Book Image

Learn Linux Shell Scripting – Fundamentals of Bash 4.4

By : Sebastiaan Tammer
Book Image

Learn Linux Shell Scripting – Fundamentals of Bash 4.4

By: Sebastiaan Tammer

Overview of this book

Shell scripts allow us to program commands in chains and have the system execute them as a scripted event, just like batch files. This book will start with an overview of Linux and Bash shell scripting, and then quickly deep dive into helping you set up your local environment, before introducing you to tools that are used to write shell scripts. The next set of chapters will focus on helping you understand Linux under the hood and what Bash provides the user. Soon, you will have embarked on your journey along the command line. You will now begin writing actual scripts instead of commands, and will be introduced to practical applications for scripts. The final set of chapters will deep dive into the more advanced topics in shell scripting. These advanced topics will take you from simple scripts to reusable, valuable programs that exist in the real world. The final chapter will leave you with some handy tips and tricks and, as regards the most frequently used commands, a cheat sheet containing the most interesting flags and options will also be provided. After completing this book, you should feel confident about starting your own shell scripting projects, no matter how simple or complex the task previously seemed. We aim to teach you how to script and what to consider, to complement the clear-cut patterns that you can use in your daily scripting challenges.
Table of Contents (24 chapters)
Title Page
About Packt
Contributors
Preface
Free Chapter
1
Introduction
Index

Summary


This chapter started with a recap of how positional parameters are used in Bash. We continued by showing you how most command-line tools we've introduced up until this point (and those we haven't) use flags, often as modifiers for script functionality, whereas positional parameters are used to indicate targets for the commands.

We then introduced a way for the reader to incorporate options and option arguments within their own scripts: by using the getopts shell builtin. We kicked this off by discussing the differences between the legacy program getopt and the newer builtin getopts, which we focused on for the rest of this chapter.

Since getopts only allows us to use short options (whereas getopt and some other command-line tools also use long options, denoted by double dashes), we showed you how this is not an issue due to the recognition of common short options such as -h, -v, and so on.

We properly introduced the getopts syntax with a few examples. We showed how you can use flags...