 446

Part VII System Administration 21 Basic System Administration 449

Ubuntu Administrative Tools 449

xviii U b u n t u : T h e C o m p l e t e R e f e r e n c e

Administrative Access 451

Controlled Administrative Access with PolicyKit 451

Controlled Administrative Access with gksu and sudo 452

Full Administrative Access with root, su, and superuser 455

Editing User Confi guration Files Directly 456

Administrative Access from the File Browser 457

System Time and Date 458

Using the time-admin Date and Time Utility 458

Using the date Command 459

Scheduling Tasks with cron 459

crontab Entries 460

Environment Variables for cron 460

The cron.d Directory 461

The crontab Command 461

Editing in cron 461

Organizing Scheduled Tasks 462

Running cron Directory Scripts 463

cron Directory Names 463

Anacron 463

System Directories 464

Program Directories 465

Confi guration Directories and Files 465

System Logs: /var/log and syslogd 465

syslogd and syslog.conf 465

Entries in syslogd.conf 467

Priorities 468

Actions and Users 468

Performance Analysis Tools and Processes 469

GNOME System Monitor 469

The ps Command 471

vmstat, top, free, Xload, iostat, and sar 471

SystemTap 471

GNOME Power Manager 471

GKrellM 472

KDE Task Manager and Performance Monitor (KSysguard) 472

Grand Unifi ed Bootloader 472

Virtualization 476

Virtual Machine Manager: virt-manager 477

KVM Hardware Virtualization 478

Xen Virtualization Kernel 479

22 Managing Users 483

GUI User Management Tools: users-admin 483

Create a New User 483

Manage Groups 485

C o n t e n t s xix

User Confi guration Files 485

The Password Files 486

/etc/passwd 486

/etc/shadow and /etc/gshadow 487

Password Tools 487

Managing User Environments 488

Profi le Scripts 488

/etc/login.defs 488

Controlling User Passwords 488

Adding and Removing Users and Groups with useradd, usermod, and userdel 490

useradd 490

usermod 492

userdel 492

Managing Groups 492

/etc/group and /etc/gshadow 492

User Private Groups 493

Group Directories 493

Managing Groups Using groupadd, groupmod, and groupdel 493

Disk Quotas 494

Quota Tools 494

edquota 495

repquota and quota 496

Lightweight Directory Access Protocol 496

LDAP Confi guration Files 497

Confi guring the LDAP Server: /etc/ldap/slapd.conf 498

LDAP Directory Database: ldif 499

LDAP Tools 501

Pluggable Authentication Modules 501

PAM Confi guration Files 502

PAM Modules 502

23 File Systems 505

File Systems and Directory Trees 506

File System Hierarchy Standard 506

Root Directory: / 506

System Directories 508

The /usr Directory 509

The /media Directory 509

The /mnt Directory 510

The /home Directory 510

The /var Directory 510

The /proc File System 510

The sysfs File System: /sys 510

Device Files: /dev, udev, and HAL 511

xx U b u n t u : T h e C o m p l e t e R e f e r e n c e

Mounting File Systems 515

File System Information 515

Journaling 518

ext3 Journaling 518

ext4 File Systems 519

ReiserFS 519

Mounting File Systems Automatically: /etc/fstab 519

HAL and fstab 520

fstab Fields 520

Auto Mounts 520

mount Options 522

Boot and Disk Check 522

fstab Sample 522

Partition Labels: e2label 524

Windows Partitions 524

noauto 525

Mounting File Systems Manually: mount and umount 525

The mount Command 525

The umount Command 526

Managing CDs/DVDs, USB Drives, and Floppy Disks 527

Mounting Hard Drive Partitions: Linux and Windows 528

Mounting DVD/CD Disc Images 528

Creating File Systems: mkfs, mke2fs, mkswap, parted, and fdisk 528

Parted and GParted 530

Fdisk 532

mkfs 533

mkswap 534

CD/DVD Disc Recording 534

Mono and NET Support 535

24 RAID and LVM 537

Logical Volume Manager 538

LVM Structure 538

Creating LVMs During Installation 539

system-confi g-lvm 539

Using the LVM Commands 542

