Book Image

Linux Shell Scripting Cookbook, Second Edition - Second Edition

Book Image

Linux Shell Scripting Cookbook, Second Edition - Second Edition

Overview of this book

The shell remains one of the most powerful tools on a computer system — yet a large number of users are unaware of how much one can accomplish with it. Using a combination of simple commands, we will see how to solve complex problems in day to day computer usage.Linux Shell Scripting Cookbook, Second Edition will take you through useful real-world recipes designed to make your daily life easy when working with the shell. The book shows the reader how to effectively use the shell to accomplish complex tasks with ease.The book discusses basics of using the shell, general commands and proceeds to show the reader how to use them to perform complex tasks with ease.Starting with the basics of the shell, we will learn simple commands with their usages allowing us to perform operations on files of different kind. The book then proceeds to explain text processing, web interaction and concludes with backups, monitoring and other sysadmin tasks.Linux Shell Scripting Cookbook, Second Edition serves as an excellent guide to solving day to day problems using the shell and few powerful commands together to create solutions.
Table of Contents (16 chapters)
Linux Shell Scripting Cookbook
Credits
About the Authors
About the Reviewers
www.PacktPub.com
Preface
Index

Slicing filenames based on extension


Several shell scripts perform manipulations based on filenames. We may need to perform actions such as renaming the files by preserving the extension, converting files from one format to another (change the extension by preserving the name), extracting a portion of the filename, and so on. The shell comes with inbuilt features for slicing filenames based on different conditions. Let us see how to do it.

How to do it…

The name from name.extension can be easily extracted using the % operator. You can extract the name from "sample.jpg" as follows:

file_jpg="sample.jpg"
name=${file_jpg%.*}
echo File name is: $name

The output is:

File name is: sample

The next task is to extract the extension of a file from its filename. The extension can be extracted using the # operator as follows:

Extract .jpg from the filename stored in the variable file_jpg as follows:

extension=${file_jpg#*.}
echo Extension is: jpg

The output is:

Extension is: jpg

How it works…

In the first task...