by Naba Barkakati
Red Hat ®
Fedora ™ Linux ® 2
A L L - I N - O N E D E S K R E F E R E N C E FOR
DUMmIES
‰by Naba Barkakati
Red Hat ®
Fedora ™ Linux ® 2
A L L - I N - O N E D E S K R E F E R E N C E FOR
DUMmIES
‰Red Hat®Fedora™Linux® 2 All-in-One Desk Reference For Dummies® Published by
Wiley Publishing, Inc.
111 River Street Hoboken, NJ 07030-5774
Copyright © 2004 by Wiley Publishing, Inc., Indianapolis, Indiana Published by Wiley Publishing, Inc., Indianapolis, Indiana Published simultaneously in Canada
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About the Author
Naba Barkakati is an electrical engineer and a successful computer-book author who has experience in a wide variety of systems, ranging from MS-DOS and Windows to UNIX and Linux. He bought his first personal computer — an IBM PC-AT — in 1984 after graduating with a PhD in electrical engineering from the University of Maryland at College Park. While pursuing a full-time career in engineering, Naba dreamed of writing software for the emerging PC software market. As luck would have it, instead of building a software empire like Microsoft, he ended up writing successful computer books. Currently, Naba is a Senior Level Technologist at the Center for Technology and Engineering in the U.S. General Accounting Office.
Over the past 15 years, Naba has written over 25 computer books on a number of topics ranging from Windows programming with C++ to Linux. He has authored several bestselling titles, such as The Waite Group’s Turbo C++ Bible, Object-Oriented Programming in C++, X Window System Programming, Visual C++ Developer’s Guide, Borland C++ 4 Developer’s Guide, and Linux Secrets. His books have been translated into many languages, including Spanish, French, Polish, Greek, Italian, Chinese, Japanese, and Korean. Naba’s most recent book is Red Hat Linux 9 Professional Secrets, also published by Wiley.
Naba lives in North Potomac, Maryland, with his wife Leha, and their chil- dren, Ivy, Emily, and Ashley.
Dedication
I would like to dedicate this book to my wife Leha, and daughters Ivy, Emily, and Ashley.
Author’s Acknowledgments
I am grateful to Terri Varveris for getting me started on this book — a set of nine quick reference guides on all aspects of Red Hat Linux. As the project editor, Linda Morris guided me through the manuscript-submission process and kept everything moving. I appreciate the guidance and support that Terri and Linda gave me during this project.
I would like to thank Jason Luster for reviewing the manuscript for technical accuracy and providing many useful suggestions for improving the book’s content.
Thanks to everyone at Wiley Publishing for transforming my raw manuscript into this well-edited and beautifully packaged book.
Of course, there would be no reason for this book if it were not for Linux. For this, we have Linus Torvalds and the legions of Linux developers around the world to thank. Thanks to Red Hat for providing beta copies of Red Hat Linux and the publisher’s edition CDs that are bundled with this book.
Finally, and as always, my greatest thanks go to my wife, Leha, and our daughters, Ivy, Emily, and Ashley — it is their love and support that keeps me going. Thanks for being there!
Publisher’s Acknowledgments
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Contents at a Glance
Introduction ...1
Book I: Fedora Basics ...7
Chapter 1: Introducing Fedora Core ...9
Chapter 2: Installing Fedora Core ...31
Chapter 3: Troubleshooting and Configuring Fedora Core ...57
Chapter 4: Trying Out Fedora Core ...75
Chapter 5: Cool Fedora Core Install Projects ...99
Book II: Workstations and Applications ...109
Chapter 1: Exploring the GUI Desktops ...111
Chapter 2: Learning the Shell ...135
Chapter 3: Navigating the Linux File System ...153
Chapter 4: Exploring Fedora Core Applications ...169
Chapter 5: Using Text Editors ...199
Book III: OpenOffice.org ...211
Chapter 1: Writing with OpenOffice.org Writer ...213
Chapter 2: Preparing Spreadsheets with OpenOffice.org Calc ...237
Chapter 3: Making Presentations with OpenOffice.org Impress ...249
Chapter 4: Drawing with OpenOffice.org Draw ...261
Book IV: Networking ...269
Chapter 1: Connecting to the Internet ...271
Chapter 2: Setting Up a Local Area Network ...295
Chapter 3: Adding a Wireless Ethernet LAN ...307
Chapter 4: Managing the Network ...319
Chapter 5: Cool Networking Projects ...329
Book V: Internet ...335
Chapter 1: Exchanging E-Mail and Instant Messages ...337
Chapter 2: Using the Web ...351
Chapter 3: Reading Newsgroups ...371
Chapter 4: Transferring Files with FTP ...383
Book VI: Administration ...391
Chapter 1: Performing Basic System Administration ...393
Chapter 2: Managing Users ...425
Chapter 3: Managing the File System ...437
Chapter 4: Managing Applications ...461
Chapter 5: Managing Devices and Printers ...479
Chapter 6: Upgrading and Customizing the Kernel ...493
Book VII: Security ...519
Chapter 1: Understanding Network and Host Security ...521
Chapter 2: Securing the Host ...535
Chapter 3: Securing the Network ...557
Chapter 4: Performing Security Audits ...577
Book VIII: Internet Servers ...595
Chapter 1: Managing the Servers ...597
Chapter 2: Running the Apache Web Server ...615
Chapter 3: Setting Up the FTP Server ...639
Chapter 4: Serving Up Mail and News ...647
Chapter 5: Setting Up DNS ...675
Chapter 6: Running Samba and NFS ...695
Book IX: Programming ...707
Chapter 1: Fedora Core Programming Essentials ...709
Chapter 2: Programming in C ...735
Chapter 3: Writing Shell Scripts ...767
Chapter 4: Programming in Perl ...779
Appendix: About the DVD ...807
Index ...811
Table of Contents
Introduction ...1
About This Book ...1
Conventions Used in This Book ...2
What You Don’t Have to Read ...2
Who Are You? ...3
How This Book Is Organized ...3
What’s on the DVD? ...4
Icons Used in This Book ...5
Where to Go from Here ...5
Book I: Fedora Basics ...7
Chapter 1: Introducing Fedora Core . . . .9
What Is Fedora Core? ...9
Operating systems and Linux ...9
Linux distributions ...11
Transitioning to the Fedora Project ...11
Making sense of version numbers ...12
Under the hood in Linux kernel 2.6 ...13
What Fedora Core Includes ...16
GNU software ...16
GUIs and applications ...19
Networks ...20
Internet servers ...21
Software development ...22
Online documentation ...23
What Fedora Core Helps You Manage ...25
Disks, CD-ROMs, and DVD-ROMs ...25
Peripheral devices ...26
File systems and sharing ...27
Network ...27
How Do I Get Started? ...28
Install ...28
Configure ...28
Explore ...29
Learn ...29
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Chapter 2: Installing Fedora Core . . . .31
Following the Installation Steps ...31
Checking Your PC’s Hardware ...33
Setting Aside Space for Fedora Core ...34
Defragmenting your hard disk ...34
Resizing your hard disk partition ...36
Starting the Fedora Core Installation ...39
Selecting Keyboard, Mouse, and Installation Type ...40
Partitioning the Disk for Fedora Core ...43
Setting Up Key System Parameters ...47
