Cover | Table of Contents

Table of Contents

Chapter 1: Introduction to Linux

Content preview·Buy reprint rights for this chapter

Welcome to Running Linux, Version 5! When we wrote the first edition of this book, Linux had barely arrived on the scene. Our task seemed simple: help readers learn the basics of a new operating system that required a pretty fixed and predictable set of tasks. Few if any observers expected Linux would become a best-of-breed operating system, supported by the vast majority of hardware and software manufacturers on the planet. Who would have known that Linux would grow from a small user base of 30,000 people in 1995 to hundreds of millions only 10 years later? People use Linux everywhere on the planet and in some cases in outer space and under the ocean.

To the casual observer, Linux looks like a fairly simple personal computer desktop built on the same chassis as any IBM PC. People use Linux to browse the Internet, exchange email, listen to music, watch videos, and instant message their friends and coworkers. Students and office workers create documents with word processors, perform numerous tasks with spreadsheet programs, and make slide presentations.

The same Linux operating system also drives sonar arrays in nuclear submarines, indexes every document on the Internet, unifies large corporate data centers, runs nearly 70% of all web sites in the world, records your television programs, works in your cellular phone, and runs the switches that allow you to connect with your friends and family anywhere on the globe. Linux runs systems on the international space station as well as the shuttles that take astronauts there. It protects you from spam and computer viruses on numerous routers and back-end systems.

You can benefit directly from installing Linux on a system at home, at school, or in the office, and having all that power at your fingertips. Not only can you carry on everyday surfing and office work, but you can also learn how to write database queries, administer a web server, filter mail for spam and viruses, automate your environment through scripting languages, access web services, and participate in the myriad of other cutting-edge activities provided by modern computing.

Additional content appearing in this section has been removed.
Purchase this book now or read it online at Safari to get the whole thing!

About This Book

Content preview·Buy reprint rights for this chapter

This book provides an overview and guide to Linux as a desktop and a back-office system. We present information on topics to satisfy novices and wizards alike. This book should provide sufficient material for almost anyone to choose the type of installation they want and get the most out of it. Instead of covering many of the volatile technical details—those things that tend to change with Linux's rapid development—we give you the information that helps you over the bumps as you take your first steps with popular distributions, as well as background you will need if you plan to go onto more advanced Linux topics such as web services, federated identity management, high-performance computing, and so on.

We geared this book for those people who want to understand the power that Linux can provide. Rather than provide minimal information, we help you see how the different parts of the Linux system work, so you can customize, configure, and troubleshoot the system on your own. Linux is not difficult to install and use. Many people consider it easier and faster to set up than Microsoft Windows. However, as with any commercial operating system, some black magic exists, and you will find this book useful if you plan to go beyond desktop Linux and use web services or network management services.

In this book, we cover the following topics:

• The design and philosophy of the Linux operating system, and what it can do for you.
• Information on what you need to run Linux, including suggestions on hardware platforms and how to configure the operating system depending on its specified role (e.g., desktop, web server, database and/or application server).
• How to obtain and install Linux. We cover the Red Hat, SUSE, and Debian distributions in more detail than others, but the information is useful in understanding just about any distribution.
• An introduction, for new users, to the original Linux/Unix system philosophy, including the most important commands and concepts still in use.
• Personal productivity through slick and powerful office suites, image manipulation, and financial accounting.

Additional content appearing in this section has been removed.
Purchase this book now or read it online at Safari to get the whole thing!

Who's Using Linux?

Content preview·Buy reprint rights for this chapter

Application developers, system administrators, network providers, kernel hackers, students, and multimedia authors are just a few of the categories of people who find that Linux has a particular charm.

Programmers are increasingly using Linux because of its extensibility and low cost—they can pick up a complete programming environment for free and run it on inexpensive PC hardware—and because Linux offers a great development platform for portable programs. In addition to the original FSF tools, Linux can utilize a number of development environments that have surfaced over the last three years, such as Eclipse (http://eclipse.org). Eclipse is quite a phenomenon: a tribute to both the creativity of the open source community and the fertility of a collaboration between an open source community and a major vendor (Eclipse was originally developed and released by IBM). It is an open source community focused on providing an extensible development platform and application frameworks for building software.

Eclipse's tools and frameworks span the software development life cycle, including support for modeling; language development environments for Java?, C/C++, and other languages; testing and performance; business intelligence; rich client applications; and embedded development. A large, vibrant ecosystem of major technology vendors, innovative startups, universities, and research institutions and individuals extend, complement, and support the Eclipse platform.

Networking is one of Linux's strengths. Linux has been adopted by people who run large networks because of its simplicity of management, performance, and low cost. Many Internet sites make use of Linux to drive large web servers, e-commerce applications, search engines, and more. Linux is easy to merge into a corporate or academic network because it supports common networking standards. These include both old stand-bys, such as the Network File System (NFS) and Network Information Service (NIS), and more prominent systems used in modern businesses, such as Microsoft file sharing (CIFS and related protocols) and Lightweight Directory Access Protocol (LDAP). Linux makes it easy to share files, support remote logins, and run applications on other systems. A software suite called Samba allows a Linux machine to act as a Windows server in Active Directory environments. The combination of Linux and Samba for this purpose is faster (and less expensive) than running Windows Server 2003. In fact, given the ease with which Linux supports common networking activities—DHCP, the Domain Name System, Kerberos security, routing—it's hard to imagine a corporate networking task for which it's unsuited.

Additional content appearing in this section has been removed.
Purchase this book now or read it online at Safari to get the whole thing!

System Features

Content preview·Buy reprint rights for this chapter

Linux has surpassed the features found in implementations of Unix and Windows. With the changes offered by IBM's Power Architecture, for example, Linux provides functionality for commodity hardware normally only found on the most expensive mainframes. Additionally, the latest kernels include the structure of Security Enhanced Linux (SELinux) provided by the National Security Agency (http://www.nsa.gov/selinux). SELinux provides the most trusted computing environment available today.

