Learning the Korn Shell, Second Edition

Description

Learning the Korn Shell is the key to gaining control of the Korn shell and becoming adept at using it as an interactive command and scripting language. Readers will learn how to write many applications more easily and quickly than with other high-level languages. A solid offering for many years, this newly revised title inherits a long tradition of trust among computer professionals who want to learn or refine an essential skill.

Full Description

The Korn shell is an interactive command and scripting language for accessing Unix® and other computer systems. As a complete and high-level programming language in itself, it's been a favorite since it was developed in the mid 1980s by David G. Korn at AT&T Bell Laboratories. Knowing how to use it is an essential skill for serious Unix users. Learning the Korn Shell shows you how to use the Korn shell as a user interface and as a programming environment. Writing applications is often easier and quicker with Korn than with other high-level languages. Because of this, the Korn shell is the most often used shell in commercial environments and among inexperienced users. There are two other widely used shells, the Bourne shell and the C shell. The Korn shell, or ksh, has the best features of both, plus many new features of its own. ksh can do much to enhance productivity and the quality of a user's work, both in interacting with the system, and in programming. The new version, ksh93, has the functionality of other scripting languages such as awk, icon, Perl, rexx, and tcl. Learning the Korn Shell is the key to gaining control of the Korn shell and becoming adept at using it as an interactive command and scripting language. Prior programming experience is not required in order to understand the chapters on basic shell programming. Readers will learn how to write many applications more easily and quickly than with other high-level languages. In addition, readers will also learn about Unix utilities and the way the Unix operating system works in general. The authors maintain that you shouldn't have to be an internals expert to use and program the shell effectively. The second edition covers all the features of the current version of the Korn shell, including many new features not in earlier versions of ksh93, making it the most up-to-date reference available on the Korn shell. It compares the current version of the Korn shell to several other Bourne-compatible shells, including several Unix emulation environments for MS-DOS and Windows. In addition, it describes how to download and build ksh93 from source code. A solid offering for many years, this newly revised title inherits a long tradition of trust among computer professionals who want to learn or refine an essential skill.

Table of Contents

Chapter 1 Korn Shell Basics
1. What Is a Shell?
2. Scope of This Book
3. History of Unix Shells
4. Getting the 1993 Korn Shell
5. Interactive Shell Use
6. Files
7. Input and Output
8. Background Jobs
9. Special Characters and Quoting
Chapter 2 Command-Line Editing
1. Enabling Command-Line Editing
2. The History File
3. Emacs Editing Mode
4. Vi Editing Mode
5. The hist Command
6. Finger Habits
Chapter 3 Customizing Your Environment
1. The .profile File
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. Compound Variables
4. Indirect Variable References (namerefs)
5. String Operators
6. Command Substitution
7. 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. Numeric Variables and Arithmetic
3. Arithmetic for
4. Arrays
5. typeset
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. Shell Subprocesses and Subshells
Chapter 9 Debugging Shell Programs
1. Basic Debugging Aids
2. A Korn Shell Debugger
Chapter 10 Korn Shell Administration
1. Installing the Korn Shell as the Standard Shell
2. Environment Customization
3. Customizing the Editing Modes
4. System Security Features

Appendix A Related Shells
1. The Bourne Shell
2. The 1988 Korn Shell
3. The IEEE 1003.2 POSIX Shell Standard
4. dtksh
5. tksh
6. pdksh
7. bash
8. zsh
9. Workalikes on PC Platforms
Appendix B Reference Information
1. Invocation Options
2. Built-in Commands and Keywords
3. Predefined Aliases
4. Built-in Shell Variables
5. Test Operators
6. Options
7. Typeset Options
8. Arithmetic
9. Emacs Mode Commands
10. vi Control Mode Commands
11. Using getopts
Appendix C Building ksh from Source Code
1. Korn Shell Web Sites
2. What You Can Download
3. Building ksh
Appendix D AT&T ast Source Code License Agreement
Colophon

Product Details

Title:

Learning the Korn Shell, Second Edition

By:

Arnold Robbins, Bill Rosenblatt

Publisher:

O'Reilly Media

Formats:

Print
Safari Books Online

Print Release:

April 2002

Pages:

432

Print ISBN:

978-0-596-00195-7

| ISBN 10:

0-596-00195-9

Customer Reviews

About the Author

Arnold Robbins

Arnold Robbins, an Atlanta native, is a professional programmer and technical author. He has worked with Unix systems since 1980, when he was introduced to a PDP-11 running a version of Sixth Edition Unix. He has been a heavy AWK user since 1987, when he became involved with gawk, the GNU project's version of AWK. As a member of the POSIX 1003.2 balloting group, he helped shape the POSIX standard for AWK. He is currently the maintainer of gawk and its documentation. He is also coauthor of the sixth edition of O'Reilly's Learning the vi Editor. Since late 1997, he and his family have been living happily in Israel.

