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What This Book Offers | 5
Introduction
Every distribution of Linux is slightly different. There are variations in directory
structure, choice of standard utilities, and software versions, but you’ll find that
the commands we document are the ones you use most of the time, and that they
work the same on all distributions. Note, though, that some commands are only
available with certain devices or configurations, or have alternatives that may be
preferred in your environment. Basic commands, programming utilities, system
administration, and network administration are all covered. However, some areas
were so big that we had to leave them out. The many applications that depend on
the X Window System didn’t make the cut. Nor did the many useful program-
ming languages—such as Java, Perl, and Python—with which users can vastly
expand the capabilities of their systems. XML isn’t covered here, either. These
subjects would stretch the book out of its binding.
Linux in a Nutshell doesn’t teach you Linux—it is, after all, a quick reference—
but novices as well as highly experienced users will find it of great value. When
you have some idea of what command you want but aren’t sure just how it works
or what combinations of options give you the exact output required, this book is
the place to turn. It can also be an eye-opener, making you aware of options that
you never knew about before.
Once you’ve installed Linux, the first thing you need to do is get to know the
common utilities run from the shell prompt. If you know absolutely nothing
about Unix, we recommend you read a basic guide (introductory chapters in the
O’Reilly books Learning Red Hat Enterprise Linux and Fedora, by Bill McCarty,
and Running Linux, mentioned previously, can get you started). This chapter and
Chapter 2 offer a context for understanding different kinds of commands
(including commands for programming, system administration, and network
administration). Chapter 3 is the central focus of the book, containing about one
half its bulk.
The shorter chapters immediately following Chapter 3 help you get your system
set up. Since most users do not want to completely abandon other operating
systems (whether a Microsoft Windows system or some Unix flavor), many users
opt for a dual-boot system, with Linux residing on the same computer as other
operating systems. Users can then boot to the system they need for a particular
job. Chapter 4 describes the commonly used booting options on Intel systems,
including LILO (Linux Loader) and GRUB (the GRand Unified Bootloader).
Chapter 5 covers the Red Hat package manager (rpm)—which is supported by
many distributions, including Red Hat Enterprise Linux, Fedora, SUSE, and
Mandriva—and the Debian package-management system, which is used by such
distributions as Ubuntu, Knoppix, and Gnoppix. It also describes some of the
frontend package-management tools that simplify package management and auto-
matically resolve dependencies. These tools include yum for rpm-based systems
and aptitude and synaptic for Debian-based systems. Package managers are
useful for installing and updating software; they make sure you have all the files
you need in the proper versions.
All commands are interpreted by the shell. The shell is simply a program that
accepts commands from the user and executes them. Different shells sometimes
use slightly different syntax to mean the same thing. Under Linux, the standard
shell is bash. Others, such as the ksh Korn shell, the tcsh enhanced C shell, and