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Learning the bash Shell, 2nd Edition

Release Date: January 1998

Pages: 336

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The first thing users of the Linux operating system come face to face with is the shell. "Shell" is the UNIX term for a user interface to the system -- something that lets you communicate with the computer via the keyboard and display. Bash, the Free Software Foundation's "Bourne Again Shell," is the default shell for Linux, the popular free UNIX-like operating system. It's also a replacement for the standard UNIX Bourne shell, which serves both as a user interface and as a programming language. Like the FSF's other tools, bash is more than a mere replacement: it extends the Bourne shell in many ways. Features include command line editing, key bindings, integrated programming features, command completion, control structures (especially the select construct, which enables you to create menus easily), and new ways to customize your environment. Whether you want to use bash for its user interface or its programming features you will find Learning the bash Shell a valuable guide. The book covers all of bash's features, both for interactive use and programming. If you are new to shell programming, Learning the bash Shell provides an excellent introduction, covering everything from the most basic to the most advanced features, like signal handling and command line processing. If you've been writing shell scripts for years, it offers a great way to find out what the new shell offers. The book is full of examples of shell commands and programs that are designed to be useful in your everyday life as a user, not just to illustrate the feature being explained. All of these examples are freely available to you online on the Internet. This second edition covers all of the features of bash Version 2.0, while still applying to bash Version 1.x. New features include the addition of one-dimensional arrays, parameter expansion, and more pattern-matching operations. bash 2.0 provides even more conformity with POSIX.2 standards, and in POSIX.2 mode is completely POSIX.2 conformant. This second edition covers several new commands, security improvements, additions to ReadLine, improved configuration and installation, and an additional programming aid, the bash shell debugger. With this book you'll learn:

How to install bash as your login shell
The basics of interactive shell use, including UNIX file and directory structures, standard I/O, and background jobs
Command line editing, history substitution, and key bindings
How to customize your shell environment without programming
The nuts and bolts of basic shell programming, flow control structures, command-line options and typed variables
Process handling, from job control to processes, coroutines and subshells
Debugging techniques, such as trace and verbose modes
Techniques for implementing system-wide shell customization and features related to system security

Chapter 1 bash Basics
1. What Is a Shell?
2. Scope of This Book
3. History of UNIX Shells
4. Getting bash
5. Interactive Shell Use
6. Files
7. Input and Output
8. Background Jobs
9. Special Characters and Quoting
10. Help
Chapter 2 Command-Line Editing
1. Enabling Command-Line Editing
2. The History File
3. emacs Editing Mode
4. vi Editing Mode
5. The fc Command
6. History Expansion
7. readline
8. Keyboard Habits
Chapter 3 Customizing Your Environment
1. The .bash_profile, .bash_logout, and .bashrc Files
2. Aliases
3. Options
4. Shell Variables
5. Customization and Subprocesses
6. Customization Hints
Chapter 4 Basic Shell Programming
1. Shell Scripts and Functions
2. Shell Variables
3. String Operators
4. Command Substitution
5. Advanced Examples: pushd and popd
Chapter 5 Flow Control
1. if/else
2. for
3. case
4. select
5. while and until
Chapter 6 Command-Line Options and Typed Variables
1. Command-Line Options
2. Typed Variables
3. Integer Variables and Arithmetic
4. Arrays
Chapter 7 Input/Output and Command-Line Processing
1. I/O Redirectors
2. String I/O
3. Command-Line Processing
Chapter 8 Process Handling
1. Process IDs and Job Numbers
2. Job Control
3. Signals
4. trap
5. Coroutines
6. Subshells
7. Process Substitution
Chapter 9 Debugging Shell Programs
1. Basic Debugging Aids
2. A bash Debugger
Chapter 10 bash Administration
1. Installing bash as the Standard Shell
2. Environment Customization
3. System Security Features
Chapter 11 bash for Your System
1. Obtaining bash
2. Unpacking the Archive
3. What’s in the Archive
4. Who Do I Turn to?

Appendix Related Shells
1. The Bourne Shell
2. The IEEE 1003.2 POSIX Shell Standard
3. The Korn Shell
4. pdksh
5. Workalikes on PC Platforms
Appendix Reference Lists
1. Invocation
2. Built-In Commands and Reserved Words
3. Environment Variables
4. Test Operators
5. set Options
6. shopt Options
7. I/O Redirection
8. emacs Mode Commands
9. vi Control Mode Commands
Appendix Loadable Built-Ins
Appendix Syntax
1. Reserved Words
2. BNF for bash
Appendix Obtaining Sample Programs
1. FTP
2. FTPMAIL
Colophon

Books & Videos

Learning the bash Shell, 2nd Edition

Read on Safari with a 10-day trial

Table of Contents

Chapter 1 bash Basics

What Is a Shell?

Scope of This Book

History of UNIX Shells

Getting bash

Interactive Shell Use

Files

Input and Output

Background Jobs

Special Characters and Quoting

Help

Chapter 2 Command-Line Editing

Enabling Command-Line Editing

The History File

emacs Editing Mode

vi Editing Mode

The fc Command

History Expansion

readline

Keyboard Habits

Chapter 3 Customizing Your Environment

The .bash_profile, .bash_logout, and .bashrc Files

Aliases

Options

Shell Variables

Customization and Subprocesses

Customization Hints

Chapter 4 Basic Shell Programming

Shell Scripts and Functions

Shell Variables

String Operators

Command Substitution

Advanced Examples: pushd and popd

Chapter 5 Flow Control

if/else

for

case

select

while and until

Chapter 6 Command-Line Options and Typed Variables

Command-Line Options

Typed Variables

Integer Variables and Arithmetic

Arrays

Chapter 7 Input/Output and Command-Line Processing

I/O Redirectors

String I/O

Command-Line Processing

Chapter 8 Process Handling

Process IDs and Job Numbers

Job Control

Signals

trap

Coroutines

Subshells

Process Substitution

Chapter 9 Debugging Shell Programs

Basic Debugging Aids

A bash Debugger

Chapter 10 bash Administration

Installing bash as the Standard Shell

Environment Customization

System Security Features

Chapter 11 bash for Your System

Obtaining bash

Unpacking the Archive

What’s in the Archive

Who Do I Turn to?

Appendix Related Shells

The Bourne Shell

The IEEE 1003.2 POSIX Shell Standard

The Korn Shell

pdksh

Workalikes on PC Platforms

Appendix Reference Lists

Invocation