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)

Scripts, Functions, and Aliases

In the previous chapter, we explored some of the most important commands provided to you by the Bash shell and by a Unix system that implements the POSIX standard. These commands have many uses on their own, and they can additionally serve as the basis for making your own custom commands, to perform specific tasks that you need and remember them for convenience in the future.

This chapter explores three different types of custom commands that you can write to use in your Bash scripts or on the Bash command line:

  • Aliases: Can expand a word into a command line string
  • Functions: A way to write a command from a set of other commands, much more versatile than aliases
  • Scripts: Take the form of programs in files on your system, and unlike aliases and functions, can be used outside of Bash

We'll look at each of these in turn, demonstrating them with...