Now add Linux's ability to provide virtualization at the kernel level. Through Xen (http://sourceforge.net/projects/xen), Linux can securely execute multiple virtual machines, each running its own operating system, on a single physical system. This allows enterprises to stop server sprawl and increase CPU utilization.

This section provides a nickel tour of Linux features.

Linux is a complete multitasking , multiuser operating system (as are all other versions of Unix). This means that many users can be logged onto the same machine at once, running multiple programs simultaneously. Linux also supports multiprocessor systems (such as dual-Pentium motherboards), with support for up to 32 processors in a system, which is great for high-performance servers and scientific applications.

The Linux system is mostly compatible with a number of Unix standards (inasmuch as Unix has standards) on the source level, including IEEE POSIX.1, System V, and BSD features. Linux was developed with source portability in mind: therefore, you will probably find features in the Linux system that are shared across multiple Unix implementations. A great deal of free Unix software available on the Internet and elsewhere compiles on Linux out of the box.

If you have some Unix background, you may be interested in some other specific internal features of Linux, including POSIX job control (used by shells such as the C shell, csh, and bash), pseudoterminals (pty devices), and support for national or customized keyboards using dynamically loadable keyboard drivers. Linux also supports virtual consoles , which allow you to switch between multiple login sessions from the system console in text mode. Users of the

Additional content appearing in this section has been removed.
Purchase this book now or read it online at Safari to get the whole thing!

About Linux's Copyright

Content preview·Buy reprint rights for this chapter

Linux is covered by what is known as the GNU GPL. The GPL, which is sometimes referred to as a "copyleft" license, was developed for the GNU project by the Free Software Foundation. It makes a number of provisions for the distribution and modification of "free software." "Free," in this sense, refers to freedom, not just cost. The GPL has always been subject to misinterpretation, and we hope that this summary will help you to understand the extent and goals of the GPL and its effect on Linux. A complete copy of the GPL is available at http://www.gnu.org/copyleft/gpl.html.

Originally, Linus Torvalds released Linux under a license more restrictive than the GPL, which allowed the software to be freely distributed and modified, but prevented any money changing hands for its distribution and use. The GPL allows people to sell and make profit from free software, but doesn't allow them to restrict the right for others to distribute the software in any way.

First, we should explain that "free software" covered by the GPL is not in the public domain. Public domain software is software that is not copyrighted and is literally owned by the public. Software covered by the GPL, on the other hand, is copyrighted to the author or authors. This means that the software is protected by standard international copyright laws and that the author of the software is legally defined. Just because the software may be freely distributed doesn't mean it is in the public domain.

GPL-licensed software is also not "shareware ." Generally, shareware software is owned and copyrighted by the author, but the author requires users to send in money for its use after distribution. On the other hand, software covered by the GPL may be distributed and used free of charge.

The GPL also allows people to take and modify free software, and distribute their own versions of the software. However, any derived works from GPL software must also be covered by the GPL. In other words, a company could not take Linux, modify it, and sell it under a restrictive license. If any software is derived from Linux, that software must be covered by the

Additional content appearing in this section has been removed.
Purchase this book now or read it online at Safari to get the whole thing!

Open Source and the Philosophy of Linux

Content preview·Buy reprint rights for this chapter

When new users encounter Linux, they often have a few misconceptions and false expectations of the system. Linux is a unique operating system, and it's important to understand its philosophy and design in order to use it effectively. At the center of the Linux philosophy is a concept that we now call open source software.

Open source is a term that applies to software for which the source code—the inner workings of the program—is freely available for anyone to download, modify, and redistribute. Software covered under the GNU GPL, described in the previous section, fits into the category of open source. Not surprisingly, though, so does software that uses copyright licenses that are similar, but not identical, to the GPL. For example, software that can be freely modified but that does not have the same strict requirements for redistribution as the GPL is also considered open source. Various licenses fit this category, including the BSD License and the Apache Software License .

The so-called open source and free software development models started with the Free Software Foundation and were popularized with Linux. They represent a totally different way of producing software that opens up every aspect of development, debugging, testing, and study to anyone with enough interest in doing so. Rather than relying upon a single corporation to develop and maintain a piece of software, open source allows the code to evolve, openly, in a community of developers and users who are motivated by a desire to create good software, rather than simply to make a profit.

O'Reilly has published two books, Open Sources 1.0 and Open Sources 2.0, that serve as good introductions to the open source development model. They're collections of essays about the open source process by leading developers (including Linus Torvalds and Richard Stallman). Another popular text on this topic—so often cited that it is considered nearly canonical—is The Cathedral and the Bazaar, by Eric S. Raymond.

Open source has received a lot of media attention, and some are calling the phenomenon the next wave in software development, which will sweep the old way of doing things under the carpet. It still remains to be seen whether that will happen, but there have been some encouraging events that make this outcome seem likely. For example, Netscape Corporation has released the code for its web browser as an open source project called Mozilla, and companies such as Sun Microsystems, IBM, and Apple have released certain products as open source in the hopes that they will flourish in a community-driven software development effort.

Additional content appearing in this section has been removed.
Purchase this book now or read it online at Safari to get the whole thing!

Sources of Linux Information

Content preview·Buy reprint rights for this chapter

As you have probably guessed, many sources of information about Linux are available, apart from this book.

If you have access to the Internet, you can get many Linux documents via web and anonymous FTP sites all over the world. If you do not have direct Internet access, these documents may still be available to you; many Linux distributions on CD-ROM contain all the documents mentioned here and are often available off the retail shelf.

A great number of web and FTP archive sites carry Linux software and related documents. Appendix A contains a listing of some of the Linux documents available via the Internet.

