Chapter 1

An Overview of Red Hat Linux

In This Chapter

Introducing Red Hat Linux

What is Linux?

Linuxs roots in UNIX

Common Linux features

Primary advantages of Linux

What is Red Hat Linux?

Why choose Red Hat Linux?

The culture of free software

Linux was a phenomenon waiting to happen. The computer industry suffered from a rift. In the 1 980s and I 990s, people had to choose between inexpensive, market-driven PC operating systems from Microsoft and expensive, technology-driven operating systems such as UNIX. Free software was being created all over the world, but lacked a common platform to rally around. Linux has become that common platfonn.

Red Hat Linux is the most popular commercial distribution of Linux. Red Hat and other commercial distributions, such as Calderas OperiLinux, have taken the Linux concept a step further. With Red Hat Linux, users no longer have to download, compile, and check Linux source code to make sure that all the right pieces are put together for Linux to work. Basically, Red Hat has made it possible for Linux to be used by people other than computer geeks.

Red Hat Linux has also made Linux a more viable alternative for corporate users. Many companies have felt insecure about relying on a free operating system to handle their critical data. With Red Hat Linux, they can rely on Red Hat Software, Inc. (www. redhat . corn) to provide tested versions of that software and technical support if there are problems.

Introducing Red Hat Linux

Red Hat Linux 8 represents a bold new direction for the most popular commercial Linux distribution. While continuing to add powerful, professional server features, Red Hat Inc. has made a major move on the desktop as well. Highlights of desktop enhancements in Red Hat 8 include:

Providing a.more common Red Hat look and feel across the KDE and GNOME desktops that come with the distribution.

Adding and enhancing home-grown Red Hat graphical administrative tools, to simplify administrative tasks.

With Red Hat Linux 8, whether you use KDE or GNOME as your desktop environment, you can expect to see many of the same icons and menus to help standardize how you use your Red Hat Linux system. Tools you can launch from those environments help you configure your network, set up servers, watch log files, and manage system services.

Nearly 1,500 individual software packages (compared to just over 600 in Red Hat Linux 6.2) are included in this latest release. These packages contain features that would cost you hundreds or thousands of dollars to duplicate if you bought them as separate commercial products. These features let you:

Connect your computers to a LAN or the Internet.

Create documents and publish your work on paper or on the Web.

Work with multimedia content to manipulate images, play MPEG music files, view video, and even bum your own CDs.

Play games individually or over a network.

Communicate over the Internet using a variety of Web tools for browsing, chatting, transferring files, participating in newsgroups, and sending and receiving e-mail.

Configure a computer to act as a network server, such as a print server, Web server, file server, mail server, news server, and a database server.

This is just a partial list of what you can do with Red Hat Linux. Using this book as your

guide, you will find that there are many more features built into Red Hat Linux as well.

Support for new video cards, printers, storage devices, and applications are being added every day. Linux programmers around the world are no longer the only ones creating hardware drivers. Every day more hardware vendors are creating their own drivers, so they can sell products to the growing Linux market. New applications are being created to cover everything from personal productivity tools to programs that access massive corporate databases.

Remember that old Pentium computer in your closet? Dont throw it away! Just because a new release of Red Hat Linux is out doesnt mean that you need all new hardware for it to run.

Support for many old computer components get carried from one release to the next. There are old PCs running Red Hat Linux today as routers (to route data between your LAN and the Internet), firewalls (to protect your network from outside intrusion), and file servers (to store shared files on your LAN) with maybe an Ethernet card or an extra hard disk added.

At this point, you may feel that Linux is something you want to try out. This brings us to the basic question: What is Linux?

What Is Linux?

Linux is a free operating system that was created by Linus Torvalds when he was a student at the University of Helsinki in 1991. Torvalds started Linux by writing a kernel the heart of the operating system partly from scratch and partly by using publicly available software. (For the definition of an operating system and a kernel, see the sidebar What Is an Operating System? later in this chapter.) Torvalds then released the system to his friends and to a community of hackers on the Internet and asked them to work with it and enhance it. It took off.