Installing the boot loader ...47
Configuring the network ...48
Configuring the firewall and SELinux ...50
Selecting languages to support ...51
Setting the time zone ...51
Setting the root password ...52
Selecting and Installing the Package Groups ...53
Chapter 3: Troubleshooting and Configuring Fedora Core . . . .57
Using Text Mode Installation ...58
Using the linux noprobe Command ...58
Troubleshooting X ...59
Resolving Other Installation Problems ...61
The fatal signal 11 error ...61
Using kernel boot commands ...62
Setting Up Printers ...64
Turning On Sound ...68
Adding User Accounts ...69
Managing DVDs and CD-ROMs ...71
Installing RPM Packages ...72
Chapter 4: Trying Out Fedora Core . . . .75
Booting Fedora Core ...75
Exploring GUI Desktops ...81
GNOME ...81
KDE ...88
Playing with the Shell ...94
Starting the Bash shell ...95
Understanding shell commands ...95
Trying a few Linux commands ...96
Shutting Down ...98
Chapter 5: Cool Fedora Core Install Projects . . . .99
Joining the BitTorrent ...99
Things you need ...100
Steps to follow ...100
Table of Contents xi
Burning Fedora Core CDs ...103
Things you need ...103
Steps to follow ...103
Preparing a Fedora Core DVD ...104
Things you need ...104
Steps to follow ...105
Doing an FTP Install ...107
Things you need ...107
Steps to follow ...107
Book II: Workstations and Applications ...109
Chapter 1: Exploring the GUI Desktops . . . .111
Learning the Common Features of the GUIs ...111
Desktop pop-up menus ...112
Icon pop-up menus ...113
The panel ...114
The Main Menu ...116
Exploring GNOME ...119
Using the Nautilus shell ...120
Configuring GNOME ...124
Exploring KDE ...127
Using Konqueror ...128
Configuring KDE ...132
Chapter 2: Learning the Shell . . . .135
Opening Terminal Windows and Virtual Consoles ...135
Using the Bash Shell ...136
Learning the syntax of shell commands ...136
Combining shell commands ...138
Controlling command input and output ...138
Typing less with automatic command completion ...140
Going wild with asterisks and question marks ...140
Repeating previously typed commands ...142
Learning Linux Commands ...142
Becoming root (superuser) ...146
Managing processes ...147
Working with date and time ...147
Processing files ...148
Writing Shell Scripts ...151
Chapter 3: Navigating the Linux File System . . . .153
Understanding the Linux File System ...153
Navigating the File System with Linux Commands ...157
Commands for directory navigation ...158
Commands for directory listings and permissions ...159
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Commands for changing permissions and ownerships ...162
Commands for working with files ...163
Commands for working with directories ...164
Commands for finding files ...165
Commands for mounting and unmounting ...166
Commands for checking disk-space usage ...167
Chapter 4: Exploring Fedora Core Applications . . . .169
Taking Stock of the Fedora Core Applications ...169
Office Applications and Tools ...171
Calculators ...172
Commercially available office applications for Linux ...173
aspell spelling checker ...175
Databases ...176
Adding a database user ...177
Reviewing the steps to build the database ...178
Designing the database ...179
Creating an empty database ...180
Using the PostgreSQL interactive terminal ...180
Defining a table ...181
Inserting records into a table ...182
Querying the database ...182
Multimedia Applications ...183
Using a digital camera ...183
Playing audio CDs ...186
Playing sound files ...187
Burning a CD ...188
Graphics and Imaging ...193
The GIMP ...194
Gnome Ghostview ...196
Chapter 5: Using Text Editors . . . .199
Using GUI Text Editors ...199
Text Editing with ed and vi ...200
Using ed ...201
Using vi ...204
Book III: OpenOffice.org ...211
Chapter 1: Writing with OpenOffice.org Writer . . . .213
Getting Documents from Others ...214
Taking Stock of OpenOffice.org Writer ...215
Table of Contents xiii
Getting Started with Writer ...216
Examining the Writer main window ...217
Setting up Writer ...218
Preparing Documents in Writer ...221
Editing and reviewing documents ...221
Using styles and templates ...224
Performing page layout ...228
Creating and inserting graphics ...231
Using fields ...233
Working with large documents ...235
Chapter 2: Preparing Spreadsheets with OpenOffice.org Calc . . . .237
Taking Stock of OpenOffice.org Calc ...237
Getting Started with Calc ...238
Examining the Calc main window ...239
Setting up Calc ...240
Using Calc ...241
Entering and formatting data ...241
Calculating and charting data ...244
Chapter 3: Making Presentations with OpenOffice.org Impress . . .249
Taking Stock of OpenOffice.org Impress ...249
Getting Started with Impress ...250
Using Impress ...253
Preparing presentations ...254
Adding graphics and special effects ...257
Delivering presentations ...260
Chapter 4: Drawing with OpenOffice.org Draw . . . .261
Taking Stock of OpenOffice.org Draw ...261
Getting Started with Draw ...262
Using Draw ...264
Book IV: Networking ...269
Chapter 1: Connecting to the Internet . . . .271
Understanding the Internet ...271
Deciding How to Connect to the Internet ...272
Connecting with DSL ...274
How DSL works ...274
DSL alphabet soup: ADSL, IDSL, SDSL ...275
Typical DSL setup ...276
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Connecting with a Cable Modem ...279
How cable modem works ...280
Typical cable modem setup ...282
Setting Up Dial-Up Networking ...284
Connecting the modem ...286
Testing the modem ...289
Setting up and activating a PPP connection ...291
Configuring CHAP and PAP authentication ...293
Chapter 2: Setting Up a Local Area Network . . . .295
Understanding TCP/IP ...295
TCP/IP and the Internet ...297
IP addresses ...297
Internet services and port numbers ...298
Setting Up an Ethernet LAN ...299
How Ethernet works ...300
Ethernet cables ...301
Configuring TCP/IP Networking ...302
Connecting Your LAN to the Internet ...305
Chapter 3: Adding a Wireless Ethernet LAN . . . .307
Understanding Wireless Ethernet Networks ...307
Understanding infrastructure and ad hoc modes ...308
Understanding wired equivalent privacy (WEP) ...310
Setting Up the Wireless Hardware ...310
Configuring the wireless access point ...312
Configuring Wireless Networking ...312
Chapter 4: Managing the Network . . . .319
Learning the TCP/IP Configuration Files ...319
/etc/hosts ...320
/etc/networks ...320
/etc/host.conf ...320
/etc/resolv.conf ...321
/etc/hosts.allow ...321
/etc/hosts.deny ...322
/etc/nsswitch.conf ...323
Checking Out TCP/IP Networks ...323
Checking the network interfaces ...323
Checking the IP routing table ...324
Checking connectivity to a host ...325
Checking network status ...325
Sniffing network packets ...327
Configuring Networks at Boot Time ...328
Table of Contents xv
Chapter 5: Cool Networking Projects . . . .329
Building Your Own Home Network ...329
Things you need ...329
Steps to follow ...330
Adding Wireless to Your Current Network ...331
Things you need ...331
Steps to follow ...331
Turning Your Fedora Core System into a NAT Router ...332