Examples of available online documents are the Linux FAQ, a collection of frequently asked questions about Linux; the Linux HOWTO documents, each describing a specific aspect of the system—including the Installation HOWTO, the Printing HOWTO, and the Ethernet HOWTO; and the Linux META-FAQ, a list of other sources of Linux information on the Internet.

Additional documentation , individually hosted "HOWTOs," blogs, knowledge bases, and forums exist that provide significant material to help individuals use Linux. Distributors maintain diverse mailing lists and forums dealing with a variety of subjects from using Linux on a laptop to configuring web servers. Such web sites and digests of mailing lists have largely taken over for Linux-related Usenet newsgroups; see "Usenet Newsgroups" later in this chapter.

The central Linux Documentation home page is available to web users at http://www.tldp.org. This page contains many HOWTOs and other documents, as well as pointers to other sites of interest to Linux users, including the Linux Documentation Project manuals (see the following section).

There are a number of published works specifically about Linux. In addition, a number of free books are distributed on the Internet by the Linux Documentation Project (LDP), a project carried out over the Internet to write and distribute a bona fide set of "manuals" for Linux. These manuals are analogs to the documentation sets available with commercial versions of Unix: they cover everything from installing Linux to using and running the system, programming, networking, kernel development, and more.

Additional content appearing in this section has been removed.
Purchase this book now or read it online at Safari to get the whole thing!

Getting Help

Content preview·Buy reprint rights for this chapter

First, we should mention that Linux has a rich community of volunteers and participants who need help and offer help for free. A good example of such a community is Ubuntu (http://www.ubuntulinux.org). Supported by a commercial company, Canonical Ltd., that offers low-cost professional support, Ubuntu has a large and enthusiastic community ready to provide old-style Linux support. Ubuntu, a derivative of Debian, employs a number of paid developers who also help maintain the Debian project.

Distributions such as Red Hat, Novell's SUSE, and Mandriva have become quite adept at providing commercial support for their own distributions of Linux and for other open source projects. Following a concept originated by Bernard Golden called the Open Source Maturity Model, Linux companies have done an excellent job in demonstrating their ability to compete using the open source paradigm. They have demonstated the ability to provide:

• Adequate support and maintenance
• Continued innovation
• Product road maps and commitments to adhere to them
• Functionality and ease of use for IT managers, particularly across enterprise-size environments
• Stable business models to fund new development and expand into new product areas
• Structured and scalable partner ecosystems devoted to enabling customer success

Additionally, these Linux companies have established community projects to keep them from becoming stale.

Mature Linux companies also provide extended business offerings, including training, professional sales and support (24 × 7 × 365), indemnification, and quality documentation.

In addition to the companies already mentioned, you will find a channel full of their business partners who have considerable expertise in providing commercial Linux support. Their web sites contain ways to find a business partner that can assist Linux users in a variety of ways.

As you become more accustomed to running Linux, you will probably discover many facets that may pleasantly surprise you. Many people not only use Linux but consider the community their home base. Good luck in the coming days.

Additional content appearing in this section has been removed.
Purchase this book now or read it online at Safari to get the whole thing!

Chapter 2: Preinstallation and Installation

Content preview·Buy reprint rights for this chapter

This chapter represents your first step in installing Linux. We describe how to obtain the Linux software, in the form of one of the various prepackaged distributions , and how to prepare your system. We include ways to partition disks so that Linux can coexist with Windows or another operating system.

As we have mentioned, there is no single "official" distribution of the Linux software; there are, in fact, many distributions, each serving a particular purpose and set of goals. These distributions are available via anonymous FTP from the Internet and via mail on CD-ROM and DVD, as well as in retail stores.

Because Linux is free software, no single organization or entity is responsible for releasing and distributing the software. Therefore, anyone is free to put together and distribute the Linux software, as long as the restrictions in the GPL (and other licenses that may be used) are observed. The upshot of this is that there are many distributions of Linux, available via anonymous FTP or mail order.

You are now faced with the task of deciding on a particular distribution of Linux that suits your needs. Not all distributions are alike. Many of them come with just about all the software you'd need to run a complete system—and then some. Other Linux distributions are "small" distributions intended for users without copious amounts of disk space.

You might also want to consider that distributions have different target groups. Some are meant more for businesses, others more for the home user. Some put more emphasis on server use, others on desktop use.

How can you decide among all these distributions? If you have access to Usenet news, or another computer conferencing system such as web-based discussion boards, you might want to ask there for opinions from people who have installed Linux. Even better, if you know someone who has installed Linux, ask him for help and advice. In actuality, most of the popular Linux distributions contain roughly the same set of software, so the distribution you select is more or less arbitrary.

A particularly interesting type of distribution is the so-called live CD, such as Knoppix (

Additional content appearing in this section has been removed.
Purchase this book now or read it online at Safari to get the whole thing!

Distributions of Linux

Content preview·Buy reprint rights for this chapter

Because Linux is free software, no single organization or entity is responsible for releasing and distributing the software. Therefore, anyone is free to put together and distribute the Linux software, as long as the restrictions in the GPL (and other licenses that may be used) are observed. The upshot of this is that there are many distributions of Linux, available via anonymous FTP or mail order.

You are now faced with the task of deciding on a particular distribution of Linux that suits your needs. Not all distributions are alike. Many of them come with just about all the software you'd need to run a complete system—and then some. Other Linux distributions are "small" distributions intended for users without copious amounts of disk space.

You might also want to consider that distributions have different target groups. Some are meant more for businesses, others more for the home user. Some put more emphasis on server use, others on desktop use.

How can you decide among all these distributions? If you have access to Usenet news, or another computer conferencing system such as web-based discussion boards, you might want to ask there for opinions from people who have installed Linux. Even better, if you know someone who has installed Linux, ask him for help and advice. In actuality, most of the popular Linux distributions contain roughly the same set of software, so the distribution you select is more or less arbitrary.