CROSS-REFERENCE: See Chapter 14 for a discussion about the difference between hackers (people who just like to play with computers) and crackers (people who break into computer systems and cause damage).

Today, there are hundreds of software developers around the world contributing software to the Linux effort. Because the source code for the software is freely available, anyone can work on it, change it, or enhance it. On top of the Linux kernel effort, the creators of Linux also drew on a great deal of system software and applications that are now bundled with Linux from the GNU software effort (GNU stands for GNU is Not UNIX), which is directed by the Free Software Foundation (FSF). There is a vast amount of software that can be used with Linux, all of which includes features that can compete with or surpass those of any other operating system in the world.

If you have heard Linux described as a free version of UNIX, there is good reason for it. Although much of the code for Linux started from scratch, the blueprint for what the code would do was created to follow POSIX standards. POSIX (Portable Operating System Interface for UNIX) is a computer industry operating system standard that every major version of UNIX complied with. In other words, if your operating system was POSIX-compliant, it was UNIX. See the next section describing Linuxs roots in the UNIX operating system.

Linuxs Roots in UNIX

Linux grew within a culture of free exchange of ideas and software. Like UNIX the operating system on which Linux is based the focus was on keeping communications open among software developers. Getting the code to work was the goal, without much concern

about who owned the code, and the Internet was the primary communications medium. What, then, were the conditions that made the world ripe for a computer system such as Linux?

In the l980s and 1990s, while Microsoft flooded the world with personal computers running DOS and Windows operating systems, power users demanded more from an operating system. They ached for systems that could run on networks, support many users at once (multiuser),and run many programs at once (multitasking). DOS (Disk Operating System) and Windows

didnt cut it.

UNIX, on the other hand, grew out of a culture where technology was king and marketing people were, well, hard to find. Bell Laboratories in Murray Hill, New Jersey, was a think tank where ideas came first and profits were somebody elses problem. A quote from Dennis Ritchie, co-creator of UNIX and designer of the C programming language, in a 1980 lecture on the evolution of UNIX, sums up the spirit that started UNIX. He was commenting on both his hopes and those of his colleagues for the UNIX project after a similar project called Multics had just failed:

we wanted to preserve was notjust a good en vironment in which to do programming, but a system around which afeiowsh~p couldfo~m. We knew from experience that the essence ofcommunal computing as supplied by remote-access, time-shared machines, is not just to type programs into a terminal instead ofa keypunch, but to encourage close communication.

In that spirit, the first source code of UNIX was distributed free to universities. Like Linux, the availability of UNIX source code made it possible for a diverse population of software developers to make their own enhancements to UNIX and share them with others.

By the early l980s, UNIX development moved from the organization in Murray Hill to a more commercially oriented development laboratory in Summit, New Jersey (a few miles down the road). During that time, UNIX began to fmd commercial success as the computing system of choice for applications such as AT&Ts telephone switching equipment, for supercomputer applications such as modeling weather patterns, and for controlling NASA space projects.

Major computer hardware vendors licensed the UNIX source code to run on their computers. To try to create an environment of fairness and community to its OEMs (original equipment manufacturers), AT&T began standardizing what these different ports of UNIX had to be able to do to still be called UNIX. To that end, compliance with POSIX standards and the AT&T UNIX System V Interface Definition (SVID) were specifications UNIX vendors could use to create compliant UNIX systems. Those same documents also served as road maps for the creation of Linux.

Common Linux Features

No matter what version of Linux you use, the piece of code common to all is the Linux kernel. Although the kernel can be modified to include support for the features you want, every Linux kernel can offer the following features:

Multiuser Not only can you have many user accounts available on a Linux system, you can also have multiple users logged in and working on the system at the same time. Users can have their own environments arranged the way they want: their own home directory for storing files and their own desktop interface (with icons, menus, and

applications arranged to suit them). User accounts can be password-protected, so that users can control who has access to their applications and data.

