Mercury Learning and Information & Oswald Campesato 
WORKING WITH grep, sed, AND awk Pocket Primer [EPUB ebook] 
A Quick Guide to Mastering Powerful Command Line Tools

This book introduces readers to three powerful command-line utilities—grep, sed, and awk—that can create simple yet powerful shell scripts. Using the bash shell, it focuses on small text files to help readers understand these tools. Grep searches for patterns in data, sed modifies data, and awk performs tasks on pattern matches. Aimed at those new to the bash environment, the book is also valuable for those with some experience.
The journey starts with grep, teaching how to search for specific words or patterns in data. It then moves to sed, showing how to change or modify data efficiently. Finally, it delves into awk, a versatile programming language for searching and processing data files. The book also includes a chapter on using regular expressions with these tools, enhancing your scripting capabilities.
Mastering these utilities is crucial for efficient data handling and automation in a bash environment. This book transitions readers from basic to advanced command-line skills, blending theory with practical examples. It is an essential resource for anyone looking to harness the full power of bash scripting.