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

Everything is a file


Under Linux, there is a well-known expression:

On a Linux system, everything is a file; if something is not a file, it is a process.

While this is not strictly 100% true, it is true for at least 90% of things you will encounter on Linux, definitely if you're not very advanced yet. Even though, in general, this rule works out, it has some extra notes. While most stuff on Linux is a file, there are different file types, seven to be exact. We'll discuss them all in the coming pages. You will probably not use all seven; however, having basic knowledge about them all gives you a better understanding about Linux in general, something which is never a bad thing!

Different types of files

The seven types of files are as follows, denoted with the character used by Linux to represent them:

Type

Explanation

-: Normal file

A regular file, containing text or bytes

d: Directory

A directory, which can contain other directories and regular files

l: Symlink

Symbolic link, used as a shortcut

s: Socket...