Multitasking In Linux, it is possible to have many programs running at the same time, which means that not only can you have many programs going at once, but that the Linux operating system can itself have programs running in the background. Many of these system processes make it possible for Linux to work as a server, with these background processes listening to the network for requests to log in to your system, view a Web page, print a document, or copy a file. These background processes are referred to as daemons.

Graphical User Interface (X Window System) The powerful framework for working with graphical applications in Linux is referred to as the X Window System (or simply X). X handles the functions of opening X-based graphical user interface (GUI) applications and displaying them on an X server process (the process that manages your screen, mouse, and keyboard).

On top of X, you use an X-based desktop environment to provide a desktop metaphor and window manager to provide the look-and-feel of your GUI (icons, window frames, menus, and colors, or a combination of those items called themes). There are several desktop environments and several desktop managers to choose from. (Red Hat provides a few desktop managers, but focuses on GNOME and KDE desktop environments.)

Rardware support You can configure support for almost every type of hardware that can be connected to a computer. There is support for floppy disk drives, CD-ROMs, removable disks (such as DVDs and Zip drives), sound cards, tape devices, video cards, and most anything else you can think of.

IOTE: Not every hardware manufacturer provides Linux drivers with their peripheral devices and adapter ards. Although most popular hardware will be supported eventually in Linux, it can some~mes take a while DI 8 member of the Linux community to write a driver.

Networking connectivity To connect your Linux system to a network, Linux offers support for a variety of Local Area Network (LAN) boards, modems, and serial devices. In addition to LAN protocols, such as Ethernet (both wired and wireless) and Token Ring protocols, all the most popular upper-level networking protocols can be built-in. The most popular of these protocols is TCP/IP (used to connect to the Internet). Other protocols, such as IPX (for Novell networks) and X.25 (a packet-switching network type that is popular in Europe), are also available.

Network servers Providing networking services to the client computers on the LAN or to the entire Internet is what Linux does best. A variety of software packages are available that enable you to use Linux as a print server, file server, FTP server, mail server, Web server, news server, or workgroup (DHCP or NIS) server.

Application support Because of compatibility with POSIX and several different application programming interfaces (APIs), a wide range of freeware and shareware

software is available for Linux. Most GNU software from the Free Software Foundation will run in Linux.

NOTE: Because of the popularIty of the Red Hat Package Management (RPM) format for packaging software, many software packages are available on the Internet in RPM format. If the RPM version matches your processor type you can install the package without building and compiling the package See Chapter 5 for information on working with RPM packages.

Primary Advantages of Linux

When compared to different commercially available operating systems, Linuxs best assets are its price and its reliability. Most people know that its initial price is free (or at least under $100 when it comes in a box or with a book). However, when people talk about Linuxs affordability, they are usually thinking of its total cost, which includes the capability of using inexpensive hardware and compatible free add-on applications. Although commercial operating systems tend to encourage upgrading to later hardware, Linux doesnt (although faster hardware and larger disks are nice to have).

In terms of reliability, the general consensus is that Linux is comparable to many commercial UNIX systems but more reliable than most desktop-oriented operating systems. This is especially true if you rely on your computer system to stay up because it is a Web server or a file server. (You dont have to reboot every time you change something.)

Another advantage of using Linux is that help is always available on the Internet. There is probably someone out there in a Linux newsgroup who is willing to help you get around your problem. Because the source code is available, if you need something fixed you can even patch the code yourself! On the other hand, Ive seen commercial operating system vendors sit on reported problems for months without fixing them. Remember that the culture of Linux is one that thrives on people helping other people.

NOTE: If you have general questions about Red Hat Linux, try the linux. redhat . misc newsgroup. For specific questions about networking or hardware, try the following newsgroups:

comp. os. linux .networking and comp . os. ].inux.hardware, respectively.

What Is Red Hat Linux?

Having directories of software packages floating extraneously around the Internet was not a bad way for hackers to share software. However, for Linux to be acceptable to a less technical population of computer users, it needed to be simple to install and use. Likewise, businesses that were thinking about committing their mission-critical applications to a computer system would want to know that this system had been carefully tested.