Things you need ...332
Steps to follow ...333
Book V: Internet ...335
Chapter 1: Exchanging E-Mail and Instant Messages . . . .337
Understanding Electronic Mail ...338
How MUA and MTA work ...338
Mail message enhancements ...339
Taking Stock of Mail Readers and IM Clients in Fedora Core ...340
Using Ximian Evolution ...340
Using Mozilla Mail ...344
Managing your Inbox ...347
Composing and sending messages ...348
Instant Messaging with Gaim ...349
Chapter 2: Using the Web . . . .351
Discovering the World Wide Web ...351
Like a giant spider’s web ...352
Links and URLs ...353
Web servers and Web browsers ...355
Web Browsing in Fedora Core ...356
Checking out the Web browsers in Fedora Core ...357
Starting Mozilla ...357
Learning Mozilla’s user interface ...357
Changing your home page ...361
Changing Mozilla’s appearance ...361
Surfing the Net with Mozilla ...363
Creating Web Pages ...364
Introducing HTML ...364
Composing Web pages with Mozilla Composer ...366
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Chapter 3: Reading Newsgroups . . . .371
Understanding Newsgroups ...371
Newsgroup hierarchy ...372
Top-level newsgroup categories ...373
Linux-related newsgroups ...374
Reading Newsgroups from Your ISP ...375
Reading newsgroups with Mozilla Mail ...376
Newsgroup subscriptions ...378
Posting news ...379
Reading and Searching Newsgroups at Web Sites ...380
Chapter 4: Transferring Files with FTP . . . .383
Using Graphical FTP Clients ...383
Using gFTP ...384
Using a Web browser as an FTP client ...385
Using the Command-Line FTP Client ...387
Book VI: Administration ...391
Chapter 1: Performing Basic System Administration . . . .393
Taking Stock of System-Administration Tasks ...393
How to Become root ...395
Using the su - command ...395
Becoming root for the GUI Utilities ...395
Recovering from a forgotten root password ...396
Understanding How Fedora Core Boots ...397
Understanding the init process ...397
Examining the /etc/inittab file ...399
Trying a new run level with the init command ...400
Understanding the Fedora Core startup scripts ...401
Manually starting and stopping servers ...402
Automatically starting servers at system startup ...403
Understanding the GUI startup ...404
Taking Stock of Fedora Core System Configuration Files ...406
Monitoring System Performance ...408
Using the top utility ...409
Using the GNOME system monitor ...411
Using the uptime command ...412
Using the vmstat utility ...413
Checking disk performance and disk usage ...414
Viewing System Information via the /proc File System ...415
Scheduling Jobs in Fedora Core ...418
Scheduling one-time jobs ...419
Scheduling recurring jobs ...421
Table of Contents xvii
Chapter 2: Managing Users . . . .425
Adding User Accounts ...425
Using the User Manager to add user accounts ...426
Using commands to manage user accounts ...428
Understanding the /etc/passwd File ...429
Managing Groups ...430
Exploring the User Environment ...431
Changing User and Group Ownership of Files ...434
Chapter 3: Managing the File System . . . .437
Learning the Linux File System ...437
Understanding the file-system hierarchy ...438
Mounting a device on the file system ...440
Examining the /etc/fstab file ...442
Sharing Files with NFS ...443
Exporting a file system with NFS ...444
Mounting an NFS file system ...445
Backing Up and Restoring Files ...445
Selecting a backup strategy and media ...445
Commercial backup utilities for Linux ...447
Using the tape archiver — tar ...447
Accessing DOS/Windows File Systems ...452
Mounting a DOS disk partition ...452
Mounting DOS floppy disks ...453
Mounting an NTFS Partition ...455
Using mtools ...455
Trying mtools ...456
Understanding the /etc/mtools.conf file ...456
Learning the mtools commands ...457
Formatting a DOS floppy ...459
Chapter 4: Managing Applications . . . .461
Working with Red Hat Package Manager ...461
Using the RPM commands ...461
Understanding RPM filenames ...462
Finding out about RPMs ...463
Installing an RPM ...466
Removing an RPM ...467
Upgrading an RPM ...467
Verifying an RPM ...468
Building Software Packages from Source Files ...469
Downloading and unpacking the software ...469
Building the software from source files ...471
Installing SRPMS ...474
Updating Fedora Core Applications with Up2date ...474
Using Yellow dog Updater, Modified (Yum) ...475
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Chapter 5: Managing Devices and Printers . . . .479
Understanding Linux Devices ...479
Device files ...480
Persistent device naming with udev ...482
Managing Loadable Driver Modules ...482
Loading and unloading modules ...483
Using the /etc/modprobe.conf file ...485
Managing USB Devices ...486
Managing Print Queues in Fedora Core ...488
Spooling and print jobs ...488
Printing with the lp command ...490
Checking the print queue using lpq ...490
Canceling the print job using cancel ...490
Checking the printer status using lpstat ...491
Controlling the print queue ...491
Chapter 6: Upgrading and Customizing the Kernel . . . .493
Upgrading with a Kernel RPM ...494
Downloading new kernel RPMs ...494
Installing the kernel RPMs ...494
Trying out the new kernel ...495
Rebuilding the Kernel ...496
Creating a monolithic versus a modular kernel ...497
Configuring the kernel ...498
Running the kernel configuration tool ...499
Building the Kernel and the Modules ...513
Installing the Modules ...514
Creating the Initial RAM Disk File ...514
Installing the New Kernel and Setting Up GRUB ...515
Rebooting the System ...517
Book VII: Security ...519
Chapter 1: Understanding Network and Host Security . . . .521
Why Worry About Security? ...521
Establishing a Security Framework ...522
Determine business requirements for security ...523
Perform risk analysis ...524
Establish security policy ...525
Implement security solutions (mitigation) ...526
Manage security ...526
Table of Contents xix
Securing Linux ...527 Understanding the host security issues ...527 Understanding network security issues ...528 Learning Computer Security Terminology ...529 Keeping Up with Security News and Updates ...532
Chapter 2: Securing the Host . . . .535
Installing Operating System Updates ...535 Securing Passwords ...536 Shadow passwords ...536 Pluggable authentication modules (PAMs) ...537 Protecting Files and Directories ...540 Viewing ownerships and permissions ...540 Changing file ownerships ...541 Changing file permissions ...541 Setting default permission ...542 Checking for set user ID permission ...543 Using exec-shield ...544 Using SELinux ...545 Encrypting and Signing Files with GnuPG ...547 Understanding public-key encryption ...547 Understanding digital signatures ...548 Using GPG ...550 Monitoring System Security ...554
Chapter 3: Securing the Network . . . .557