View Arnold Robbins's full profile page.

Colophon

Our look is the result of reader comments, our own experimentation, and feedback from distribution channels. Distinctive covers complement our distinctive approach to technical topics, breathing personality and life into potentially dry subjects. The animal on the cover of Learning the Korn Shell is a hawksbill turtle. The name "hawksbill" refers to its prominent hooked beak. This marine reptile is one of the smaller sea turtles, having a carapace (upper shell) length of about two feet and weighing about one hundred pounds. Among pelagic turtles, the hawksbill alone has the tendency to feed and breed in the same area, preferring the tropical shoals and reefs of the world's oceans.

Primarily carnivorous, the hawksbill feeds on crabs, fish, sponges, and jellyfish. The turtle's flesh can be poisonous; in some places, fisherman test for poison by throwing the turtle's liver to the crows. If the birds reject the liver, the hawksbill is toxic.

The hawksbill turtle is the sole source of authentic "tortoiseshell," which comes from the scutes, or outer layer of the carapace. Tortoiseshell has been harvested through the years-from ancient Egypt to the present-and is highly valued for its beauty and plasticity. As a result, the hawksbill is endangered. Illegal trade continues to threaten this species' existence. Leanne Soylemez was the production editor and proofreader for Learning the Korn Shell, Second Edition. Kate Briggs was the copyeditor. Mary Brady and Jane Ellin provided quality control. Brenda Miller wrote the index.

Edie Freedman designed the cover of this book. The cover image is a 19th-century engraving from the Dover Pictorial Archive. Emma Colby produced the cover layout with QuarkXPress 4.1 using Adobe's ITC Garamond font.

Melanie Wang and David Futato designed the interior layout based on a series design by Nancy Priest. The print version of this book was created by translating the DocBook XML markup of its source files into a set of gtroff macros using a filter developed at O'Reilly & Associates by Norman Walsh. Steve Talbott designed and wrote the underlying macro set on the basis of the GNU troff -mgs macros; Lenny Muellner adapted them to XML and implemented the book design. The GNU groff text formatter version 1.11.1 was used to generate PostScript output. The text and heading fonts are ITC Garamond Light and Garamond Book; the code font is Constant Willison. The illustrations that appear in the book were produced by Robert Romano, Jessamyn Read, and Chris Reilley, using Macromedia FreeHand 9 and Adobe Photoshop 6. This colophon was written by Michael Kalantarian.

O'Reilly Books & Videos

Learning the Korn Shell, Second Edition

Chapter 1 Korn Shell Basics

What Is a Shell?

Scope of This Book

History of Unix Shells

Getting the 1993 Korn Shell

Interactive Shell Use

Files

Input and Output

Background Jobs

Special Characters and Quoting

Chapter 2 Command-Line Editing

Enabling Command-Line Editing

The History File

Emacs Editing Mode

Vi Editing Mode

The hist Command

Finger Habits

Chapter 3 Customizing Your Environment

The .profile File

Aliases

Options

Shell Variables

Customization and Subprocesses

Customization Hints

Chapter 4 Basic Shell Programming

Shell Scripts and Functions

Shell Variables

Compound Variables

Indirect Variable References (namerefs)

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

Numeric Variables and Arithmetic

Arithmetic for

Arrays

typeset

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

Shell Subprocesses and Subshells

Chapter 9 Debugging Shell Programs

Basic Debugging Aids

A Korn Shell Debugger

Chapter 10 Korn Shell Administration

Installing the Korn Shell as the Standard Shell

Environment Customization

Customizing the Editing Modes

System Security Features

Appendix A Related Shells

The Bourne Shell

The 1988 Korn Shell

The IEEE 1003.2 POSIX Shell Standard

dtksh

tksh

pdksh

bash

zsh

Workalikes on PC Platforms

Appendix B Reference Information

Invocation Options

Built-in Commands and Keywords

Predefined Aliases

Built-in Shell Variables