A particularly interesting type of distribution is the so-called live CD, such as Knoppix (http://www.knoppix.org). These distributions boot from CD and do not require any installation at all; they keep all information in RAM, but can still access your hard drive and other hardware. Besides being a very convenient way of test-driving Linux without having to wipe out anything else, they are also a very good way of rescuing a system that has become unbootable. More about salvaging booting problems will follow later in this book.

If you don't have high-speed Internet access, you can get many Linux distributions via mail order on CD-ROM or DVD. Many distributors accept credit cards as well as international orders, so no matter where you live, you should be able to obtain Linux in this way.

Additional content appearing in this section has been removed.
Purchase this book now or read it online at Safari to get the whole thing!

Preparing to Install Linux

Content preview·Buy reprint rights for this chapter

After you have obtained a distribution of Linux, you're ready to prepare your system for installation. This takes a certain degree of planning, especially if you're already running other operating systems. In the following sections, we describe how to plan for the Linux installation.

Although each release of Linux is different, in general the method used to install the software is as follows:

1. Repartition your hard drive(s). If you have other operating systems already installed, you will need to repartition the drives in order to allocate space for Linux. This is discussed in "Repartitioning Concepts" later in this chapter. In some distributions (such as SUSE), this step is integrated into the installation procedure. Check the documentation of your distribution to see whether this is the case. Still, it won't hurt you to follow the steps given here and repartition your hard drive in advance.
2. Boot the Linux installation medium. Each distribution of Linux has some kind of installation medium—usually a boot floppy or a bootable CD-ROM--that is used to install the software. Booting this medium will either present you with some kind of installation program, which will step you through the Linux installation, or allow you to install the software by hand.
3. Create Linux partitions. After repartitioning to allocate space for Linux, you create Linux partitions on that empty space. This is accomplished with the Linux fdisk program, covered in "Editing /etc/fstab," or with some other distribution-specific program, such as the Disk Druid, which comes with Red Hat Linux.
4. Create filesystems and swap space. At this point, you will create one or more filesystems, used to store files, on the newly created partitions. In addition, if you plan to use swap space (which you should, unless you have really huge amounts of physical memory, or RAM), you will create the swap space on one of your Linux partitions. This is covered in the sections "Creating Swap Space" and "Editing /etc/fstab."
5. Install the software on the new filesystems. Finally, you will install the Linux software on your newly created filesystems. After this, if all goes well, it's smooth sailing. This is covered in "Installing the Software." Later, in "Running into Trouble," we describe what to do if anything goes wrong.

Additional content appearing in this section has been removed.
Purchase this book now or read it online at Safari to get the whole thing!

Post-Installation Procedures

Content preview·Buy reprint rights for this chapter

After you have completed installing the Linux software, you should be able to reboot the system, log in as root, and begin exploring the system. (Each distribution has a different method for doing this; follow the instructions given by the distribution.)

Before you strike out on your own, however, there are some tasks you should do now that may save you a lot of grief later. Some of these tasks are trivial if you have the right hardware and Linux distribution; others may involve a little research on your part, and you may decide to postpone them.

In order to start using your system, you need to create a user account for yourself. Eventually, if you plan to have other users on your system, you'll create user accounts for them as well. But before you begin to explore you need at least one account.

Why is this? Every Linux system has several preinstalled accounts, such as root. The root account, however, is intended exclusively for administrative purposes. As root you have all kinds of privileges and can access all files on your system.

However, using root can be dangerous, especially if you're new to Linux. Because there are no restrictions on what root can do, it's all too easy to mistype a command, inadvertently delete files, damage your filesystem, and so on. You should log in as root only when you need to perform system administration tasks, such as fixing configuration files, installing new software, and so on. See "Maintaining the System" in Chapter 10 for details.

For normal usage, you should create a standard user account. Unix systems have built-in security that prevents users from deleting other users' files and corrupting important resources, such as system configuration files. As a regular user, you'll be protecting yourself from your own mistakes. This is especially true for users who don't have Unix system administration experience.

Many Linux distributions provide tools for creating new accounts. These programs are usually called useradd or adduser. As root, invoking one of these commands should present you with a usage summary for the command, and creating a new account should be fairly self-explanatory.

Additional content appearing in this section has been removed.
Purchase this book now or read it online at Safari to get the whole thing!

Running into Trouble

Content preview·Buy reprint rights for this chapter

Almost everyone runs into some kind of snag or hang-up when attempting to install Linux the first time. Most of the time, the problem is caused by a simple misunderstanding. Sometimes, however, it can be something more serious, such as an oversight by one of the developers or a bug.

This section describes some of the most common installation problems and how to solve them. It also describes unexpected error messages that can pop up during installations that appear to be successful.

In general, the proper boot sequence is as follows:

1. After booting from the LILO prompt, the system must load the kernel image from floppy. This may take several seconds; you know things are going well if the floppy drive light is still on.
2. While the kernel boots, SCSI devices must be probed for. If you have no SCSI devices installed, the system will hang for up to 15 seconds while the SCSI probe continues; this usually occurs after the line:

       lp_init: lp1 exists (0), using polling driver
   

   appears on your screen.
3. After the kernel is finished booting, control is transferred to the system bootup files on the floppy. Finally, you will be presented with a login prompt (either a graphical or a textual one) or be dropped into an installation program. If you are presented with a login prompt such as:

       Linux login:
   

   you should then log in (usually as root or install--this varies with each distribution). After you enter the username, the system may pause for 20 seconds or more while the installation program or shell is being loaded from floppy. Again, the floppy drive light should be on. Don't assume the system is hung.

When attempting to boot the installation medium for the first time, you may encounter a number of problems. Note that the following problems are not related to booting your newly installed Linux system. See "Problems After Installing Linux," later in this chapter, for information on these kinds of pitfalls.