LVM Example for Multiple Hard Drives 546

Using LVM to Replace Drives 547

LVM Snapshots 548

Confi guring RAID Devices 549

Motherboard RAID Support: dmraid 549

Linux Software RAID Levels 550

RAID Devices and Partitions: md and fd 552

Booting from a RAID Device 552

RAID Administration: mdadm 553

Creating and Installing RAID Devices 553

C o n t e n t s xxi

25 Devices and Modules 561

The sysfs File System: /sys 561The proc File System: /proc 562udev: Device Files 563udev Confi guration 564Device Names and udev Rules: /etc/udev/rules.d 564Symbolic Links 567Persistent Rules 568Generated Rules 569Creating udev Rules 569SYMLINK Rules 570Manually Creating Persistent Names: udevinfo 570Permission Fields: MODE, GROUP, OWNER 571Hardware Abstraction Layer 572The HAL Daemon and hal-device-manager (hal-gnome) 573HAL Confi guration: /etc/hal/fdi and /usr/share/hal/fdi 573Device Information Files: fdi 573Properties 574Device Information File Directives 575Manual Devices 577Installing and Managing Terminals and Modems 579Serial Ports 579mingetty, mgetty, and getty 579Input Devices 579Installing Other Cards 580Sound Devices 580Video and TV Devices 581PCMCIA Devices 581Modules 582Kernel Module Tools 582Module Files and Directories: /lib/modules 582Managing Modules with modprobe and /etc/modules 583The depmod Command 583The modprobe Command 584The insmod Command 584The rmmod Command 585modprobe Confi guration 585Installing New Modules from Vendors: Driver Packages 585

26 Backup Management 589

Individual Backups: archive and rsync 589BackupPC 591BackupPC Server Confi guration 592BackupPC Host Backup and Confi guration 593

xxii U b u n t u : T h e C o m p l e t e R e f e r e n c e

Amanda 595Amanda Commands 595Amanda Confi guration 595Enabling Amanda on the Network 597Using Amanda 597Backups with Dump and Restore 598The dump Levels 598Recording Backups 600Operations with dump 600Recovering Backups 601

27 Administering TCP/IP Networks 603

TCP/IP Protocol Suite 603Zero Confi guration Networking: Avahi and Link Local Addressing 606IPv4 and IPv6 606TCP/IP Network Addresses 607IPv4 Network Addresses 607Class-Based IP Addressing 608Netmask 608Classless Interdomain Routing 609Obtaining an IP Address 610Broadcast Addresses 611Gateway Addresses 611Name Server Addresses 611IPv6 Addressing 612IPv6 Address Format 612IPv6 Interface Identifi ers 613IPv6 Address Types 613TCP/IP Confi guration Files 614Identifying Hostnames: /etc/hosts 615/etc/resolv.conf 616/etc/services 616/etc/protocols 616/etc/network 616/etc/network/interfaces 617Network Autoconfi guration with IPv6, DHCPv6, and DHCP 617IPv6 Stateless Autoconfi guration 618IPv6 Stateful Autoconfi guration: DHCPv6 619Linux as an IPv6 Router: radvd 621DHCP for IPv4 622Domain Name Service 624host.conf 625Network Interfaces and Routes: ifconfi g and route 625Monitoring Your Network: EtherApe, Ping, Ettercap,

Wireshark, Tcpdump, and Netstat 626Ping 626

C o n t e n t s xxiii

Ettercap 626Wireshark 627Tcpdump 628Netstat 629

Part VIII Local Services

28 Managing Services 633

Upstart 633Upstart and Runlevels: event.d and init.d 636Runlevels 636Runlevels in event.d directory 637Using telinit 637Default Runlevel 638Command Line Runlevel 638The runlevel Command 638System Startup Files and Scripts 639rc.local 639/etc/init.d 639/etc/init.d/rc 640/etc/event.d 640Service Scripts: /etc/init.d 640Managing Services 642Managing Services Directly 642Service Management: services-admin, rrconf, sysv-rc-conf,

and update-rc.d 643services-admin 644rcconf and sysv-rc-conf 644update-rc.d 645Extended Internet Services Daemon (xinetd) 647xinetd and inetd Servers 647xinetd Confi guration: xinetd.conf 647xinetd Service Confi guration Files: /etc/xinetd.d Directory 648Confi guring Services: xinetd Attributes 649Disabling and Enabling xinetd Services 649TCP Wrappers 652

