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The Ultimate Linux Shell Scripting Guide
The Ultimate Linux Shell Scripting Guide

The Ultimate Linux Shell Scripting Guide: Automate, Optimize, and Empower tasks with Linux Shell Scripting

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Profile Icon Donald A. Tevault
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$19.99 per month
Full star icon Full star icon Full star icon Full star icon Half star icon 4.8 (4 Ratings)
Paperback Oct 2024 696 pages 1st Edition
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Arrow left icon
Profile Icon Donald A. Tevault
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$19.99 per month
Full star icon Full star icon Full star icon Full star icon Half star icon 4.8 (4 Ratings)
Paperback Oct 2024 696 pages 1st Edition
eBook
$31.99 $35.99
Paperback
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Table of content icon View table of contents Preview book icon Preview Book

The Ultimate Linux Shell Scripting Guide

Interpreting Commands

To fulfill its job as the interface between the user and the operating system kernel, a shell has to perform five different functions. These functions include interpreting commands, setting variables, enabling input/output redirection, enabling pipelines, and allowing customization of a user’s working environment. In this chapter, we’ll look at how bash and zsh interpret commands. As an added bonus, much of what we’ll cover in the next few chapters will also help you prepare for certain Linux certification exams, such as the Linux Professional Institute or CompTIA Linux+ exams.

Topics in this chapter include:

  • Understanding the structure of a command
  • Executing multiple commands at once
  • Running commands recursively
  • Understanding the command history
  • Escaping and quoting

To follow along, you can use pretty much any Linux distro that you desire, as long as it’s running with either bash or...

Understanding the Structure of a Command

A handy thing to know for both real-life and any certification exams that you may take, is the structure of a command. Commands can consist of up to three parts, and there’s a certain order for the parts. Here are the parts and the order in which you’ll normally place them:

  • The command itself
  • Command options
  • Command arguments

If you plan to take a Linux certification exam, you’ll definitely want to remember this ordering rule. Later on though, we’ll see that some commands don’t always follow this rule.

Using Command Options

There are two general types of option switches:

  • Single-letter options: For most commands, a single-letter option is preceded by a single dash. Most of the time, two or more single-letter options can be combined with a single dash.
  • Whole-word options: For most commands, a whole word option is preceded by two dashes. Two or more whole...

Executing Multiple Commands at Once

From either the command-line or from within shell scripts, it’s handy to know how to combine multiple commands into one single command. In this section, I’ll demonstrate three ways to do that which are:

  • Running commands interactively
  • Using command sequences
  • Using the find utility

Running Commands Interactively

This is a form of shell-script programming, except that you’re just executing all commands from the command-line, instead of actually writing, saving, and executing a script. Here, you are creating a for loop – with each command of the loop on its own separate line – to perform a directory listing three times.

[donnie@fedora ~]$ for var in arg1 arg2 arg3
> do
> echo $var
> ls
> done
. . .
. . .
[donnie@fedora ~]$

At the end of each line, you’ll hit the Enter key. But, nothing will happen until you type the done command on the final line. The...

Running Commands Recursively

We’ve already shown you that the find utility is inherently recursive. That is, it will automatically search through the subdirectories of your specified search path without you having to tell it to. Most Linux commands aren’t that way, however. If you want them to work recursively, you’ll have to tell them to. For the most part, this is done with either the -R switch or the -r switch. (Some commands use –R, and some use –r. Something that you’ll eventually see for yourself is that there’s not a lot of consistency in how the different commands work with option switches.) Let’s see how it all works with a hands-on lab.

The examples in this section involve using the numeric method to set file and directory permissions. For anyone who’s not familiar with how to do that, I’ve provided a reference in the Further Reading section.

Hands-on Lab – Using Commands with...

Understanding the Command History

Whenever you work with the command-line, there will be times when you’ll have to enter some commands more than once. If you’ve just entered a command that’s long and complex, you may not exactly be thrilled at the prospect of having to type it in all over again. Not to worry, though. For this, bash and zsh give you the ability to recall and/or edit commands that you’ve previously entered. There are a few ways to do this.