A floppy or medium error occurs when attempting to boot

The most popular cause for this kind of problem is a corrupt boot floppy. Either the floppy is physically damaged, in which case you should re-create the disk with a brand-new floppy, or the data on the floppy is bad, in which case you should verify that you downloaded and transferred the data to the floppy correctly. In many cases, simply re-creating the boot floppy will solve your problems. Retrace your steps and try again.

Additional content appearing in this section has been removed.
Purchase this book now or read it online at Safari to get the whole thing!

Chapter 3: Desktop Environments

Content preview·Buy reprint rights for this chapter

If you installed one of the popular Linux distributions, it came up with a rather attractive graphical interface. This chapter tells you how to use this interface to get work done more quickly and pleasantly. Most Linux systems with graphical interfaces offer a comprehensive graphical environment called a desktop.

This chapter covers both of the popular Linux desktops, the K Desktop Environment (KDE) and GNOME. Readers who have trouble getting their graphical interfaces to work at all, or who want to delve deeper into the guts of Linux graphics, can find help in Chapter 16.

If you plan to run your Linux machine as a server, there is no need to install any of the packages described in this chapter (unless you want to use graphical administration tools). X and the desktop systems require significant memory, CPU time, and disk space, and if your system never has a monitor attached to it, installing them is a waste of time and resources. Similarly, if you will just be doing programming and have no interest in viewing results graphically or using graphical integrated development environments (IDEs), you could well get by without these conveniences.

But for all other systems, KDE and GNOME make Linux appropriate for mass use. They do the kinds of things the average user expects his computer to do for him, such as the following:

• Display many different kinds of content automatically when their icons are clicked, without the user having to specify the program used for display
• Cut and paste both text and pictures from one window to another, even when these windows run different applications that store data in different formats
• Save and restore sessions, so the user can log back in and pick up as much as possible just where she left off
• Aid the user with hints as to where he is, such as thumbnail images and tool tips
• Offer a wealth of beautiful backgrounds, screen savers, and themes
• Allow a dizzying extent of customization—but in a subtle way that allows most users to feel happy with defaults

To offer all these features, both KDE and GNOME require hefty computing power and memory. Modern hardware can handle them comfortably (and they're both getting trimmer over time), but some users prefer to use more lightweight graphical systems that lack some of the power. If you want something partway between a plain command-line console and the resource-intensive environments of KDE or GNOME, try the xfce window manager. It comes with many distributions and can be downloaded from

Additional content appearing in this section has been removed.
Purchase this book now or read it online at Safari to get the whole thing!

Why Use a Graphical Desktop?

Content preview·Buy reprint rights for this chapter

If you plan to run your Linux machine as a server, there is no need to install any of the packages described in this chapter (unless you want to use graphical administration tools). X and the desktop systems require significant memory, CPU time, and disk space, and if your system never has a monitor attached to it, installing them is a waste of time and resources. Similarly, if you will just be doing programming and have no interest in viewing results graphically or using graphical integrated development environments (IDEs), you could well get by without these conveniences.

But for all other systems, KDE and GNOME make Linux appropriate for mass use. They do the kinds of things the average user expects his computer to do for him, such as the following:

• Display many different kinds of content automatically when their icons are clicked, without the user having to specify the program used for display
• Cut and paste both text and pictures from one window to another, even when these windows run different applications that store data in different formats
• Save and restore sessions, so the user can log back in and pick up as much as possible just where she left off
• Aid the user with hints as to where he is, such as thumbnail images and tool tips
• Offer a wealth of beautiful backgrounds, screen savers, and themes
• Allow a dizzying extent of customization—but in a subtle way that allows most users to feel happy with defaults

To offer all these features, both KDE and GNOME require hefty computing power and memory. Modern hardware can handle them comfortably (and they're both getting trimmer over time), but some users prefer to use more lightweight graphical systems that lack some of the power. If you want something partway between a plain command-line console and the resource-intensive environments of KDE or GNOME, try the xfce window manager. It comes with many distributions and can be downloaded from http://www.xfce.org, along with its documentation. With a much smaller footprint than KDE or GNOME, it offers a surprisingly rich range of features.

Because KDE and GNOME were designed to be intuitive and borrowed many ideas from other popular graphical environments, their basic use is intuitive for most computer users. In this chapter we'll explore some of the neat things that they and their key applications offer, but which you might not have found out through everyday experimentation.

Additional content appearing in this section has been removed.
Purchase this book now or read it online at Safari to get the whole thing!

The K Desktop Environment

Content preview·Buy reprint rights for this chapter

KDE is an open source software project that aims at providing a consistent, user-friendly, contemporary desktop for Unix, and hence, Linux systems. Since its inception in October 1996, it has made great progress. This is partly due to the choice of a very high-quality GUI toolkit, Qt, as well as the consequent choice of using C++ and its object-oriented features for the implementation.

KDE employs a component technology called KParts that makes it possible to embed one application into another transparently, such that, for example, the web browser Konqueror can display PDF documents in its own browser window by means of the PDF display program KPDF , without Konqueror having to have a PDF display component of its own. The same goes for the KOffice suite (see http://koffice.kde.org), discussed in Chapter 8, where, for example, the word processor KWord can embed tables from the spreadsheet application KSpread seamlessly.

KDE is in ever-continuing development, but every few months the KDE team puts out a so-called official release that is considered very stable and suitable for end users. The KDE team makes these available in source form, and most distributions provide easy-to-install binary packages within days of a source release. If you don't mind fiddling around with KDE and can stand an occasional bug, you can also live on the bleeding edge and download daily snapshots of KDE, but this is not for the fainthearted. At the time of this writing, the current stable release was 3.4.2. To stay current with KDE development, visit http://www.kde.org, the official web site of the KDE project, often.