29 Print, News, and Database Services 655

Printer Services: CUPS 655Printer Devices and Confi guration 656Printer Device Files 656Spool Directories 657Installing Printers 657Confi guring Printers on Ubuntu with system-confi g-printer 657Confi guring Printers with KDE 661

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CUPS Web Browser–based Confi guration Tool 661Confi guring Remote Printers on CUPS 663CUPS Printer Classes 666CUPS Confi guration Files 666cupsd.conf 666CUPS Directives 666CUPS Command Line Print Clients 667lpr 668lpc 668lpq and lpstat 668lprm 668CUPS Command Line Administrative Tools 669lpadmin 669lpoptions 670enable and disable 670accept and reject 670News Servers 671Database Servers: MySQL and PostgreSQL 671Relational Database Structure 672MySQL 673PostgreSQL 675

30 Shared Resources: Samba and NFS 677

Samba 677Samba Applications 678Starting Samba 680Firewall Access 680Setting Up Samba with Confi guration Tools 681Confi guring Samba Access from Windows 684User-Level Security 685The Samba smb.conf Confi guration File 688Testing the Samba Confi guration 694Accessing Samba Services with Clients 694Network File Systems: NFS and /etc/exports 697Setting Up NFS Directories with shared-admin: Shared Folders 698NFS Confi guration: /etc/exports 698NFSv4 701Mounting NFS File Systems: NFS Clients 701Distributed Network File Systems 702

A Obtaining the Distribution 703 Index 705

I would like to thank all those at McGraw-Hill who made this book a reality, particularly

Jane Brownlow, acquisitions editor, for her continued encouragement and analysis as well as management of such a complex project; Ibrahim Haddad, the technical editor, whose analysis and suggestions proved very insightful and helpful; Jennifer Housh,

editorial assistant, who provided needed resources and helpful advice; Lisa Theobald, copy editor, for her excellent job editing as well as insightful comments; project manager Arushi Chawla incorporated the large number of features found in this book and coordinated the intricate task of generating the final version

Special thanks to Linus Torvalds, the creator of Linux, and to those who continue to develop Linux as an open, professional, and effective operating system accessible to anyone Thanks also to the academic community whose special dedication has developed Unix as a flexible and versatile operating system I would also like to thank professors and students at the University of California, Berkeley, for the experience and support in developing new and different ways of understanding operating system technologies

I would also like to thank my parents, George and Cecelia, and my brothers, George, Robert, and Mark, for their support and encouragement with such a difficult project Also Marylou and Valerie and my nieces and nephews, Aleina, Larisa, Justin, Christopher, and Dylan, for their support and deadline reminders

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Ubuntu has become one of the major Linux distributions, designed to make Linux an

operating system for end users This book is designed not only to be a complete reference on Ubuntu, but also to provide clear and detailed explanations of its features

No prior knowledge of Unix is assumed; Linux is an operating system anyone can use.The Ubuntu distribution is designed to be an operating system for people In the past, most Linux distributions were designed for enterprise-critical server operations, where Linux dominates Often, difficult administration procedures where required for the simplest tasks

By contrast, Ubuntu supports primarily end users Ubuntu is Linux for people, ordinary users who just want a powerful and easy-to-use operating system at their fingertips Linux

in general has dramatically increased its ability to handle most tasks automatically Printers, cameras, USB sticks, and Windows disks are all detected and managed for you Your graphics card is also detected and configured for you, making full use of the recent greatly improved support for Linux by ATI and Nvidia Ubuntu pulls all these developments together for the end user, making Linux a user experience that is a simple, effective, reliable, and powerful connection to the information society

Ubuntu Long-term and Short-term Releases

Ubuntu has split its Linux development into two lines: the long-term and short-term releases The long-term release aims to provide a stable release for end users, whereas short-term releases take advantage of the latest software and device support Users who are comfortable with modifying and tweaking their systems often install the short-term releases, whereas those who want only a reliable and stable system install the long-term releases

Ubuntu Editions

The entire collection of Ubuntu software is available on the Ubuntu repository Some users, however, might prefer to start with preselected setup applications on an install CD/DVD

These are known as editions, but each edition has full access to all Ubuntu software The

