Linux Shell Scripting Essentials

Book excerpt: Learn shell scripting to solve complex shell-related problems and to efficiently automate your day-to-day tasks About This Book Familiarize yourself with the terminal by learning about powerful shell features Automate tasks by writing shell scripts for repetitive work Packed with easy-to-follow, hands-on examples to help you write any type of shell script with confidence Who This Book Is For This book is aimed at administrators and those who have a basic knowledge of shell scripting and who want to learn how to get the most out of writing shell scripts. What You Will Learn Write effective shell scripts easily Perform search operations and manipulate large text data with a single shell command Modularize reusable shell scripts by creating shell libraries Redirect input, output, and errors of a command or script execution to other streams Debug code with different shell debugging techniques to make your scripts bug-free Manage processes, along with the environment variables needed to execute them properly Execute and embed other languages in your scripts Manage creation, deletion, and search operations in files In Detail Shell scripting is a quick method to prototype complex applications or problems. Shell scripts are a collection of commands to automate tasks, usually those for which the user has a repeated need, when working on Linux-based systems. Using simple commands or a combination of them in a shell can solve complex problems easily. This book starts with the basics, including essential commands that can be executed on Linux systems to perform tasks within a few nanoseconds. You'll learn to use outputs from commands and transform them to show the data you require. Discover how to write shell scripts easily, execute script files, debug, and handle errors. Next, you'll explore environment variables in shell programming and learn how to customize them and add a new environment. Finally, the book walks you through processes and how these interact with your shell scripts, along with how to use scripts to automate tasks and how to embed other languages and execute them. Style and approach This book is a pragmatic guide to writing efficient shell programs, complete with hands-on examples and tips.