To those ends, several companies and organizations began gathering and packaging Linux software together into usable forms called dictributions. The main goal of a Linux distribution

is to make the hundreds of unrelated software packages that make up Linux work together as a cohesive whole. The most popular distribution is Red Hat Linux.

Red Hat Linux is a commercial product produced by Red Hat Software, Inc. You can walk into a store and buy a boxed set of CDs and manuals. Or you can get Red Hat Linux free by downloading it over the Internet or by installing it from CDs that come with books such as this one. The boxed set provides technical support on installation and an extra CD that contains limited and demo versions of commercially available Linux application packages (such as word processors and database applications). Check the Red Hat Web site (www. redhat . corn) for details on what is included with Red Hat products.

Why Choose Red Hat Linux?

To distinguish themselves from other versions of Linux, each distribution adds some extra features. Because many power features included in most Linux distributions come from established open source projects (such as Apache, Samba, KDE, and so on), often enhancements for a particular distribution exist to make it easier to install, configure, and use Linux. Also, because there are different software packages available to do the same jobs (such as window managers or a particular server type), a distribution can distinguish itself by which packages it chooses to include and feature.

Choosing Red Hat Linux as your distribution puts you in good company. Computer companies such as IBM offer Red Hat Linux on their high-end server hardware. High-profile customers such as Amazon.com rely on Red Hat Linux as the primary operating system to support their business. This is the same operating system that you and thousands of others like you can use to run a small business or manage a home network or personal Web server.

Red Hat Linux has set itself apart from other Linux distributions with these features:

Software packaging Red Hat Software, Inc. created the Red Hat Package Management (RPM) method of packaging Linux. RPMs allow less technically savvy users to easily install Linux software. With RPM tools, you can install from CD, hard disk, over your LAN, or over the Internet. Its easy to track which packages are installed or to look at the contents of a package. Because RPM is available to the Linux community, it has become one of the de facto standards for packaging Linux software.

CROSS-REFERENCE: Chapter 5 describes how to install RPM packages.

Easy Installation The Red Hat Linux installation process provides easy steps for installing Linux. During installation, Red Hat also helps you take the first few steps toward configuring Linux. You can choose which packages to install and how to partition your hard disk. You can even get your desktop GUT ready to go by configuring your video card, user accounts, and even your network.

I CROSS-REFERENCE: Chapter 2 covers Red Hat Unux Installation,

UNIX System Vstyle run-level scripts To have your system services (daemon processes) start up and shut down in an organized way, Red Hat Linux uses the UNIX System V mechanism for starting and stopping services. Shell scripts (that are easy to read and change) are contained in subdirectories of /etc. When the run level changes, such as when the system boots up or you change to single-user mode, messages tell you whether each service started correctly or failed to execute properly (a very nice feature!). Chapter 12 describes how to use run-level scripts.

Desktop environments (GNOME and KDE) To make it easier to use Linux, Red Hat Linux comes packaged with GNOME and KDE desktop environments. GNOME is installed by default and offers some nice features that include drag-and-drop protocols and windows that operate like window shades. KDE is another popular desktop manager that includes a wide range of tools tailored for the KDE environment, such as the KDE Control Center for configuring the desktop and the KOrganizer for managing appointments.

GUI Administration tools There are some helpful configuration tools for setting up some of the trickier tasks in Linux. Several different GUT tools provide a graphical,

form-driven interface for configuring networking, users, file systems, and initialization

Les services. Instead of creating obtuse command lines or having to create tricky

configuration files, these graphical tools can set up those files automatically.

r NOTE: There are advantages and disadvantages of using a GUI-based program to manipulate text-based configuration flies. GUI-based configuration tools can lead you through a setup procedure and error-check the information you enter However, some features cant be accessed through the GUI, and if something goes wrong it can be tnckier to debug Also by adding propnetary interfaces to standard features, different Linux versions start to diverge.

Testing The exact configuration that you get on a Red Hat Linux distribution has been thoroughly tested by experts around the world. The simple fact that a software

Led package is included in the Red Hat Linux distribution is an indication that it has achieved a certain level of quality.

