This section describes the information that each chapter covers and explains how that information can help you take advantage of the power of Linux. You may want to review the table of contents for more detail.
Chapter 1 Welcome to Linux Presents background information on Linux. This chapter covers the history of Linux, explains how the GNU Project helped Linux get started, and discusses some of Linux's important features that distinguish it from other operating systems.
Part I: The Linux Operating System
tip: Experienced users may want to skim Part I
If you have used a UNIX/Linux system before, you may want to skim or skip some or all of the chapters in Part I. All readers should take a look at " Conventions Used in This Book" (page 22), which explains the typographic conventions that this book uses, and "Getting the Facts: Where to Find Documentation" (page 29), which points you toward both local and remote sources of Linux documentation.
Part I introduces Linux and gets you started using it.
Chapter 2 Getting Started Explains the typographic conventions that this book uses to make explanations clearer and easier to read. This chapter provides basic information and explains how to log in, change your password, give Linux commands using the shell, and find system documentation.
Chapter 3 Command Line Utilities Explains the command line interface (CLI) and briefly introduces more than 30 command line utilities. Working through this chapter gives you a feel for Linux and introduces some of the tools you will use day in and day out. The utilities covered in this chapter include
grep, which searches through files for strings of characters;
unix2dos, which converts Linux text files to Windows format;
tar, which creates archive files that can hold many other files;
bzip2 and gzip, which compress files so that they take up less space on disk and allow you to transfer them over a network more quickly; and
diff, which displays the differences between two text files.
Chapter 4 The Linux Filesystem Discusses the Linux hierarchical filesystem, covering files, filenames, pathnames, working with directories, access permissions, and hard and symbolic links. Understanding the filesystem allows you to organize your data so that you can find information quickly. It also enables you to share some of your files with other users while keeping other files private.
Chapter 5 The Shell Explains how to use shell features to make your work faster and easier. All of the features covered in this chapter work with both bash and tcsh. This chapter discusses
Using command line options to modify the way a command works;
How a minor change in a command line can redirect input to a command to come from a file instead of the keyboard;
How to redirect output from a command to go to a file instead of the screen;
Using pipes to send the output of one utility directly to another utility so that you can solve problems right on the command line;
Running programs in the background so that you can work on one task while Linux is working on a different one; and
Using the shell to generate filenames to save you time spent on typing and help you when you do not remember the exact name of a file.
Part II: The Editors
Part II covers two classic, powerful Linux command line text editors. Most Linux distributions include the vim text editor, an "improved" version of the widely used vi editor, as well as the popular GNU emacs editor. Text editors enable you to create and modify text files that can hold programs, shell scripts, memos, and input to text formatting programs. Because Linux system administration involves editing text-based configuration files, skilled Linux administrators are adept at using text editors.
Chapter 6 The vim Editor Starts with a tutorial on vim and then explains how to use many of the advanced features of vim, including special characters in search strings, the General-Purpose and Named buffers, parameters, markers, and execution of commands from vim. The chapter concludes with a summary of vim commands.
Chapter 7 The emacs Editor Opens with a tutorial and then explains many of the features of the emacs editor as well as how to use the META, ALT, and ESCAPE keys. The chapter also covers key bindings, buffers, and incremental and complete searching for both character strings and regular expressions. In addition, it details the relationship between Point, the cursor, Mark, and Region. It also explains how to take advantage of the extensive online help facilities available from emacs. Other topics covered include cutting and pasting, using multiple windows and frames, and working with emacs modes specifically C mode, which aids programmers in writing and debugging C code. Chapter 7 concludes with a summary of emacs commands.
Part III: The Shells
Part III goes into more detail about bash and introduces the TC Shell (tcsh).
Chapter 8 The Bourne Again Shell Picks up where Chapter 5 leaves off, covering more advanced aspects of working with a shell. For examples it uses the Bourne Again Shell bash, the shell used almost exclusively for system shell scripts. Chapter 8 describes how to
Use shell startup files, shell options, and shell features to customize your shell;
Use job control to stop jobs and move jobs from the foreground to the background and vice versa;
Modify and reexecute commands using the shell history list;
Create aliases to customize commands;
Work with user-created and keyword variables in shell scripts;
Set up functions, which are similar to shell scripts but can execute more quickly;
Write and execute simple shell scripts; and
Redirect error messages so that they go to a file instead of the screen.
