Mastering Linux Shell Scripting - Second Edition

<Mastering Linux Shell Scripting - Second Edition> ▶Book Description
In this book, you'll discover everything you need to know to master shell scripting and make informed choices about the elements you employ.

Grab your favorite editor and start writing your best Bash scripts step by step. Get to grips with the fundamentals of creating and running a script in normal mode, and in debug mode. Learn about various conditional statements' code snippets, and realize the power of repetition and loops in your shell script. You will also learn to write complex shell scripts. This book will also deep dive into file system administration, directories, and system administration like networking, process management, user authentications, and package installation and regular expressions. Towards the end of the book, you will learn how to use Python as a BASH Scripting alternative.

By the end of this book, you will know shell scripts at the snap of your fingers and will be able to automate and communicate with your system with keyboard expressions.

▶What You Will Learn
⦁ Make, execute, and debug your first Bash script
⦁ Create interactive scripts that prompt for user input
⦁ Foster menu structures for operators with little command-line experience
⦁ Develop scripts that dynamically edit web configuration files to produce a new virtual host
⦁ Write scripts that use AWK to search and reports on log files
⦁ Draft effective scripts using functions as building blocks, reducing maintenance and build time
⦁ Make informed choices by comparing different script languages such as Python with BASH

▶Key Features
⦁ Identify high-level steps such as verifying user input
⦁ Using the command line and conditional statements in creating/executing simple shell scripts
⦁ Create and edit dynamic shell scripts to manage complex and repetitive tasks
⦁ Leverage the command-line to bypass GUI and automate common tasks

▶Who This Book Is For
If you are a Linux administrator or a system administrator and are interested in automating tasks in your daily lives, saving time and effort, this book is for you. Basic shell scripting and command-line experience will be required. Familiarity with the tasks you need to automate will be helpful.

▶What this book covers
⦁ Chapter 1, The What and Why of Scripting with Bash, will introduce Linux shells, how to write your first shell script, how to prepare your editor, how to debug your shell script, and some basic bash programming, such as declaring variables, variable scope, and command substitution.
⦁ Chapter 2, Creating Interactive Scripts, covers how to read input from the user using read command, how to pass options to your script, how to control the visibility of the entered text, and how to limit the number of entered characters.
⦁ Chapter 3, Conditions Attached, will introduce the if statement, the case statement, and other testing command such as else and elif.
⦁ Chapter 4, Creating Code Snippets, covers creating and using code snippets using editors, such as vim and Visual Studio Code.
⦁ Chapter 5, Alternative Syntax, will discuss advanced testing using [[ and how to perform arithmetic operations.
⦁ Chapter 6, Iterating with Loops, will teach you how to use for loops, while loops, and until loops to iterate over simple values and complex values.
⦁ Chapter 7, Creating Building Blocks with Functions, will introduce functions and explains how to create a function, list builtin functions, pass parameters to functions, and writing recursive functions.
⦁ Chapter 8, Introducing the Stream Editor, will introduce the basics of sed tool to manipulate files, such as adding, replacing deleting, and transforming text.
⦁ Chapter 9, Automating Apache Virtual Hosts, contains a practical example of sed and explains how to create virtual hosts automatically using sed.
⦁ Chapter 10, AWK Fundamentals, will discuss AWK and how to filter file content using it. Also, we will discuss some AWK programming basics.
⦁ Chapter 11, Regular Expressions, covers regular expressions, their engines, and how to use them with sed and AWK to empower your script.
⦁ Chapter 12, Summarizing Logs with AWK, will show how to process the httpd.conf Apache log file using AWK and extract useful well-formatted data.
⦁ Chapter 13, A Better lastlog with AWK, will show you how to use AWK to output beautiful reports using the lastlog command by filtering and processing the lastlog output.
⦁ Chapter 14, Using Python as a Bash Scripting Alternative, will discuss Python programming language basics and explains how to write some Python scripts as a bash script alternative.