Securing Internet Services ...557 Using chkconfig to disable standalone services ...558 Configuring the xinetd server to disable services ...558 Using Secure Shell (SSH) for Remote Logins ...561 Setting Up Simple Firewalls ...563 Screening the router with packet filtering ...565 Dual-homed host ...567 Perimeter network with bastion host ...568 Application gateway ...570 Enabling Packet Filtering on Your Fedora Core System ...571 Using the security level configuration tool ...572 Using the iptables command ...573
Chapter 4: Performing Security Audits . . . .577
Understanding Security Audits ...577 Nontechnical aspects of security audits ...578 Technical aspects of security audits ...579
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Learning a Security Test Methodology ...579 Some common computer vulnerabilities ...580 Host security review ...582 Network-security review ...585 Exploring Security Testing Tools ...588 Nmap ...589 Nessus ...590 SAINT ...593 SARA ...594
Book VIII: Internet Servers ...595
Chapter 1: Managing the Servers . . . .597
Understanding Internet Services ...597 TCP/IP and sockets ...598 Internet services and port numbers ...601 Using the xinetd Super Server ...603 Running Standalone Servers ...606 Starting and stopping servers manually ...606 Starting servers automatically at boot time ...607
Chapter 2: Running the Apache Web Server . . . .615
Exploring HTTP ...615 Exploring the Apache Web Server ...618 Installing the Apache Web server ...619 Starting the Apache Web server ...620 Configuring the Apache Web Server ...621 Using Apache configuration tools ...622 Apache configuration files ...623 The httpd.conf configuration file ...624 Virtual host setup ...634
Chapter 3: Setting Up the FTP Server . . . .639
Installing the FTP Server ...639 Configuring the FTP Server ...640 vsftpd configuration files ...640 /etc/vsftpd/vsftpd.conf file ...641 /etc/vsftpd.ftpusers file ...643 /etc/vsftpd.user_list file ...644 Setting Up Secure Anonymous FTP ...644 Trying Anonymous FTP ...645 Key features of anonymous FTP ...645
Table of Contents xxi
Chapter 4: Serving Up Mail and News . . . .647
Installing the Mail Server ...647 Using sendmail ...648 A mail-delivery test ...649 The mail-delivery mechanism ...649 The sendmail configuration file ...651 sendmail.cf file syntax ...659 Other sendmail files ...661 The .forward file ...662 Invoking procmail in the .forward file ...663 The sendmail alias file ...664 Installing the News Server ...665 Configuring and Starting the INN Server ...665 InterNetNews components ...666 The incoming.conf file ...670 The readers.conf file ...671 InterNetNews startup ...671 Setting Up Local Newsgroups ...672 Defining a newsgroup hierarchy ...673 Updating configuration files ...673 Adding the newsgroups ...674 Testing your newsgroups ...674
Chapter 5: Setting Up DNS . . . .675
Understanding Domain Name System (DNS) ...675 What is DNS? ...676 Learning hierarchical domain names ...677 Exploring Berkeley Internet Name Domain (BIND) ...678 Configuring DNS ...682 Configuring the resolver ...682 Configuring a caching name server ...683 Configuring a primary name server ...692
Chapter 6: Running Samba and NFS . . . .695
Sharing Files with NFS ...695 Exporting a file system with NFS ...696 Mounting an NFS file system ...698 Using the NFS Server Configuration tool ...699 Setting Up a Windows Server Using Samba ...700 Checking whether Samba is installed ...702 Configuring Samba ...703 Trying out Samba ...705
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Book IX: Programming ...707
Chapter 1: Fedora Core Programming Essentials . . . .709
Learning Programming ...709 A simplified view of a computer ...710 Role of the operating system ...711 Basics of computer programming ...712 Exploring the Software Development Tools in Fedora Core ...713 GNU C and C++ compilers ...714 The GNU make utility ...718 The GNU debugger ...725 Understanding the Implications of GNU Licenses ...732 The GNU General Public License ...732 The GNU Library General Public License ...733
Chapter 2: Programming in C . . . .735
The Structure of a C Program ...735 Preprocessor Directives ...737 Including files ...738 Defining macros ...738 Declaration and Definition of Variables ...741 Basic data types ...741 Enumerations ...742 Structures, Unions, and Bit Fields ...743 Arrays ...743 Pointers ...744 Type definitions ...745 Type qualifiers: const and volatile ...746 Expressions ...747 Operator Precedence ...749 Statements ...751 The break statement ...751 The case statement ...752 A compound statement or block ...752 The continue statement ...752 The default label ...753 The do statement ...753 Expression statements ...753 The for statement ...753 The goto statement ...754 The if statement ...754 The if-else statement ...754 The null statement ...755 The return statement ...755
Table of Contents xxiii
The switch statement ...755 The while statement ...756 Functions ...757 Function prototypes ...757 The void type ...758 Functions with a variable number of arguments ...758 The C Library ...758 Shared Libraries in Linux Applications ...760 Examining shared libraries that a program uses ...760 Creating a shared library ...762 Dynamically loading a shared library ...764
Chapter 3: Writing Shell Scripts . . . .767
Trying Out Simple Shell Scripts ...767 Learning the Basics of Shell Scripting ...770 Storing stuff ...770 Calling shell functions ...771 Controlling the flow ...772 Exploring Bash’s built-in commands ...775
Chapter 4: Programming in Perl . . . .779
Understanding Perl ...779 Determining Whether You Have Perl ...780 Writing Your First Perl Script ...782 Getting an Overview of Perl ...783 Basic Perl syntax ...783 Variables ...784 Operators and expressions ...787 Regular expressions ...789 Flow-control statements ...791 Accessing Linux commands ...795 File access ...797 Filename with pipe prefix ...798 Subroutines ...799 Built-in functions in Perl ...800 Understanding Perl Packages and Modules ...800 Perl packages ...801 Perl modules ...802 Using a module ...803 Using Objects in Perl ...804 Understanding Perl Objects ...804 Creating and accessing Perl objects ...805 Using the English module ...806
Red Hat Fedora Linux 2 All-in-One Desk Reference For Dummies
xxiv
Appendix: About the DVD ...807
DVD Installation Instructions ...807 What You Can Find on the DVD ...809 Troubleshooting ...810
Index...811
Introduction
R
ed Hat has recently decided to discontinue the Red Hat Linux product line and instead focus on the commercial Red Hat Enterprise Linux — RHEL — product line. The evolution of the now-defunct Red Hat Linux product line continues on as the Fedora Project, a Red Hat-sponsored and community-supported open source project that continues to evolve what once was Red Hat Linux. What comes out of the Fedora Project is a Fedora Core release every six months or so. (For example, Fedora Core 1 came out in November 2003 and Fedora Core 2 was released in May 2004.) In contrast to the rapid Fedora Core release cycles, RHEL is a stable product line with a 12 to 18 month release cycle and five years of support for every version.New technologies that first appear in Fedora Core will eventually find their way into the next-generation Red Hat Enterprise Linux (RHEL) product.