Automatic updates The software packages that make up Red Hat Linux are constantly being enhanced and fixed in various ways. To provide a mechanism for the automatic selection, download, and installation of updated software packages, Red Hat created the Red Hat Network. Using the Red Hat Network Web site or the up2date command, you can receive critical security fixes and new features very simply over the Internet.

New Features in Red Hat Linux 8

Although Red Hat continues to build strength and stability into its Linux distribution, Red Hat Linux 8 is strikingly different from earlier versions on its surface. Red Hat is betting that

future Linux administrators will prefer GUI windows over commands and text editors. And Red Hat is hoping that offering similar menus and icons will simplif~ Red Hat Linux for users.

As for major internal changes, Red Hat Linux 8 is built using the GNU C Compiler (gcc) release 3.2. This is a major upgrade from the gcc 2.96 used in Red Hat Linux 7.3. Although gcc release 3.0 has been available since June 2001, it has been considered unstable until the recent 3.2 release. The compiler is the software that turns the source code (instructions that programmers write) into binary code (executable commands that a computers processor runs).

As for changes to packaging, Red Hat Linux 8 is as interesting for what it left out as it is for what it put in. For example:

Netscape Navigator has been dropped, leaving its open-source brother, Mozilla, as the primary Web browser.

New administrative windows that configure X and install RPM packages have replaced Xconfigurator and gnorpm packages, respectively.

Because of licensing issues related to MP3 audio and video formats, packages that included MP3 decoding have been dropped. These include mpg32 1 (audio player), libmad (MPEG audio decoder), smpeg (MPEG audio/video player), and xine (audio/video player).

See Appendix B for information on other packages no longer included in Red Hat Linux.

The following paragraphs describe many of the major features that are in Red Hat Linux 8.

Red Hat config tools

Red Hat has added to their growing arsenal of graphical administrative tools. Since dropping the linuxconf and bypassing the Webmin graphical administrative interfaces, Red Hat has been steadily developing and adding its own administrative tools to its distribution. As a result, a systems administration can often skip running shell commands and editing plain-text configuration files to set up servers, manage system resources, or add users.

The following is a list of Red Hat GUI packages and what each is used to configure:

redhat-config-blnd: Domain Name System server.

redhat-config-date: System time and date.

redhat-config-bttpd: Apache Web server.

redhat-config-language: Languages for Red Hat Linux.

redhat-config-keyboard: Keyboard selection.

redhat-config-klckstart: Kickstart files for unattended Red Hat Linux installations.

redhat-config-mouse: A mouse.

redhat-config-network: Network interfaces.

redhat-conflg-nfs: Network File System shared directories.

redhat-config-packages: Red Hat Linux software.

redhat-config-printer: Printers (Non-GUI)

redhat-config-prlnter-gul: Printers (GUI).

redhat-config-proc: Kernel tunable parameters.

redhat-config-rootpassword: Change your root password.

redhat-conflg-securltylevel: Iptables firewalls.

redhat-config-services: System services. redhat-conflg-soundcard: Sound card.

redhat-contig-users: User accounts.

redbat-conflg-xfree86: X display and monitor.

You can launch the tools associated with the previous packages either from the main Red Hat menu or from a Terminal window. In most cases, the name of the command you run to launch the window is the same name as the package it comes in.

Red Hat desktop interlaces

KDE and GNOME are desktop environments that provide a framework for running and developing graphical applications and offer a full range of preferences to allow users to tailor the exact desktop look and feel. In Red Hat Linux 8, Red Hat seems to have taken them at their word by offering KDE and GNOME desktops in the distribution that have a default Red Hat look and feel that might have some KDE and GNOME die-hards wondering where their old desktops went.

Whether you select KDE or GNOME as your desktop environment, expect to see most of the same menus and icons after you log into Red Hat Linux 8. Under the surface, however, are powerful sets of tools that let you put together your desktop however you like.