One of the goals of the KDE team is to make everything in KDE configurable by GUI dialogs. Underneath the configuration system lies a set of text files in a fairly simple parameter=value format; you can edit these if you prefer, but you never need to. Even the most experienced users usually admit that in order to do simple things, such as change the background color of the desktop, it's faster to click a few buttons than to read the manual page, find the syntax for specifying the background color, open the configuration file, edit it, and restart the window manager.

Additional content appearing in this section has been removed.
Purchase this book now or read it online at Safari to get the whole thing!

KDE Applications

Content preview·Buy reprint rights for this chapter

Thousands of programs are available for KDE. They range from basic utilities (such as konsole, the terminal emulator, and OClock, a rudimentary clock) to editors, programming aids, games, and multimedia applications . The most we can provide here is a tiny slice of the software available for KDE. In this section, we'll present those applications that all KDE users should know how to use. These aren't necessarily the most exciting programs out there, but they should certainly be part of your toolbox.

There are many, many more KDE applications than the few we can list here. You will make the acquaintance of some of them, such as KWord, the word processor, and Kontact, the personal information manager and mail user agent (and much else), elsewhere in this book. But others haven't found space in this book, so you should search through your favorite Linux archive for more exciting KDE programs; there are thousands of them to discover.

Also remember that if there really is no KDE program for a task you have to solve, you can always resort to one of the classic X applications, if available. These do not look as nice and integrate as well, but they still work on a KDE desktop.

Let's start our exploration of X applications with the workhorse that you might be spending a lot of your time with in the terminal. This is simply a window that contains a Unix shell. It displays a prompt, accepts commands, and scrolls like a terminal.

Traditionally, xterm was the classic Unix terminal emulator. It has been superseded by konsole in the KDE desktop environment.

Perhaps you are struck by the irony of buying a high-resolution color monitor, installing many megabytes of graphics software, and then being confronted by an emulation of an old VT100 terminal. But Linux is much more than a point-and-click operating system. There are plenty of nice graphical applications, but a lot of the time you'll want to do administrative tasks, and a command-line interface still offers the most powerful tool for doing that. You'll get a glimpse of these tasks in Chapter 4.

So let's take look at a konsole

Additional content appearing in this section has been removed.
Purchase this book now or read it online at Safari to get the whole thing!

The GNOME Desktop Environment

Content preview·Buy reprint rights for this chapter

The GNOME desktop environment, like KDE, is a complete desktop suite, from the desktop background up to a set of applications. As with KDE, GNOME can run any X application, and both KDE and GNOME rely on standards set by the Freedesktop.org group. In fact, the distinction between the two desktops is, in many ways, of interest more to developers choosing toolkits than to users, who in most cases mix and match applications without having to worry about the underpinnings.

The primary goals of the GNOME project are simplicity and ease of use. Applications must comply with extensive human interface guidelines to become part of the official GNOME desktop. Because GNOME makes an excellent platform for development in C, C++, Python, Java, and C#, unofficial and third-party applications are numerous. In some cases (notably the XML system), GNOME libraries appear in command-line and server-based applications.

Of course, for our purposes, the interesting parts are the core desktop and its associated applications. In the following sections, we go over the GNOME look and feel, talk a little bit about the customization options it offers to you, and then give a quick tour of major applications, such as Evolution and Nautilus.

Most Linux distributions include GNOME, but if you haven't installed it yourself, or if you want a newer version, you can visit http://gnome.org or your distribution's web page for downloads.

The GNOME desktop is designed to be familiar to anyone who has used a computer before. Although you can change the settings in almost any way, a typical installation will have a desktop with icons on it and a panel along the top and bottom. The panels are among the most important GNOME tools because they are so versatile and they allow a wide range of interactions with your system. Panels can exist along one edge of your screen, like the Windows control panel; along a portion of it, like the Macintosh Dock, and more. They can contain buttons to launch applications and small applications called applets such as clocks, system monitors, and even tiny games.

Section 3.4.1.1: Basic GNOME tasks

Additional content appearing in this section has been removed.
Purchase this book now or read it online at Safari to get the whole thing!

GNOME Applications

Content preview·Buy reprint rights for this chapter

Now that you have a feel for the desktop and how to get around it, let's take a look at some of the applications that are built to go with it. Note that these applications aren't restricted to the GNOME desktop, and they aren't the only applications you can run on the GNOME desktop—they're just built from the same materials and work particularly well together.

Evolution is what's known as a groupware suite; it combines email with a calendar and an address book so that communication and scheduling tasks all fall into one convenient package. We don't have room to go into depth regarding all three, but a complete manual is included in the Help menu and is available online at http://gnome.org/projects/evolution.

You can start Evolution by selecting Evolution from your Applications menu, or by typing evolution at the command line. A screen like the one in Figure 3-7 should come up.

Figure 3-7: Evolution on the GNOME desktop

The first time you run Evolution, you'll be asked to create an email account by entering information about yourself and your email access. You can copy this information from your existing mail program, or ask your system administrator or ISP.

Evolution works with standard mail server protocols and can be used in almost any network environment. It lets you leave your mail on the server (if it's running the IMAP protocol), download mail to your local system (if it runs either the IMAP or the POP protocol), or use mail spools on your local system (if you're running your own mail server). In addition, Evolution supports Microsoft Exchange 2000 and later and Novell GroupWise 6.5 and later for mail, calendar, and address functions.

Once you've created an account, you will be presented with the main Evolution window. On the left side of the Evolution window is a shortcut bar, with a list of available tools at the bottom and a list of available sources of data at the top. Click the buttons at the bottom to switch among email, calendar, task list, contacts, and Microsoft Exchange tools.

The following sections describe Evolution's major features.

Additional content appearing in this section has been removed.
Purchase this book now or read it online at Safari to get the whole thing!