Thus, Fedora Core releases are a precursor to what’s coming in RHEL in the future.
The recently released Fedora Core 2 comes with many new system compo- nents including the Linux 2.6.5 kernel, X.Org X11 6.7.0, GNOME 2.6, KDE 3.2.2, GCC 3.3 compiler, and the glibc 2.3.3 system libraries. This version supports many new features such as Advanced Configuration and Power Interface (ACPI), Bluetooth wireless connections, and a graphical boot screen that shows system startup messages in a user-friendly screen.
Fedora Core 2 also includes the OpenOffice.org 1.1.1 office suite. To top it off, Fedora Core continues to come with a graphical installation program that makes installation easy!
About This Book
Red Hat Fedora Linux 2 All-in-One Desk Reference For Dummiesgives you nine different quick-reference guides in a single book. Taken together, these nine books provide detailed information on installing, configuring, and using Fedora Core.
What you’ll like most about this book is that you don’t have to read it sequentially chapter by chapter, or, for that matter, even the sections in a chapter. You can pretty much turn to the topic you want and quickly get the answer to your pressing questions about Fedora Core, be it about using the OpenOffice.org word processor or setting up the Apache Web server.
Conventions Used in This Book
2
Here are some of the things you can do with this book:
✦ Install and configure Fedora Core from the DVD-ROM included with the book.
✦ Connect the Fedora Core PC to the Internet through a DSL or cable modem.
✦ Set up dial-up networking with PPP.
✦ Get tips, techniques, and shortcuts for specific uses of Fedora Core, such as
• Setting up and using Internet services such as Web, Mail, News, FTP, NFS, and DNS.
• Setting up a Windows server using Samba.
• Using Linux commands.
• Using Perl, shell, and C programming on Linux.
• Using the OpenOffice.org office suite and other applications that come with Fedora Core.
✦ Understand the basics of system and network security.
✦ Perform system administration tasks.
Conventions Used in This Book
I use a simple notational style in this book. All listings, filenames, function names, variable names, and keywords are typeset in a monospacefont for ease of reading. I italicize the first occurrences of new terms and concepts and then provide a definition right there. The output of commands follows the typed command and the output is shown in a monospace font.
What You Don’t Have to Read
Each mini reference book zeros in on a specific task area such as using the Internet or running Internet servers and then provides hands-on instructions on how to perform a series of related tasks. You can jump right to a section and read about a specific task. You don’t have to read anything but the few paragraphs or the list of steps that relate to your question. Use the Table of Contents or the Index to locate the pages relevant to your question.
You can safely ignore text next to the Technical Stuff icons as well as the sidebars.
How This Book Is Organized 3 Who Are You?
I assume that you are somewhat familiar with a PC — you know how to turn it on and off and you have dabbled a bit with Windows. Considering that most new PCs come preloaded with Windows, this assumption is safe, right?
When installing Fedora Core on your PC, you may want to retain your Windows 2000 or Windows XP installations intact. I assume you don’t mind investing in a good disk-partitioning tool such as PowerQuest’s PartitionMagic, available at www.powerquest.com/partitionmagic (no, I don’t have any connections with PowerQuest).
I also assume that you are willing to accept the risk that when you try to install Fedora Core, some things may not quite work. Problems can happen if you have some uncommon types of hardware. If you are afraid of ruining your system, try finding a slightly older spare Pentium PC that you can sac- rifice and then install Fedora Core on that PC.
How This Book Is Organized
Red Hat Fedora Linux 2 All-in-One Desk Reference For Dummieshas nine books, each of which focuses on a small set of related topics. If you are looking for information on a specific topic, check the book names on the spine or con- sult the Table of Contents.
This desk reference starts with a minibook that explains the basics of Fedora Core and guides you through the installation process (a unique aspect of this book because you typically do not purchase a PC with Fedora Core pre- installed). The second minibook serves as a user’s guide to Fedora Core — it focuses on exploring various aspects of a Fedora Core workstation, including the GNOME and KDE GUIs and many of the applications that come bundled with Fedora Core. The third minibook is a user’s guide to the OpenOffice.org office applications. The fourth minibook covers networking and Book V goes into using the Internet. Book VI introduces system administration. The sev- enth minibook turns to the important subject of securing a Fedora Core system and its associated network. Book VIII shows you how to run a vari- ety of Internet servers from mail to a Web server. The ninth and final mini- book introduces you to programming.
Here’s a quick overview of the nine books and what they contain:
Book I: Fedora Basics:What is Fedora Core? Understanding what’s new in the Linux 2.6 kernel. Installing, configuring, and troubleshooting Fedora Core. Taking Fedora Core for a test drive.
What’s on the DVD?
4
Book II: Workstations and Applications:Exploring GNOME and KDE. Using the shell (what’s a shell anyway?). Navigating the Fedora Core file system.
Exploring the applications such as multimedia software as well as the text editors (viand ed).