The versions of KDE and GNOME that come with Red Hat Linux 8 are KDE 3.0 and GNOME 2.0. Both represent major releases of maturing desktop environments.

KDE3.O

Besides including a full set of configuration tools and software development interfaces, KDE continues to include a large set of user applications (most of which begin with k). Recently, KDE added an office suite (called koffice) and continues to offer a strong group of multimedia sound and video applications. New KDE packages added since Red Hat Linux 7.3 include the following education-oriented packages:

keduca: Tools for taking tests and exams.

kgeo: An interactive KDE geometry package.

klettres: A French alphabet tutor.

kmessedwords: A letter order game.

kstars: A desktop planetarium.

ktouch: A touch typing tutor.

kvoctraln: A vocabulary trainer.

Also featured in KDE 3.0 is new printing environment (KDEPrint), internationalization (50

languages are supported), and powerful enhancements to Konqueror. Konqueror is the KDE

Web browser, file manager, and document viewer. See Chapter 4 for a description of

Konqueror features, as well as other tools available in KDE 3.0.

GNOME 2,0

With version 2.0, GNOME continues to offer a solid application programming framework and improved ease-of-use features. Accessibility features added to GNOME 2.0 include Gnopemicus (screen reader and magnifier for the visually impaired) and GNOME Onscreen Keyboard (keyboard assistant for those who have difficulties with a standard keyboard and mouse). New features in GNOME 2.0 include:

Performance Improvements Implementation improvements help the GNOME desktop perform faster than previous versions, even on older computers.

Ease-of-use features Panels and menus are more flexible, dialog boxes remember file names and allow filename completion, and the search tool offers more search rules to use. Instead of simply adding more applications, GNOME has tried to make the most important features easier to access.

Expanded Nautilus file manager features New Nautilus features let you do such things as open shared files and printers from Windows systems (SMB), store and run

your own scripts, and change a variety of preferences.

I CROSS-REFERENCE: See Chapter 4 for a description of

Apache 2.0

Dont go looking for apache packages anymore, because they wont be there. For Apache 2.0, the name of Apache packages changed from apache to httpd (to reflect the name of the Apache server daemon). Once you have found the package, however, you will find the Apache Web server software you have always known and loved, with some improved features:

Choosing ports and interfaces A new Listen directive replaces BindAddress and Port directives. Now you can now more easily which ports Apache listens to for which

Web addresses configured on your system.

Improved Dynamic Shared Objects DSO support has changed to allow you to simply add LoadModule lines to include the modules you need. You also dont have to

worry about the order of module loading, since Apache makes sure that everything is loaded in the correct order. Names and features of many modules have changed significantly since the previous Apache release.

Indexing Options that affect how directories of Web content are sorted and displayed on your Apache Web server have changed significantly. The Fancylndexing directive is gone but can be used as an option to the IndexOptions directive. A new VersionSort option to IndexOptions helps you sort software package names in ways that more appropriately show the order of package versions than they do with default sorting.

If you are migrating your computer from an Apache 1.3 system, I strongly recommend you refer to the Apache Migration HOWTO. If the Apache (httpd) package is installed, you will find this HOWTO here: /usr/share/doc/httpd*/migration.html.

Installation

A new flrstboot feature was added to Red Hat Linux 8. The first time you reboot Red Hat Linux 8 after you install it, the Red Hat Setup Agent appears. This agent steps you through the initial configuration of date and time, the Red Hat update agent, and additional software CD installations.

I CROSS-REFERENCE: Red Hat Linux installation is described in Chapter 2.

Additional software packages

Red Hat Linux cant go from 600 to nearly 1,500 software packages in a few years time without having lots of new features spread across the operating system. Along with packages already mentioned in this section, the following bullet list should give you an idea of some of the new software packages for Red Hat Linux 8:

dat-spi Adds accessibility features in GNOME.

eog Eye of GNOME image viewer.

fontconflg X font configuration tools.

httpd, httpd-manual Renamed Apache Web server packages.

lpxutils: Utilities for configuring and working with Novell IPX networks.

mdadm Tools to manage software RAID devices.

metacity New default window manager for GNOME.

oprofile System profiling software.

privoxy Web privacy proxy server.

qmkbootdlsk Tool to create a boot disk from the GUI.

rdesktop Used to display a remote NT desktop.