Ubuntu Web site lists several editions, including Kubuntu (KDE desktop), Edubuntu (educational packages), and Xubuntu (Xfce4 desktop) Other commonly used editions are Ubuntu Studio (audio, video, and graphic applications) and Mythbuntu (multimedia and MythTV)

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Important Features with Ubuntu 8.04, Hardy Heron

With Ubuntu 8.04, several key features are incorporated as standardized and stable components of the Linux operations system These include changes to distribution methods, device detection, security support, and desktop use Some of these are listed here, with a complete listing in Chapter 1

• Ubuntu features automatic detection and configuration of removable devices such

as USB printers, digital cameras, and card readers, treating CD/DVD discs as removable devices, as well as fully detecting IDE CD/DVD devices

• Ubuntu software, both supported and third-party, is easily downloaded and updated from the Ubuntu software repositories

• Ubuntu is available in several editions, designed for users with particular preferences

• Audio is managed by the PulseAudio sound interface

• PolicyKit provides controlled access to system administration tools and shared resources You can set different levels of control and create your own policies

• Extensive and simple virtualization support provided using Xen, KVM, and the Virtual Machine Manager

• GNOME 2.2 with new desktop applications such as the Brasero DVD/CD burner and the World Clock applet

Linux Features

Ubuntu includes features that have become a standard part of any Linux distribution, such

as the desktops, Unix compatibility, network servers, and numerous software applications such as office, multimedia, and Internet applications GNOME and the K Desktop

Environment (KDE) have become standard desktop graphical user interfaces (GUIs) for Linux, noted for their power, flexibility, and ease of use KDE and GNOME have become the standard GUIs for Linux systems You can install both, run applications from one on the other, and easily switch from one to the other Both have become integrated components of Linux, with applications and tools for every kind of task and operation Instead of treating GNOME and KDE as separate entities, GNOME and KDE tools and applications are presented equally throughout the book

A wide array of applications operates on Ubuntu Numerous applications are continually released on the Ubuntu repositories The GNU general public licensed software provides professional-level applications such as programming development tools, editors, and word processors, as well as numerous specialized applications such as those for graphics and sound

How to Use This Book

The first two sections of the book are designed to cover tasks you would need to perform to get your system up and running After an introduction to the working environment, including both GNOME and KDE desktops, you learn some basic configuration tasks, such as setting preferences for your desktop and enabling network connections Most administrative tasks are now handled for you automatically, detecting devices such as printers and USB drives, as well as providing access Some tasks, such as adding new users, you will have to perform yourself The software management is nearly automatic, letting you install software on your

On the other hand, if you want to delve deeper into the Unix aspects of Linux, you can check out the shell chapters and the corresponding shell-based commands in other chapters Single users may concentrate more on the desktops and the Internet features, whereas administrators may make more use of the security and networking features.

Section Topics

The first part of this book is designed to help you start using Ubuntu quickly It provides an introduction to Ubuntu and its current features Streamlined installation procedures that take about 30 minutes or less are covered in detail The installation program provides excellent commentary, describing each step in detail You then learn the essentials of using the desktop and setting your preferences such as font sizes and backgrounds

Part II deals with system configuration, network connections, and software management Commonly performed system configuration tasks such as adding printers and setting up virus protection are presented with the easiest methods, without much of the complex detail described in the administration chapters that is unnecessary for basic operations Basic network connection tasks are discussed, such as setting up a LAN and wireless connections

You learn how to update and install new software easily using Ubuntu repositories You can install the latest versions directly from a repository with a few clicks The software updater automatically detects updates and lets you perform all updates with a single click

Part III of this book deals with the Ubuntu desktops Here you are introduced to the two GUIs commonly used on Linux: KDE and GNOME Different features such as applets, the Control Panel, and configuration tools are described in detail At any time, you can open up

a terminal window in which you can enter standard Linux commands on a command line

Part IV covers shell commands and configuration as well as files and directory management from the shell You can choose to use just the standard Unix command line interface to run any of the standard Unix commands The BASH shell and its various file and directory commands are examined, along with shell configuration files

Part V of this book discusses in detail the many office, multimedia, and Internet applications you can use on your Linux system, beginning with office suites such as OpenOffice and KOffice A variety of different text editors are available, including several GNOME and KDE editors, as well as the Vim (enhanced VI) Linux automatically installs mail, news, FTP, and Web browser applications Both KDE and GNOME come with a full set of mail, news, FTP clients, and Web browsers