Book III: OpenOffice.org:Writing with OpenOffice.org Writer. Preparing spreadsheets with OpenOffice.org Calc. Making presentations with OpenOffice.org Impress. Preparing drawings with OpenOffice.org Draw.
Book IV: Networking:Connecting the Fedora Core PC to the Internet through a dial-up connection or a high-speed always-on connection such as DSL or cable modem. Configuring and managing TCP/IP networks, including wire- less networks.
Book V: Internet:Using various Internet services such as e-mail, Web surf- ing, and reading newsgroups. Transferring files with FTP.
Book VI: Administration:Performing basic system administration. Managing user accounts and the file system. Installing applications. Working with devices and printers. Using USB devices. Upgrading and customizing the Linux kernel.
Book VII: Security:Understanding network and host security. Securing the host and the network. Performing security audits.
Book VIII: Internet Servers:Managing the Internet services. Configuring the Apache Web server. Setting up the FTP server (including anonymous FTP).
Configuring the mail and news servers. Providing DNS. File sharing with NFS.
Using Samba to set up a Windows server.
Book IX: Programming:Finding out the basics of programming. Exploring the software development tools in Fedora Core. Writing shell scripts. Learning C and Perl programming.
Appendix: About the DVD:Summarizes the contents of the book’s compan- ion DVD-ROM.
What’s on the DVD?
The DVD contains Fedora Core 2 from the Fedora Project (fedora.redhat.
com). You may use the DVD in accordance with the license agreements accompanying the software. To discover more about the contents of the DVD, please consult the appendix.
Where to Go from Here 5
Icons Used in This Book
Following the time-honored tradition of the All-in-One Desk Reference For Dummiesseries, I use icons to help you quickly pinpoint useful information.
The icons include the following:
The Remember icon marks a general interesting fact — something that I thought you want to know and remember.
The Tip icon marks things that you can do to make your job easier.
The Warning icon highlights potential pitfalls. With this icon, I’m telling you:
“Watch out! This could hurt your system!”
The Technical Stuff icon marks technical information that could be of inter- est to an advanced user (or those of us aspiring to be advanced users).
Where to Go from Here
It’s time to get started on your Fedora Core adventure. Take out the DVD and install Fedora Core. Then, turn to a relevant chapter and let the fun begin. Use the Table of Contents and the Index to figure out where you want to go. Before you know it, you’ll become an expert at Fedora Core!
If you want to participate in the Fedora Core project, visit the project’s Web site at fedora.redhat.comfor more information.
I hope you enjoy consulting this book as much as I enjoyed writing it!
Sidebars
I use sidebars throughout the book to highlight interesting, but not critical, information. Sidebars explain concepts you may not have encountered
before or give a little insight into a related topic.
If you’re in a hurry, you can safely skip the sidebars.
Red Hat Fedora Linux 2 All-in-One Desk Reference For Dummies
6
Book I
Fedora Basics
Contents at a Glance
Chapter 1: Introducing Fedora Core ...9 Chapter 2: Installing Fedora ...31 Chapter 3: Troubleshooting and Configuring Fedora Core ...57 Chapter 4: Trying Out Fedora Core ...75 Chapter 5: Cool Fedora Install Projects ...99
Chapter 1: Introducing Fedora Core
In This Chapter
Explaining what Fedora Core is Going over what Fedora Core includes
Discovering what Fedora Core helps you manage Getting started
I
bet you’ve heard about Linux and you probably know about Red Hat Linux as well, but chances are Fedora Core is new to you. If you’re won- dering what exactly Fedora Core is and what it can help you do, this chapter is all about answering those questions. Here I provide a broad-brushstroke picture of Fedora Core and tell you how you can start using it right away.By the way, this book covers Fedora Core for Intel 80x86 and Pentium processors (basically any PC that can run any flavor of Windows).
What Is Fedora Core?
Fedora Core is what used to be Red Hat Linux — the Linux distribution from Red Hat that used to be available free of charge. If you never knew Red Hat Linux, think of Fedora Core as another Linux distribution. That leaves you with the question: What is a Linux distribution anyway?
Trying to describe a Linux distribution is a bit like that story of six blind men trying to describe an elephant. You know the one — one blind man touches the elephant’s side and says the elephant is like a wall, another checks out the tusk and concludes that an elephant is like a spear, and so on. Along those lines, a Linux distribution appears to be many different things, depending on what you experience. You can think of it as the graph- ical user interface or just a PC to run your e-mail program, but, at its heart, it’s an operating system. The following sections explain what I mean by this statement.
Operating systems and Linux
You know that your PC is a bunch of hardware— things you can touch, like the system box, monitor, keyboard, and mouse. The system box contains the most important hardware of all — the central processing unit(CPU), the microchip that runs the software (any program that tells the computer how
What Is Fedora Core?
10
to do your bidding) — which you actually can’ttouch. In a typical Pentium 4 PC, the Pentium 4 microprocessor is the CPU. Other important hardware in the system box includes the memory (RAM chips) and the hard drive — and one program has to run all this stuff and get it to play nice: the operating system.
The operating systemis software that manages all the hardware and runs other software at your command. You, the user, provide those commands by clicking menus and icons or by typing some cryptic text. Linux is an oper- ating system — as are UNIX, Windows 98, Windows 2000, and Windows XP.
The Linux operating system is modeled after UNIX; in its most basic, no-frills form, it also goes by the name Linux kernel.
The operating system is what gives a computer — any computer — its per- sonality. For example, you can run Windows 98 or Windows XP on a PC — and on that same PC, you can alsoinstall and run Linux. That means, depend- ing on which operating system is installed and running, the same PCcan be a Windows 98, Windows XP, or Linux system.
The primary job of an operating system is to load software (computer pro- grams) from the hard disk (or other permanent storage) into the memory and get the CPU to run those programs. Everything you do with your com- puter is possible because of the operating system — so if the operating system somehow messes up, the whole system freezes up. You know how infuriating it is when your favorite operating system — maybe even the one that came with your PC — suddenly calls it quits just as you are about to click the Send button after composing that long e-mail to your friend. You try the three-finger salute (pressing Ctrl+Alt+Del), but nothing happens. Then it’s time for the Reset button (provided your computer’s builders were wise enough to include one). Luckily, that sort of thing almost never happens with Linux — it has a reputation for being a very reliable operating system.
Does Linux really run on any computer?
Linux runs on many different types of computer systems — and it does seem able to run on nearly any type of computer. Linus Torvalds and other programmers originally developed Linux for the Intel 80x86 (and compatible) line of processors. Nowadays, Linux is also available for systems based on other processors — such as those with AMD’s 64-bit AMD64 processors, the Motorola 68000 family; Alpha AXPs; Sun
SPARCs and UltraSPARCs; Hewlett-Packard’s HP PA-RISC; the PowerPC and PowerPC64 processors; and the MIPS R4x00 and R5x00.
