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

Creating filesystems with compression


squashfs is a heavy-compression based read-only filesystem that is capable of compressing 2 to 3 GB of data onto a 700 MB file. If you have ever used a Linux LiveCD (or LiveUSB), they are built using squashfs . These CDs make use of a read-only compressed filesystem which keeps the root filesystem on a compressed file. It can be loopback mounted and loads a complete Linux environment. Thus, when some files are required by processes, they are decompressed and loaded onto the RAM and used.

squashfs can be useful when it is required to keep files heavily compressed and to access a few of them without extracting all the files. This is because completely extracting a large compressed archive takes a long time. However, if an archive is loopback mounted, it will be very fast since only the required portion of the compressed archive is decompressed when requested. Let's see how we can use squashfs.

Getting ready

squashfs internally uses compression algorithms...