Preface

This book focuses on Perl usage from the command line, similar to grep, sed and awk usage. Syntax and features of these tools (along with languages like C and bash) were inspirations for Perl, so prior experience with them would make it easier to learn Perl.

You'll learn about various command line options and Perl features that make it possible to write compact cli scripts. Learning to use Perl from the command line will also allow you to construct solutions where Perl is just another tool in the shell ecosystem.

Prerequisites

You should be comfortable with programming basics and have prior experience working with Perl. You should know concepts like scalar, array, hash and special variables, be familiar with control structures, regular expressions etc. If you need resources to get started with Perl and regular expressions, you can start with these links:

You should also have prior experience working with command line, bash shell and be familiar with concepts like file redirection, command pipeline and so on.

Conventions

  • The examples presented here have been tested with Perl version 5.32.0 and includes features not available in earlier versions.
  • Code snippets shown are copy pasted from bash shell and modified for presentation purposes. Some commands are preceded by comments to provide context and explanations. Blank lines have been added to improve readability, only real time is shown for speed comparisons and so on.
  • Unless otherwise noted, all examples and explanations are meant for ASCII characters
  • External links are provided for further reading throughout the book. Not necessary to immediately visit them. They have been chosen with care and would help, especially during re-reads.
  • The learn_perl_oneliners repo has all the code snippets and files used in examples and exercises and other details related to the book. If you are not familiar with git command, click the Code button on the webpage to get the files.

Acknowledgements

A heartfelt thanks to all my readers. Your valuable support has significantly eased my financial concerns and allows me to continue writing books.

Feedback and Errata

I would highly appreciate if you'd let me know how you felt about this book, it would help to improve this book as well as my future attempts. Also, please do let me know if you spot any error or typo.

Issue Manager: https://github.com/learnbyexample/learn_perl_oneliners/issues

E-mail: learnbyexample.net@gmail.com

Twitter: https://twitter.com/learn_byexample

Author info

Sundeep Agarwal is a freelance trainer, author and mentor. His previous experience includes working as a Design Engineer at Analog Devices for more than 5 years. You can find his other works, primarily focused on Linux command line, text processing, scripting languages and curated lists, at https://github.com/learnbyexample. He has also been a technical reviewer for Command Line Fundamentals book and video course published by Packt.

List of books: https://learnbyexample.github.io/books/

License

This work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License

Code snippets are available under MIT License

Resources mentioned in Acknowledgements section above are available under original licenses.

Book version

1.5

See Version_changes.md to track changes across book versions.