More recently, IBM has released its own ver- sion of Linux for its S/390 mainframe. This book covers Linux for Intel 80x86 and Pentium proces- sors (these have in common a basic physical structure known as IA-32 architecture).
Book I Chapter 1
IntroducingFedoraCore
What Is Fedora Core? 11
In technical mumbo jumbo, Linux is a multiuser, multitasking operating system.
All this means is that Linux enables multiple users to log in, and Linux can run more than one program at the same time. Nearly all operating systems are multiuser and multitasking these days, but when Linux first started in 1994, multiuserand multitaskingwere big selling points.
Linux distributions
Fedora Core is a specific Linux distribution— essentially a package of fea- tures. Fedora Core consists of the Linux kernel(the operating system) and a collection of applications, together with an easy-to-use GUI installation program, called Anaconda.
You find many Linux distributions, and each includes the standard Linux operating system:
✦ The X.Org X Window System:The graphical user interface.
✦ One or more graphical desktops:Among the most popular are GNOME and KDE.
✦ A selection of applications:Linux programs come in the form of ready-to- run software, but the source code(the commands we humans use to tell the computer what to do, but you don’t need the source code to run the operating system or any applications) is included, as is its documentation.
Current Linux distributions include a huge selection of software — so much that it requires multiple CD-ROMs or a single DVD-ROM (which this book includes).
Many Linux distributions are commercial products that you can buy in com- puter stores and bookstores. If you have heard about Open Source and the GNU (GNU’s Not UNIX) license, you may assume that no one can sell Linux for profit. Luckily for companies that sell Linux distributions, the GNU license — also called the GNU General Public License (GPL) — does allow commercial, for-profit distribution, but requires that the software be dis- tributed in source-code form, and stipulates that anyone may copy and distribute the software in source-code form to anyone else. Fedora Core is available free of charge under the GPL, which means that my publisher may include the Fedora Core DVD-ROM with this book and you may make as many copies of the DVD as you like.
Transitioning to the Fedora Project
In late September 2003, Red Hat announced the Fedora Project — an open- source project sponsored by Red Hat where the developer community can participate and continue to evolve what used to be the Red Hat Linux prod- uct. The new product goes by the name Fedora Coreand the project is expected to have Fedora Core releases every four to six months. Red Hat
What Is Fedora Core?
12
continues to participate in the Fedora Project and help prepare the Fedora Core releases, but everything is done with involvement of the open source community under a public release schedule. As you may expect, Fedora Core is available freely, just as Red Hat Linux used to be, and you can expect books such as this one to include Fedora Core on DVD or CDs.
Red Hat continues to sell its commercial Linux distribution — called Red Hat Enterprise Linux. Red Hat anticipates that new technologies and enhance- ments that first appear in Fedora Core will eventually find their way into Red Hat Enterprise Linux. In this way, the Fedora Project serves as an incubator and testing ground for future Linux development.
To find out more about the Fedora Project, visit fedora.redhat.com.
Making sense of version numbers
Both the Linux kernel and Fedora Core have their own version numbers, not to mention the many other software programs (such as GNOME and KDE) that come with Fedora Core. The version numbers for the Linux kernel and Fedora Core are unrelated, but each has particular significance.
Linux-kernel version numbers
After Linux kernel version 1.0 was released on March 14, 1994, the loosely knit Linux development community adopted a version-numbering scheme.
Version numbers such as 1.X.Yand 2.X.Y,where Xis an even number, are considered the stable versions. The last number, Y,is the patch level, which is incremented as problems are fixed. For example, 2.6.5 is a typical, stable version of the Linux kernel. Notice that these version numbers are in the form of three integers separated by periods —Major.Minor.Patch— where Majorand Minorare numbers denoting the major and minor version num- bers, and Patchis another number representing the patch level.
Version numbers of the form 2.X.Ywith an odd Xnumber are beta releases for developers only; they may be unstable, so you should not adopt such versions for day-to-day use. For example, when you look at version 2.5.75 of the Linux kernel, notice the 5— that tells you it’s a beta release. Developers add new features to these odd-numbered versions of Linux.
You can find out about the latest version of the Linux kernel online at www.kernel.org.
Fedora Core version numbers
The Fedora Core development community, led by Red Hat, assigns the Fedora Core version numbers, such as 1 or 2. They are of the form X.Y,where Xis the major version and Ythe minor version. Nowadays if the minor version number is zero, it’s simply dropped — as in Fedora Core 1 and Fedora Core 2.
Book I Chapter 1
IntroducingFedoraCore
What Is Fedora Core? 13
Unlike with the Linux-kernel version numbers, no special meaning is associ- ated with odd and even minor versions. Each version of Fedora Core includes specific versions of the Linux kernel and other major components, such as GNOME, KDE, and various applications.
The Fedora Project releases new versions of Fedora Core on a regular basis — every six months or so. For example, Fedora Core 1 came out in November 2003 and Fedora Core 2 in May 2004. Typically, each new major version of Fedora Core provides significant new features.
Under the hood in Linux kernel 2.6
Linux kernel 2.6 includes many new features and improvements when com- pared to its predecessor — the 2.4 kernel. I highlight some of these improve- ments in this section. You may not notice many of these improvements because they work behind the scenes. All you see is a Linux system that simply works great!
Support for wider range of computer hardware
For starters, the 2.6 kernel has been redesigned to support computers span- ning a wider range of hardware than before — from bare-bones embedded microcontrollers to larger-scale servers with multiple processors.
To support distinct hardware architectures of the same processor family (such as x86), Linux 2.6 uses the concept of a subarchitecture,which refers to the processor and the associated bus and other hardware that defines a unique type of computer. For example, most of today’s PCs are based on what is called the PC/AT subarchitecture because these PCs are based on the original IBM PC/AT. The 2.6 kernel supports PC/AT machines as well as other x86 subarchitectures, such as the NEC Voyager and the PC-9800 machines. The bottom line is that the 2.6 kernel can run on many variations of the x86-based machines.
Linux 2.6 also supports advanced features of processors such as hyperthread- ing, which enables a single processor to act as multiple virtual processors at the hardware level.
Better scalability
The 2.6 kernel provides better scalability for Intel x86 hardware by support- ing advanced features such as Intel’s Physical Address Extension (PAE), which enables many newer 32-bit x86 systems to access up to 64GB of memory.
Linux 2.6 also provides better handling of interrupts for multiprocessor sys- tems through improved support for Intel’s Input/Output (I/O) Advanced Programmable Interrupt Controller (APIC).