Part VI demonstrates how to implement security precautions using encryption, authentication, and firewalls Coverage of the GNU Privacy Guard (GPG) tells you how to implement public and private key based encryption, as well as how to configure PolicyKit to control access to administrative tools AppArmor and SELinux provide comprehensive and refined control of all your network and system resources Network security topics cover

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firewalls and encryption using netfilter (iptables) to protect your system, the Secure Shell (SSH) to provide secure remote transmissions, and Kerberos to provide secure authentication.Part VII discusses system and network administration topics including user, file system, system, device, and kernel administration Detailed descriptions cover the configuration files used in administration tasks and how to make entries in them Presentations include both the GUI tools you can use for these tasks and the underlying configurations files and commands First, basic system administration tasks are covered such as managing runlevels, monitoring your system, and scheduling shutdowns Then aspects of setting up and controlling users and groups are discussed Different methods of virtualization are covered, such as full (KVM) and para-virtualizaton (Xen) With the Virtual Machine Manager, both can easily be used to install and run guest operation systems Different file system tasks are covered such as mounting file systems, managing file systems with HAL and udev, and configuring RAID devices and LVM volumes Devices are automatically detected with udev and HAL Backup managements tools are discussed, including BackupPC and Amanda IPv6 support for Internet addressing is discussed in detail, showing the new IPv6 formats replacing the older IPv4 versions You also learn how IPv4 Dynamic Host Configuration Protocol (DHCP) server assigns hosts IP addresses dynamically and how IPv6 automatic addressing and

renumbering operate

Part VIII covers local network services such as the CUPS print server network file systems, and Samba Windows servers The network file system, NFS for Unix, is presented The chapter on Samba shows how to access Windows file systems and printers

The appendix provides information, sites, and details for obtaining Ubuntu disc images and creating your own Ubuntu Live and install CD/DVD discs

Introduction to Ubuntu

CHAPTER 2Installing Ubuntu

CHAPTER 3Interface Basics: Login, Desktop, and Help

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1 Introduction to Ubuntu

Ubuntu is currently one of the most popular end-user Linux distributions (www

.ubuntu.com) It is managed by the Ubuntu Foundation, which is sponsored by

Canonical, Ltd (www.canonical.com), a commercial organization that supports and

promotes open source projects The Ubuntu Project was initiated by Mark Shuttleworth, a Debian Linux developer in South Africa Ubuntu is based on Debian Linux, one of the oldest Linux distributions, which is dedicated to incorporating cutting-edge developments

and features (www.debian.org) Debian Linux is an open source operating system that

relies on the collaboration of volunteers from around the world

Ubuntu provides a Debian-based Linux distribution that is stable, reliable, and easy to use It is designed as a Linux operating system that can be used easily by everyone The

name Ubuntu means “humanity to others.” As the Ubuntu Project describes it, “Ubuntu is

an African word meaning ‘Humanity to others,’ or ‘I am what I am because of who we all are.’ The Ubuntu distribution brings the spirit of Ubuntu to the software world.”

The official Ubuntu philosophy lists the following principles:

• Every computer user should have the freedom to download, run, copy, distribute, study, share, change, and improve his or her software for any purpose, without paying licensing fees

• Every computer user should be able to use software in the language of his or her choice

• Every computer user should be given every opportunity to use software, including users who are affected by any type of disability

The emphasis on language reflects Ubuntu’s international scope It is meant to be a global distribution that does not focus on any single market Language support has been integrated into Linux in general by its internationalization projects, denoted by the term

i18n You can find information about i18n at sites such as www.li18nux.net (The Linux

Foundation) and www.openi18n.orgs.