Chapter 9 The TC Shell Describes tcsh and covers features that are common to and different between bash and tcsh. This chapter explains how to
Run tcsh and change your default shell to tcsh;
Redirect error messages so that they go to files instead of the screen;
Use control structures to alter the flow of control within shell scripts;
Work with tcsh array and numeric variables; and
Use shell builtin commands.
Part IV: Programming Tools
Part IV covers programming under Linux. It discusses the C programming environment, the use of bash as a programming language, and ways to write programs using gawk and sed.
Chapter 10 Programming Tools Introduces Linux's exceptional programming environment. This chapter
Explains how to invoke the GNU gcc compiler;
Describes how to use make to keep a set of programs up-to-date;
Explains how to debug a C program using gdb;
Describes how to work with shared libraries;
Explains how to set up and use CVS to manage and track program modules in a software development project; and
Discusses system calls and explains how you can use them to initiate kernel operations.
Once you have mastered the basics of Linux, you can use your knowledge to build more complex and specialized programs, using the shell as a programming language.
Chapter 11 Programming the Bourne Again Shell Shows how to use bash to write advanced shell scripts. This chapter discusses
Control structures such as if...then...else and case;
Variables, including locality of variables;
Arithmetic and logical (Boolean) expressions; and
Some of the most useful shell builtin commands, including exec, trap, and getopts.
Chapter 11 poses two complete shell programming problems and then shows you how to solve them step by step. The first problem uses recursion to create a hierarchy of directories. The second problem develops a quiz program and shows you how to set up a shell script that interacts with a user and how the script processes data. (The examples in Part V also demonstrate many features of the utilities you can use in shell scripts.)
Chapter 12 The gawk Pattern Processing Language Explains how to write programs using the powerful gawk language that filter data, write reports, and retrieve data from the Internet. The advanced programming section describes how to set up two-way communication with another program using a coprocess and how to obtain input over a network instead of from a local file.
Chapter 13 The sed Editor Describes sed, the noninteractive stream editor that finds many applications as a filter within shell scripts. This chapter discusses how to use sed's buffers to write simple yet powerful programs and includes many examples.
Part V: Command Reference
Linux includes hundreds of utilities. Chapters 11 and 12 as well as Part V provide extensive examples of the use of more than 80 of the most important utilities with which you can solve problems without resorting to programming in C. If you are already familiar with UNIX/Linux, this part of the book will be a valuable, easy-to-use reference. If you are not an experienced user, it will serve as a useful supplement while you are mastering the earlier sections of the book.
Although the descriptions of the utilities in Chapters 11 and 12 and Part V are presented in a format similar to that used by the Linux manual (man) pages, they are much easier to read and understand. These utilities were chosen because you will work with them day in and day out (for example, ls and cp), because they are powerful tools that are especially useful in shell scripts (sort, paste, and test), because they help you work with your Linux system (ps, kill, and fsck), or because they enable you to communicate with other systems (ssh, scp, and ftp). Each utility description includes complete explanations of its most useful options. The "Discussion" and "Notes" sections present tips and tricks for using the utility to full advantage. The "Examples" sections demonstrate how to use these utilities in real life, alone and together with other utilities to generate reports, summarize data, and extract information. Take a look at the "Examples" sections for gawk (more than 20 pages, starting on page 537), ftp (page 674), and sort (page 764) to see how extensive these sections are.
Part VI: Appendixes
Part VI includes the appendixes, the glossary, and the index.
Appendix A Regular Expressions Explains how to use regular expressions to take advantage of the hidden power of Linux. Many utilities, including grep, sed, vim, and gawk, accept regular expressions in place of simple strings of characters. A single regular expression can match many simple strings.
Appendix B Help Details the steps typically used to solve the problems you may encounter with a Linux system. This appendix also includes many links to Web sites that offer documentation, useful Linux information, mailing lists, and software.
Appendix C Keeping the System Up-to-date Describes how to use tools to download software and keep your system current. This appendix includes information on
yum Downloads software from the Internet, keeping a system up-to-date and resolving dependencies as it goes.
Apt An alternative to yum for keeping a system current.
BitTorrent Good for distributing large amounts of data such as Linux installation CDs.
Glossary Defines more than 500 terms that pertain to the use of Linux.
Index Helps you find the information you want quickly.