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)

Keeping scripts flexible

Allow your script's users to use the tool in whatever way they may need. For example, avoid hardcoding filenames to be read in your scripts, if you can; instead, allow the user to provide filenames as options or arguments.

If your script works on files, consider making it work the same way the classic Unix text filtering tools do. If there are no arguments, read any data needed from the standard input:

$ myscript

If there are arguments, read the data from (or make changes to) all of those files, in order:

$ myscript file1 file2

If one of the arguments is a dash, read from the standard input at that point in the argument loop, to allow us to provide a prefix and a suffix to the data:

$ myscript file1 - file2

These conventions are well-known to Unix users, and they will appreciate finding this flexibility in your scripts.