Chapter 4: Basic Unix Commands and Concepts

Content preview·Buy reprint rights for this chapter

If you've come to Linux from Windows or another non-Unix operating system, you have a steep learning curve ahead of you. We might as well be candid on this point. Unix is a world all its own, even though it has become a lot more user-friendly over the last few years.

In this chapter, we introduce the rudiments of Unix for those readers who have never had exposure to this operating system. If you are coming from Microsoft Windows or other environments, the information in this chapter will be absolutely vital to you. Unlike other operating systems, Unix is not at all intuitive. Many of the commands have seemingly odd names or syntax, the reasons for which usually date back many years to the early days of this system. And, although many of the commands may appear to be similar to their counterparts in the Windows command-line interpreter, there are important differences.

Instead of getting into the dark mesh of text processing, shell syntax, and other issues, in this chapter we strive to cover the basic commands needed to get you up to speed with the system if you're coming from a non-Unix environment. This chapter is far from complete; a real beginner's Unix tutorial would take an entire book. It's our hope that this chapter will give you enough to keep you going in your adventures with Linux, and that you'll invest in some more advanced books once you have a need to do so. We'll give you enough background to make your terminal usable, keep track of jobs, and enter essential commands.

Part 2 of this book contains material on system administration and maintenance. This is by far the most important part of the book for anyone running his own Linux system. If you are completely new to Unix, the material found in Part II should be easy to follow once you've completed the tutorial here.

One big job we merely touch on in this chapter is how to edit files. It's one of the first things you need to learn on any operating system. The two most popular editors for Linux, vi and Emacs, are discussed in Chapter 19.

Let's assume that your installation went completely smoothly, and you are facing the following prompt on your screen:

Additional content appearing in this section has been removed.
Purchase this book now or read it online at Safari to get the whole thing!

Logging In

Content preview·Buy reprint rights for this chapter

Let's assume that your installation went completely smoothly, and you are facing the following prompt on your screen:

Linux login 
:

Some Linux users are not so lucky; they have to perform some heavy tinkering when the system is still in a raw state or in single-user mode. But for now, we'll talk about logging into a functioning Linux system.

Logging in, of course, distinguishes one user from another. It lets several people work on the same system at once and makes sure that you are the only person to have access to your files.

You may have installed Linux at home and are thinking right now, "Big deal. No one else shares this system with me, and I'd just as soon not have to log in." But logging in under your personal account also provides a certain degree of protection: your account won't have the ability to destroy or remove important system files. The system administration account (covered in the next chapter) is used for such touchy matters.

If you connect your computer to the Internet, even via a modem, make sure you set nontrivial passwords on all your accounts. Use punctuation and strings that don't represent real words or names. Although Unix systems are not as susceptible to random brute-force attacks from the outside world as Windows systems are (according to some sources, it takes about 20 minutes from connecting a Windows box to the Internet until that computer is attacked, whereas it takes about 40 minutes to download the security fixes from Microsoft), you certainly do not want anybody to snoop around in your files.

Note that some distributions install a so-called graphical login manager right away, so you might not be greeted by the somewhat arcane login: prompt in white letters on black background, but with a fancy graphical login screen, possibly even presenting you with the user accounts available on your system (maybe even with a little picture for each user) as well as different modes to log into. The basic login procedure is the same as described here, however: you still type your username and password.

You were probably asked to set up a login account for yourself when you installed Linux. If you have such an account, type the name you chose at the

Additional content appearing in this section has been removed.
Purchase this book now or read it online at Safari to get the whole thing!

Setting a Password

Content preview·Buy reprint rights for this chapter

If you don't already have a password, we recommend you set one. Just enter the command passwd. The command will prompt you for a password and then ask you to enter it a second time to make sure you enter it without typos.

There are standard guidelines for choosing passwords so that they're hard for other people to guess. Some systems even check your password and reject any that don't meet the minimal criteria. For instance, it is often said that you should have at least six characters in the password. Furthermore, you should mix uppercase and lowercase characters or include characters other than letters and digits.

If you think it is a good idea to pick an ordinary, but rarely used word as your password, think again. There are password attack programs available that come with an English dictionary and just try all words in that dictionary in order to find the correct one so that the account can be compromised. Also, never use the account name for the password. This is sometimes called a "joe," and is likely to be the first thing a password attacker is going to try.

A good trick for choosing a good password is to take a full phrase that you can remember (maybe a line from your favorite song), and then just take the first letters. Then blend in a digit and maybe a special character. For example, if your line is I'd really like to go fishing now, your password could be Irl2gfn!. But do not use exactly this one; the fact that it has been published in this book makes it a bad password. There are even programs available (not unlikely integrated into the graphical user management tools of your distribution) that generate a random password from random characters, but of course these passwords are difficult to remember—if you have to write the password down in order to remember it, it is a bad password as well.

To change your password, just enter the passwd command again. It prompts you for your old password (to make sure you're you) and then lets you change it.

Additional content appearing in this section has been removed.
Purchase this book now or read it online at Safari to get the whole thing!

Virtual Consoles

Content preview·Buy reprint rights for this chapter

As a multiprocessing system, Linux gives you a number of interesting ways to do several things at once. You can start a long software installation and then switch to reading mail or compiling a program simultaneously.

Most Linux users, when they want this asynchronous access, will employ the X Window System (see Chapter 16). But before you get X running, you can do something similar through virtual consoles. This feature appears on a few other versions of Unix, but is not universally available.

To try out virtual consoles , hold down the left Alt key and press one of the function keys, F1 through F8. As you press each function key, you see a totally new screen complete with a login prompt. You can log in to different virtual consoles just as if you were two different people, and you can switch between them to carry out different activities. You can even run a complete X session in each console. The X Window System will use virtual console 7 by default. So if you start X and then switch to one of the text-based virtual consoles, you can go back again to X by typing Alt-F7. If you discover that the Alt-+ function key combination brings up an X menu or some other function instead of switching virtual consoles, use Ctrl + Alt + function key. You can even have two X servers running the X Window System; the second one would then be on virtual console 8.