What Is Fedora Core?
14
Internally, the 2.6 kernel raises many internal limits from number of users to the maximum number of open files. For example, the number of unique users and groups has been increased from 65,536 to over 4 billion. The maximum number of open files can now grow as needed. File systems can be as large as 16TB (that’s about 16,000 gigabytes! ).
Linux 2.6 also increases the limits on the major and minor device numbers, which used to be a maximum of 255 in earlier kernels. These device numbers translate to 255 device types and 255 devices of a single type. In kernel ver- sion 2.6, the major device numbers can be up to 4,095 and minor device numbers can be more than a million. The upshot is that Linux 2.6 can sup- port many more device types and many devices of a single type.
Improved device handling
Linux 2.6 has a number of new features for handling devices — especially hot plug devices such as the ones that connect to USB and Firewire inter- faces common in today’s PCs. First, the kernel uses a new virtual file system called sysfsthat is meant to hold information about the devices on the system.
The sysfs file system mounts on /sysand it presents a hierarchical view of all the devices organized by device type, bus, and so on. Through sysfs, the 2.6 kernel makes available to other applications a lot of information about devices, including the name of a device, resources such as interrupts and I/O ports used by the device, the power status of the device, and so on.
By using the sysfs capabilities available in the 2.6 kernel, a separate device- handling program called udevcan now dynamically add device files when a device is added to a system. The udevprogram is invoked by the /sbin/
hotplugshell script that runs when any hot plug device such as a USB device is plugged into the computer. udevgives each device a name that stays the same every time that device connects to the system. In Fedora Core, udevis not configured by default to manage the device files in the /devdirectory. Instead udevmanages device files in the /udevdirectory.
However, you can easily configure udev(through the /etc/udev/udev.
conffile) to manage the device files in /devdirectory.
Other device-handling improvements in Linux 2.6 include ensuring that device driver modules are not unloaded while still in use and standardiz- ing the way in which device drivers make available information about devices they support. All device driver module filenames now use the .koextension — for kernel object— instead of the generic .oextension commonly used for object files.
Linux 2.6 also has improved support for many devices such as USB 2.0 and wireless devices. As for storage devices, the Integrated Drive Electronics (IDE) — also called AT Attachment (ATA) — and Small Computer System Interface (SCSI) support was updated in Linux 2.6. For example, IDE
Book I Chapter 1
IntroducingFedoraCore
What Is Fedora Core? 15
CD-recorders are now accessed through the IDE driver instead of a special SCSI-emulation driver that was used in earlier versions of the kernel. The 2.6 kernel also supports the new Serial ATA (SATA) interface that can support data transfer rates of 150MB per second.
Mandatory access control with Security Enhanced Linux (SELinux)
Linux kernel 2.6 includes the mandatory access control framework provided by Security Enhanced Linux (SELinux), which was developed by the National Security Agency (NSA), a U.S. government agency. SELinux is implemented as a Linux Security Module (LSM) — an extension of the Linux kernel that allows security mechanisms to be easily added to the kernel. You can find more about SELinux at the NSA’s Web site, www.nsa.gov/selinux/. Without SELinux, access control in Linux is based on the user and group ID that owns a process or a file. In this discretionary access control approach, the superuser (root) has absolute discretion to access and do anything on the system. In contrast to this approach, SELinux views the system in terms of subjects(users or processes) and objects(files, devices, any system resources). Subjects can take on different rolessuch as normal user or system administrator. Each subject also has a domainand each object has atype. SELinux provides fine-grained control over who can access what in a Linux system by defining what domains can access what types and how one domain can transition into another when programs execute.
The mandatory access control rules are defined in the SELinux security policy. To support the fine-grained access control, all files need additional attributes called contextsthat are stored in labels added to the files. Think of the contexts as information on which roles can access and do what with the file. When SELinux is enabled, all files in the file system have to be labeled with the security contexts. Only then can SELinux manage the fine-grained access control.
When you install Fedora Core, you can type selinuxat the installer’s boot:
prompt to install SELinux and select the level of access control you want SELinux to enforce. This option appears in the screen where you configure the firewall.
Note:SELinux can be very helpful in securing your organization’s external Web and e-mail servers that are exposed to the Internet and, therefore, sub- ject to attacks. With a well-designed security policy, SELinux can make such Internet-facing servers resistant to damage from attacks, even if an attacker manages to gain superuser privileges. However, the additional effort involved in setting up and running SELinux may not be worthwhile for internal servers not directly connected to the Internet.
What Fedora Core Includes
16
What Fedora Core Includes
Fedora Core comes with the Linux kernel and a whole lot more software.
These software packages include everything from the graphical desktops to Internet servers and programming tools to create new software. In this sec- tion, I briefly describe some major software packages that come bundled with Fedora Core. Without this bundled software, Fedora Core wouldn’t be as popular as it is today.
GNU software
I start with a collection of software that came from the GNU Project. You get to know these GNU utilities only if you use your Fedora Core system through a text terminal (or a graphical window that mimics one) — a basic command- line interfacethat puts nothing much on-screen but a prompt at which you type in your commands. The GNU software is one of the basic parts of Fedora Core.
As a Fedora Core user, you may not realize the extent to which Fedora Core (and, for that matter, all Linux distributions) relies on GNU software. Nearly all tasks you perform in a Fedora Core system involve one or more GNU soft- ware packages. For example, the GNOME graphical user interface (GUI) and the command interpreter (that is, the Bash shell) are both GNU software pro- grams. By the way, the shellis the command-interpreter application that accepts the commands you type and runs programs in response to those commands. If you rebuild the kernel or develop software, you do so with the GNU C and C++ compiler (which is part of the GNU software that accompa- nies Fedora Core). If you edit text files with the edor emacs editor, you’re again using a GNU software package. The list goes on and on.
What is the GNU Project?
GNU is a recursive acronym that stands for GNU’s Not UNIX. The GNU Project was launched in 1984 by Richard Stallman to develop a complete UNIX-like operating system. The GNU Project developed nearly everything needed for a complete operating system except for the operating system kernel. All GNU soft- ware was distributed under the GNU General Public License (GPL). GPL essentially requires that the software is distributed in source-code form and stipulates that any user may copy, modify, and distribute the software to anyone
else in source-code form. Users may, however, have to pay for their individual copies of GNU software.
The Free Software Foundation (FSF) is a tax- exempt charity that raises funds for work on the GNU Project. To find out more about the GNU Project, visit its home page at www.gnu.org. You can find information about how to contact the Free Software Foundation and how to help the GNU Project.