Making software available to all users involves both full accessibility support for users with disabilities as well as seamless integration of software access using online repositories, making massive amounts of software available to all users at the touch of a button Ubuntu also makes full use of recent developments in automatic device detection, greatly simplifying installation as well as access to removable devices and attached storage

3

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4 P a r t I : G e t t i n g S t a r t e d

Ubuntu aims to provide a fully supported and reliable, open source and free, easy to use and modify, Linux operating system Ubuntu makes the following promises about its distribution:

• Ubuntu will always be free of charge, including enterprise releases and security updates

• Ubuntu comes with full commercial support from Canonical and hundreds of companies around the world

• Ubuntu includes the very best translations and accessibility infrastructure that the free software community has to offer

• Ubuntu CDs contain only free software applications; you are encouraged to use free and open source software, improve it, and pass it on

Ubuntu Releases

Ubuntu provides both long-term and short-term releases Long-term support (LTS) releases, such as Ubuntu 8.04, are released every two years Short-term releases are provided every six months between the LTS version They are designed to make available the latest

application and support for the newest hardware Each has its own nickname, such as Hardy Heron for the 8.04 LTS release The long-term releases are supported for three years for

desktops and five years for servers, whereas short-term releases are supported for 18 months Canonical also provides limited commercial support for companies that purchase it

Installing Ubuntu has been significantly simplified A core set of applications are installed, and you can add to them as you wish Following installation, additional software can be downloaded from online repositories Install screens have been reduced in number and allow users to move quickly through default partitioning, user setup, and time settings The hardware such as graphics cards and network connections are now configured and detected automatically

The Ubuntu distribution of Linux is available online at numerous sites Ubuntu

maintains its own site at www.ubuntu.com/getubuntu, where you can download the

current release of Ubuntu

Linux

Linux is an fast, stable, and open source operating system for PCs and workstations that

features professional-level Internet services, extensive development tools, fully functional graphical user interfaces (GUIs), and a massive number of applications ranging from office suites to multimedia applications Linux was developed in the early 1990s by Linus Torvalds, along with other programmers around the world (see the history section later in the chapter) As an operating system, Linux performs many of the same functions as Unix, Macintosh, Windows, and Windows NT However, Linux is distinguished by its power and flexibility, along with being freely available

Most PC operating systems, such as Windows, began their development within the confines of small, restricted personal computers, which have only recently become more versatile machines Such operating systems are constantly being upgraded to keep up with the ever-changing capabilities of PC hardware Linux, on the other hand, was developed in

Technically, Linux consists of the operating system program, referred to as the kernel,

which is the part originally developed by Torvalds But it has always been distributed with

a large number of software applications, ranging from network servers and security programs to office applications and development tools Linux has evolved as part of the open source software movement, in which independent programmers joined forces to provide free and quality software to any user Linux has become the premier platform for open source software, much of it developed by the Free Software Foundation’s GNU project Many of these applications are bundled as part of standard Linux distributions, and most of them are also incorporated into the Ubuntu repository, using packages that are Debian compliant

Along with Linux’s operating system capabilities come powerful networking features, including support for Internet, intranets, and Windows networking As a norm, Linux distributions include fast, efficient, and stable Internet servers, such as the Web, FTP, and DNS servers, along with proxy, news, and mail servers In other words, Linux has everything you need to set up, support, and maintain a fully functional network

With the both GNOME and K Desktop Environment (KDE), Linux also provides GUIs with the same level of flexibility and power Linux enables you to choose the interface you want and then customize it, adding panels, applets, virtual desktops, and menus, all with full drag-and-drop capabilities and Internet-aware tools

Linux does all this at the right price: It is free, including the network servers and GUI desktops Unlike the official Unix operating system, Linux is distributed freely under a GNU General Public License (GPL) as specified by the Free Software Foundation, making it

available to anyone who wants to use it GNU (which stands for GNU’s Not Unix) is a

project initiated and managed by the Free Software Foundation to provide free software to users, programmers, and developers Linux is copyrighted, not public domain; however, a GNU public license has much the same effect as the software’s being in the public domain

The GNU GPL is designed to ensure that Linux remains free and, at the same time, standardized Linux is technically the operating system kernel—the core operations—and only one official Linux kernel exists People sometimes have the mistaken impression that Linux is somehow less than a professional operating system because it is free Linux is, in fact, a PC, workstation, and server version of Unix Many actually consider it far more stable and much more powerful than Microsoft Windows This power and stability have made Linux an operating system of choice as a network server

Open Source Software

Linux is developed as a cooperative open source effort over the Internet, so no company or institution controls Linux Software developed for Linux reflects this background

Development often takes place when Linux users decide to work together on a project The software is posted at an Internet site, and any Linux user can then access the site and download the software Linux software development has always operated in an Internet

on the Internet Many major software development efforts are also open source projects, as are the KDE and GNOME desktops along with most of their applications The OpenOffice office suite supported by Sun is an open source project based on the StarOffice office suite (Sun’s commercial version of OpenOffice) You can find more information about the Open

Source Initiative at www.opensource.org.