There are other new packages in Red Hat Linux 8 as well. For a more complete list, see Appendix B.

Red Hat Linux 8 Bible Improvements

While a significant amount of effort goes into adding new release features (such as Apache and new Red Hat config tools) to this book, some additions to this edition of the Red Hat Linux Bible were not tied to new features. They were just part of the continuing development of this book. The following sections are new to this edition of the book:

KDE and GNOME Procedures I reworked Chapter 4, not only to include new KDE and GNOME desktop features but to focus on some of the neat new features for using and configuring your desktop. For example, I describe how to create image galleries using Konqueror and how to use Nautilus to display Windows shared files and printers.

Configuring Install Servers I improved the part on creating install servers (Chapter 2) to include how to copy and set up disk images for NFS and hard disk installs.

Finding Windows-Equivalent Applications In Chapter 5,1 have started a list of Windows applications that you may be relying on today and named applications that run in Red Hat Linux that you can use to replace those applications. (I expect to continue expanding the list in future editions.)

Using 5511 to run remote X applications As a more secure and, in fact, simpler way of running remote X applications so they appear on your local screen, I have added this

short procedure to Chapter 5.

Getting Mall from the Server (POP) I added a simple, but important, procedure to Chapter 19 for running a Post Office Protocol server. The section tells how to start up

the POP server so users of your mail server can download mail to their desktop systems.

Configuring a VPN I added a section on how to configure Crypto IP Encapsulation (CIPE) to create a virtual private network connection.

Besides these new sections, procedures throughout the book have been tested and corrected to match changes that have occurred within existing Red Hat Linux software.

The Culture of Free Software

I would be remiss to not say something about the culture of free software development from which Linux has thrived and will continue to thrive. The copyright for Red Hat Linux is covered under the GNU public license. That license, which most free software fails under, provides the following:

Author rights The original author retains the rights to his or her software.

Free distribution People can use the GNU software in their own software, changing and redistributing it as they please. They do, however, have to include the source code with their distribution (or make it easily available).

Copyright maintained Even if you were to repackage and resell the software, the original GNU agreement must be maintained with the software. This means that all future recipients of the software must have the opportunity to change the source code, just as you did.

It is important to remember that there is no warranty on GNU software. If something goes wrong, the original developer of the software has no obligation to fix the problem. However, the Linux culture has provided resources for that event. Experts on the Internet can help you iron out your problems, or you can access one of the many Linux newsgroups to read how others have dealt with their problems and to post your own questions about how to fix yours. Chances are that someone will know what to do maybe even going so far as to provide the software or configuration file you need.

NOTE: The GNU project uses the term free softwaieto describe the software that is covered by the GNU license. On occasion, you may see the term open-source sof/ware being used to describe software. Though source code availability is part of the GNU license, the GNU project claims that software defined as open source is not the same as free software because it can encompass semi-free programs and even some ~roonetarv oroarams. ~ee www. onensource - ora br a aescriDtion of ooen-source software.

Summary

Linux is a free computer operating system that was created by Linus Torvalds in 1991 and that has grown from contributions from software developers all over the world. Red Hat Linux is a distribution of Linux that packages together the software needed to run Linux and makes it easier to install and run.

Features in Red Hat Linux include a simplified installation procedure, Red Hat Package Management (RPM) tools for managing the software, and easy-to-use GNOME and KDE desktop environments. You can get Red Hat Linux from the Internet, from distributions that come with books such as this one, or from a commercially available boxed set of Red Hat Linux software.

Linux is based on a culture of free exchange of software. Linuxs roots are based in the UNIX operating system. UNIX provided most of the framework that was used to create Linux. That framework came in the form of the POSIX standard, which defined the interfaces a UNIX system needs to support in order to be a TJNTX system.