Whenever you enter a command, it gets stored in memory until you exit the shell session. The command will then get added to a file that’s specified by the HISTFILE variable. Usually, this is the .bash_history file on bash, and the .histfile file on zsh. You’ll find these stored in each user’s home directory. To verify that, you can use the echo command, like this:

[donnie@fedora ~]$ echo $HISTFILE
/home/donnie/.bash_history
[donnie@fedora ~]$

On zsh, you’ll see this...

Escaping and Quoting

Whenever you type anything on the command-line or into a shell script, you’ll be using a mix of normal alphanumeric text and non-alphanumeric characters. Some of these characters have special meanings within the shell, and will cause the shell to perform in some special way. Sometimes, you’ll want the shell to interpret these special characters as normal text, instead of as something with a magical power. To do that, you can either escape or quote the special characters.

There are two general classes of characters that can be interpreted by the shell from within a shell command. These are:

  • Normal characters: bash and zsh interpret these characters literally. In other words, they have no special meaning to the shell.
  • Metacharacters: These characters have special meanings for bash and zsh. You could say that a metacharacter provides some sort of special instruction to these shells.

Here’s a space-separated...

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Key benefits

  • Develop portable scripts using Bash, Zsh, and PowerShell that work seamlessly across Linux, macOS, and Unix systems
  • Progress seamlessly through chapters with clear concepts, practical examples, and hands-on labs for skill development
  • Build real-world Linux administration scripts, enhancing your troubleshooting and management skills

Description

Dive into the world of Linux shell scripting with this hands-on guide. If you’re comfortable using the command line on Unix or Linux but haven’t fully explored Bash, this book is for you. It’s designed for programmers familiar with languages like Python, JavaScript, or PHP who want to make the most of shell scripting. This isn’t just another theory-heavy book—you’ll learn by doing. Each chapter builds on the last, taking you from shell basics to writing practical scripts that solve real-world problems. With nearly a hundred interactive labs, you’ll gain hands-on experience in automation, system administration, and troubleshooting. While Bash is the primary focus, you'll also get a look at Z Shell and PowerShell, expanding your skills and adaptability. From mastering command redirection and pipelines to writing scripts that work across different Unix-like systems, this book equips you for real-world Linux challenges. By the end, you'll be equipped to write efficient shell scripts that streamline your workflow and improve system automation.

Who is this book for?

This book is for programmers who use the command line on Unix and Linux servers already, but don't write primarily in Bash. This book is ideal for programmers who've been using a scripting language such as Python, JavaScript or PHP, and would like to understand and use Bash more effectively. It’s also great for beginning programmers, who want to learn programming concepts.

What you will learn

  • Grasp the concept of shells and explore their diverse types for varied system interactions
  • Master redirection, pipes, and compound commands for efficient shell operations
  • Leverage text stream filters within scripts for dynamic data manipulation
  • Harness functions and build libraries to create modular and reusable shell scripts
  • Explore the basic programming constructs that apply to all programming languages
  • Engineer portable shell scripts, ensuring compatibility across diverse platforms beyond Linux

Product Details

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Publication date, Length, Edition, Language, ISBN-13
Publication date : Oct 18, 2024
Length: 696 pages
Edition : 1st
Language : English
ISBN-13 : 9781835463574
Vendor :
Linux Foundation
Languages :
Tools :

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Product Details

Publication date : Oct 18, 2024
Length: 696 pages
Edition : 1st
Language : English
ISBN-13 : 9781835463574
Vendor :
Linux Foundation
Languages :
Tools :

