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

Dealing with user input


So far, we've been dealing with really static scripts. While it's fun to have a story available for everyone to print out, it hardly qualifies as a functional shell script. At the very least, it's not something you are going to use often! So, we'd like to introduce a very important concept in shell scripting: user input.

Basic input

At a very basic level, everything that you put on the command line right after calling the script can be used as input. However, it is up to the script to use it! For example, consider the following situation:

reader@ubuntu:~/scripts/chapter_08$ ls
hello-int.sh hello-world-variable.sh name.sh variable-naming-proper.sh variable-naming.sh
reader@ubuntu:~/scripts/chapter_08$ bash name.sh 
There once was a guy named Sebastiaan. Sebastiaan enjoyed Linux and Bash so much that he wrote a book about it! Sebastiaan really hopes everyone enjoys his book.
reader@ubuntu:~/scripts/chapter_08$ bash name.sh Sanne
There once was a guy named Sebastiaan. Sebastiaan...