Additional content appearing in this section has been removed.
Purchase this book now or read it online at Safari to get the whole thing!

Popular Commands

Content preview·Buy reprint rights for this chapter

The number of commands on a typical Unix system is enough to fill a few hundred reference pages. And you can add new commands too. The commands we'll tell you about here are just enough to navigate and to see what you have on the system.

As with Windows and virtually every modern computer system, Unix files are organized into a hierarchical directory structure. Unix imposes no rules about where files have to be, but conventions have grown up over the years. Thus, on Linux you'll find a directory called /home where each user's files are placed. Each user has a subdirectory under /home. So if your login name is mdw, your personal files are located in /home/mdw. This is called your home directory. You can, of course, create more subdirectories under it.

If you come from a Windows system, the slash (/) as a path separator may look odd to you because you are used to the backslash (\). There is nothing tricky about the slash. Slashes were actually used as path separators long before people even started to think about MS-DOS or Windows. The backslash has a different meaning on Unix (turning off the special meaning of the next character, if any).

As you can see, the components of a directory are separated by slashes. The term pathname is often used to refer to this slash-separated list.

What directory is /home in? The directory named /, of course. This is called the root directory. We have already mentioned it when setting up filesystems.

When you log in, the system puts you in your home directory. To verify this, use the "print working directory," or pwd , command:

$ pwd
/home/mdw

The system confirms that you're in /home/mdw.

You certainly won't have much fun if you have to stay in one directory all the time. Now try using another command, cd , to move to another directory:

$ cd /usr/bin
$ pwd
/usr/bin
$ cd

Where are we now? A cd with no arguments returns us to our home directory. By the way, the home directory is often represented by a tilde (~). So the string ~/programs means that programs is located right under your home directory.

While we're thinking about it, let's make a directory called

Additional content appearing in this section has been removed.
Purchase this book now or read it online at Safari to get the whole thing!

Shells

Content preview·Buy reprint rights for this chapter

As we said before, logging into the system in console mode puts you into a shell. If your system is configured with a graphical login, logging in brings you to the graphical interface where you can open an xterm (or similar) window in order to get a shell. The shell interprets and executes all your commands. Let's look a bit at different shells before we keep going, because they're going to affect some of the material coming up.

If it seems confusing that Unix offers many different shells, just accept it as an effect of evolution. Believe us, you wouldn't want to be stuck using the very first shell developed for Unix, the Bourne shell. Although it was a very powerful user interface for its day (the mid-1970s), it lacked a lot of useful features for interactive use—including the ones shown in this section. So other shells have been developed over time, and you can now choose the one that best suits your way of working.

Some of the shells available on Linux are as follows:

bash

Bourne Again shell. The most commonly used (and most powerful) shell on Linux. POSIX-compliant, compatible with the Bourne shell, created and distributed by the GNU project (Free Software Foundation). Offers command-line editing, history substitution, and Bourne shell compatibility.

csh

C shell. Developed at Berkeley. Mostly compatible with the Bourne shell for interactive use, but has a very different interface for programming. Does not offer command-line editing, although it does have a sophisticated alternative called history substitution. On Linux, csh is just another name for the newer tcsh.

ksh

Korn shell. Perhaps the most popular on Unix systems generally, and the first to introduce modern shell techniques (including some borrowed from the C shell) into the Bourne shell. Compatible with the Bourne shell. Offers command-line editing.

sh

Bourne shell. The original shell. Does not offer command-line editing.

tcsh

Enhanced C shell. Offers command-line editing.

zsh

Z shell. The newest of the shells. Compatible with the Bourne shell. Offers command-line editing. Has very powerful completion features. If you do not know any shell yet, and your Linux distribution carries

Additional content appearing in this section has been removed.
Purchase this book now or read it online at Safari to get the whole thing!

Useful Keys and How to Get Them to Work

Content preview·Buy reprint rights for this chapter

When you type a command, pressing the Backspace key should remove the last character. Ctrl-U should delete the line from the cursor to the beginning of the line; thus, this key combination will delete the whole line if the cursor is at the end of the line. When you have finished entering a command, and it is executing, Ctrl-C should abort it, and Ctrl-Z should suspend it. (When you want to resume the suspended program, enter fg for "foreground.")

Ctrl-S stops the terminal output until you turn it off again with Ctrl-Q. This is probably less useful today, as most terminal emulations provide scrolling facilities anyway, but it's important to know if you have hit Ctrl-S by accident and the terminal all of a sudden "becomes unresponsive." Just hit Ctrl-Q to make it respond again; it was just waiting for you.

If any of these keys fail to work, your terminal is not configured correctly for some reason. You can fix it through the stty command. Use the syntax:

stty function key

where function is what you want to do, and key is the key that you press. Specify a control key by putting a circumflex (^) in front of the key.

Here is a set of sample commands to set up the functions described earlier:

$ stty erase ^H
$ stty kill ^U
$ stty intr ^C
$ stty susp ^Z

The first control key shown, ^H, represents the ASCII code generated by the Backspace key.

By the way, you can generate a listing of your current terminal settings by entering stty -a. But that doesn't mean you can understand the output: stty is a complicated command with many uses, some of which require a lot of knowledge about terminals.

Here is another use of stty that can prove useful quite often: if your shell gets confused (as can often happen if you output binary data to it), and does not react as you are used to, try entering:

$ stty sane

That will usually succeed in bringing the shell to reason and making it operate as expected again.

Additional content appearing in this section has been removed.
Purchase this book now or read it online at Safari to get the whole thing!

Typing Shortcuts

Content preview·