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Table of Contents

25 Chapters
Getting Started with the Shell Chevron down icon Chevron up icon
Interpreting Commands Chevron down icon Chevron up icon
Understanding Variables and Pipelines Chevron down icon Chevron up icon
Understanding Input/Output Redirection Chevron down icon Chevron up icon
Customizing the Environment Chevron down icon Chevron up icon
Text-Stream Filters – Part 1 Chevron down icon Chevron up icon
Text Stream Filters – Part 2 Chevron down icon Chevron up icon
Basic Shell Script Construction Chevron down icon Chevron up icon
Filtering Text with grep, sed, and Regular Expressions Chevron down icon Chevron up icon
Understanding Functions Chevron down icon Chevron up icon
Performing Mathematical Operations Chevron down icon Chevron up icon
Automating Scripts with here Documents and expect Chevron down icon Chevron up icon
Scripting with ImageMagick Chevron down icon Chevron up icon
Using awk – Part 1 Chevron down icon Chevron up icon
Using awk – Part 2 Chevron down icon Chevron up icon
Creating User Interfaces with yad, dialog, and xdialog Chevron down icon Chevron up icon
Using Shell Script Options with getops Chevron down icon Chevron up icon
Shell Scripting for Security Professionals Chevron down icon Chevron up icon
Shell Script Portability Chevron down icon Chevron up icon
Shell Script Security Chevron down icon Chevron up icon
Debugging Shell Scripts Chevron down icon Chevron up icon
Introduction to Z Shell Scripting Chevron down icon Chevron up icon
Using PowerShell on Linux Chevron down icon Chevron up icon
Other Books You May Enjoy Chevron down icon Chevron up icon
Index Chevron down icon Chevron up icon

Customer reviews

Rating distribution
Full star icon Full star icon Full star icon Full star icon Half star icon 4.8
(4 Ratings)
5 star 75%
4 star 25%
3 star 0%
2 star 0%
1 star 0%
A. Zubarev Oct 24, 2024
Full star icon Full star icon Full star icon Full star icon Full star icon 5
This book is probably one of, if not the most, comprehensive of all on the capabilities of scripting on Linux.It covers all the common scripting shells, even PowerShell (who knew it would be possible to run Microsoft's shell on Linux?!), methods of securing scripts, text manipulation, advanced scripting techniques including automation, shell configuration, error handling, piping and much more.I especially liked the chapters on image manipulations and creating user interfaces.Be aware that this book assumes you are scripting for an on-prem resident machine and it is probably the only shortcoming I can mention.
Amazon Verified review Amazon
N/A Jan 30, 2025
Full star icon Full star icon Full star icon Full star icon Full star icon 5
Feefo Verified review Feefo
Byron Gorman Nov 15, 2024
Full star icon Full star icon Full star icon Full star icon Full star icon 5
The Ultimate Linux Shell Scripting, is an extremely fascinating read. So let’s get right to the contents of the book. First the book sets you up for success by providing you with examples of code, that you will use with the hands on labs that personally I found to be intriguing. This allows the reader to jump into the thick of Linux from the start. The labs are presented so the reader can have a better understanding of the processes and code automation, the rich contents covers everything from learning the shell and shell emulators to using Powershell on Linux and macOS. This allows the reader the opportunity to explore Linux using several different flavors. Starting with the shell you will learn simple commands that will show you the difference between the regular user and the root user. Then we step into commands and how to leverage them in your favor. By automating some Linux scripts you will be able to customize your environment and do global configurations.The book also allows you to create basic shell scripts, and filter them and the steps you through advanced scripts. This read is full of examples and illustrations that show how the script commands are used and the end result you should be seeing.At the end of each chapter there are review questions to make certain that you have maintained the correct information.If you are new to Linux, attempting to get your certification or are a seasoned Linux user this is one book to add to you’re personal Linux war chest. I added it to mine! Read more
Amazon Verified review Amazon
Emiru Mar 01, 2025
Full star icon Full star icon Full star icon Full star icon Empty star icon 4
I am giving 4 stars because i am still on chapter 2 but I love the writer's approach to the subject matter. I have been using Linux now for 10+ years and the teaching style has knowledge for every level.
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