Open source software is protected by public licenses that prevent commercial companies from taking control of the software by adding modifications of their own, copyrighting those changes, and selling the software as their own product The most popular public license is the GNU GPL, under which Linux is distributed, which is provided by the Free Software Foundation The GNU GPL retains the copyright, freely licensing the software with the requirement that the software and any modifications made

to it are always freely available Other public licenses have been created to support the demands of different kinds of open source projects The GNU Lesser General Public License (LGPL) lets commercial applications use GNU-licensed software libraries The Qt Public License (QPL) lets open source developers use the Qt libraries essential to the KDE desktop

You can find a complete listing at www.opensource.org.

Linux is currently copyrighted under a GNU public license provided by the Free

Software Foundation, and it is often referred to as GNU software (see www.gnu.org) GNU

software is distributed free, provided it is freely distributed to others GNU software has proved both reliable and effective Many of the popular Linux utilities, such as C compilers, shells, and editors, are GNU software applications Installed with your Linux distribution are the GNU C++ and Lisp compilers, Vi and Emacs editors, BASH and TCSH shells, as well as TeX and Ghostscript document formatters In addition, many open source software projects are licensed under the GNU GPL Most of these applications are available on the Ubuntu software repositories Chapters 6 and 7 describe in detail the process of

downloading software applications from Internet sites and installing them on your system.Under the terms of the GNU GPL, the original author retains the copyright, although anyone can modify the software and redistribute it, provided the source code is included, made public, and provided free Also, no restriction exists on selling the software or giving

it away free One distributor could charge for the software, while another could provide it free of charge Major software companies are also providing Linux versions of their most popular applications Oracle provides a Linux version of its Oracle database (At present, no plans seem in the works for Microsoft applications, though you can use the Wine, the Windows compatibility layer, to run many Microsoft applications on Linux, directly.)

Ubuntu Editions

Ubuntu is released in several editions, each designed for a distinct group of users or functions (see Table 1-1) Editions install different collections of software such as the KDE, the XFce desktop, servers, educational software, and multimedia applications ISO images can be downloaded directly or using a BitTorrent application

www.ubuntu.com/getubuntu/download.Those who want to run Ubuntu as a server to provide an Internet service such as a Web site would use the Ubuntu Server Edition The Server Edition provides only a simple command line interface; it does not install the desktop It is primarily designed to run servers Keep in mind that you could install the desktop first and later download server software from the Ubuntu repositories, running them from a system that also has a desktop

You do not have to install the Server Edition to install and run servers The Server Edition can be downloaded from the Get Ubuntu Download page

Users who want more enhanced operating system features such as RAID arrays or file system encryption would use the alternate edition The alternate edition, along with the

Desktop and Server editions, can be downloaded directly from http://releases.ubuntu.com/

hardy or http://releases.ubuntu.com/8.04.

Other editions use either a different desktop or a specialized collection of software for

certain groups of users Links to the editions are listed on the www.ubuntu.com Web page

From there you can download their live/install CDs The Kubuntu edition used KDE instead

of GNOME Xubuntu uses the XFce desktop instead of GNOME This is a stripped down and highly efficient desktop, ideal for low power use on laptops and smaller computer The Edubuntu edition provides educational software and can also be used with a specialized Edubuntu server to provide educational software on a school network The Goubuntu edition is a modified version of the standard edition that includes only open source software,

TABLE 1-1 Ubuntu Editions

Ubuntu Edition DescriptionDesktop install LiveCD using GNOME desktop, www.ubuntu.com/getubuntu

Server install Install server software (no desktop), www.ubuntu.com/getubuntu

Alternate install Install enhanced features, www.releases.ubuntu.com

Kubuntu LiveCD using KDE instead of GNOME, www.kubuntu.org

Xubuntu Uses the Xfce desktop instead of GNOME, www.xubuntu.org Useful for