Book Image

Linux Command Line and Shell Scripting Bible - Third Edition

By : Richard Blum, Christine Bresnahan
Book Image

Linux Command Line and Shell Scripting Bible - Third Edition

By: Richard Blum, Christine Bresnahan

Overview of this book

The Linux command line enables you to type specific shell commands directly into the system to manipulate files and query system resources. Command line statements can be combined into short programs called shell scripts, a practice increasing in popularity due to its usefulness in automation. Linux is a robust system with tremendous potential, and Linux Command Line and Shell Scripting Bible opens the door to new possibilities. Linux Command Line and Shell Scripting Bible is your essential Linux guide. It contains new functional examples that are fully updated to align with the latest Linux features. Beginning with command line fundamentals, the book moves into shell scripting and shows you the practical application of commands in automating frequently performed functions. This book is a complete guide providing detailed instruction and expert advice working within this aspect of Linux. Whether used as a tutorial or as a quick reference, this book contains information that every Linux user should know.
Table of Contents (34 chapters)
Part I: The Linux Command Line
Part II: Shell Scripting Basics
Part III: Advanced Shell Scripting
Part IV: Creating Practical Scripts
End User License Agreement

What Is the dash Shell?

The Debian dash shell has had an interesting past. It's a direct descendant of the ash shell, a simple copy of the original Bourne shell available on Unix systems (see Chapter 1). Kenneth Almquist created a small-scale version of the Bourne shell for Unix systems and called it the Almquist shell, which was then shortened to ash. This original version of the ash shell was extremely small and fast but without many advanced features, such as command line editing or history features, making it difficult to use as an interactive shell.

The NetBSD Unix operating system adopted the ash shell and still uses it today as the default shell. The NetBSD developers customized the ash shell by adding several new features, making it closer to the Bourne shell. The new features include command line editing using both emacs and vi editor commands, as well as a history command to recall previously entered commands. This version of the ash shell is also used by the FreeBSD operating...