Book Image

Bash Quick Start Guide

By : Tom Ryder
Book Image

Bash Quick Start Guide

By: Tom Ryder

Overview of this book

Bash and shell script programming is central to using Linux, but it has many peculiar properties that are hard to understand and unfamiliar to many programmers, with a lot of misleading and even risky information online. Bash Quick Start Guide tackles these problems head on, and shows you the best practices of shell script programming. This book teaches effective shell script programming with Bash, and is ideal for people who may have used its command line but never really learned it in depth. This book will show you how even simple programming constructs in the shell can speed up and automate any kind of daily command-line work. For people who need to use the command line regularly in their daily work, this book provides practical advice for using the command-line shell beyond merely typing or copy-pasting commands into the shell. Readers will learn techniques suitable for automating processes and controlling processes, on both servers and workstations, whether for single command lines or long and complex scripts. The book even includes information on configuring your own shell environment to suit your workflow, and provides a running start for interpreting Bash scripts written by others.
Table of Contents (10 chapters)


The GNU Bourne-Again Shell, or Bash, is the best-known Bourne-style shell in the world, and is installed or available for installation on a huge variety of Unix-like systems. Even professionals who don't do a lot of work with Unix or Linux will need to use the Bash shell occasionally.

Bash is a language of contradictions; while it's the best-known and most widely-deployed shell of its kind, it's perhaps also one of the least-understood tools, with a terse syntax that's relatively unique among modern programming languages and can seem bizarre even to experienced users. Bash is powerful in some ways, and very limited in others. It's clear, elegant, and expressive in some ways, and terse, clumsy, and bewildering in others.

Because it's so powerful and yet so complex, and because so many computer professionals can't avoid using it at least occasionally, Bash is often learned by way of a kind of "tradition;" demonstrations by experienced administrators, reading others' scripts, copying and pasting, and asking questions and reading answers on the internet. This leads to a lot of "cargo-cult programming," and a lot of bad practices that make things unnecessarily confusing at best, and downright dangerous at worst. The available documentation for Bash is often unhelpful in addressing this problemit often teaches the same bad practices, and even when it's correct, as the official Bash manual page is, it's often too complicated and assumes too much knowledge for new users to understand it.

To avoid all that, we'll start learning good Bash from first principles, and focus almost exclusively on writing the language well, in both interactive and batch mode. By the end of this book, you'll have a firm grasp on how to write Bash shell script in a robust and understandable way, and be in a position to notice bad habits and dangerous "hot spots" in others' code. You'll have a great grasp on the problems for which shell script is a perfect solution, and writing it will be a lot more efficient, and maybe even fun.