Mastering Linux Shell Scripting

Key Features

• Identify the high level steps such as verifying user input, using command lines and conditional statements in creating and executing simple shell scripts
• Create and edit dynamic shell scripts to manage complex and repetitive tasks
• Learn about scripting in Perl and programming in Python as a BASH scripting alternative with this practical, step-by-step guide

Book Description

Shell scripting is a quick method to prototype a complex application or a problem by automating tasks when working on Linux-based systems. Using both simple one-line commands and command sequences complex problems can be solved with ease, from text processing to backing up sysadmin tools.

In this book, you'll discover everything you need to know to master shell scripting and make informed choices about the elements you employ. 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. Implement functions and edit files using the Stream Editor, script in Perl, program in Python – as well as complete coverage of other scripting languages to ensure you can choose the best tool for your project.

What you will learn

• Use the type command to identify the order of command evaluation
• 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 Perl and Python with BASH

About the Author

Andrew Mallett is the owner of The Urban Penguin and is a comprehensive provider for professional Linux software development, training, and services. Having always been a command-line fan, he feels that so much time can be saved through knowing command-line shortcuts and scripting. TheUrbanPenguin YouTube channel, maintained by Andrew, has well over 800 videos to support this and he has authored four other Packt titles.

Table of Contents

1. What and Why of Scripting with Bash
2. Creating Interactive Scripts
3. Conditions Attached
4. Creating Code Snippets
5. Alternative Syntax
6. Iterating with Loops
7. Creating Building Blocks with Functions
8. Introducing sed
9. Automating Apache Virtual Hosts
10. Awk Fundamentals
11. Summarizing Logs with Awk
12. A Better lastlog with Awk
13. Using Perl as a Bash Scripting Alternative
14. Using Python as a Bash Scripting Alternative