Book Image

Linux Shell Scripting Cookbook

By : Sarath Lakshman
Book Image

Linux Shell Scripting Cookbook

By: Sarath Lakshman

Overview of this book

<p>GNU/Linux is a remarkable operating system that comes with a complete development environment that is stable, reliable, and extremely powerful. The shell being the native interface to communicate with the operating system is capable of controlling the entire operating system. There are numerous commands on Linux shell which are documented but hard to understand. The man pages are helpful but they are very lengthy and it does not give any clues on key areas where commands can be used. Proper usage of shell commands can easily solve many complex tasks with a few lines of code, but most linux users don't have the right know-how to use the Linux shell to its full potential.<br /><br />Linux Shell Scripting Cookbook is a collection of essential command-line recipes along with detailed descriptions tuned with practical applications. It covers most of the commands on Linux with a variety of usecases accompanied by plenty of examples. This book helps you to perform complex data manipulations involving tasks such as text processing, file management, backups and more with the combination of few commands.<br /><br />Linux Shell Scripting Cookbook shows you how to capitalize on all the aspects of Linux using the shell scripting language. This book teaches you how to use commands to perform simple tasks all the way to scripting complex tasks such as managing large amounts of data on a network.</p> <p>It guides you on implementing some of the most common commands in Linux with recipes that handle any of the operations or properties related with files like searching and mining inside a file with grep. It also shows you how utilities such as sed, awk, grep, cut can be combined to solve text processing related problems. The focus is on saving time by automating many activities that we perform interactively through as browser with a few lines of script.</p> <p>This book will take you from a clear problem description to a fully functional program. The recipes contained within the chapter will introduce the reader to specific problems and provide hands-on solutions.</p>
Table of Contents (16 chapters)
Linux Shell Scripting Cookbook
Credits
About the Author
About the Reviewers
www.PacktPub.com
Preface
Index

Backup snapshots with rsync


Backing up data is something that most sysadmins need to do regularly. We may need to backup data in a web server or from remote locations. rsync is a command that can be used to synchronize files and directories from one location to another while minimizing data transfer using file difference calculations and compression. The advantage of rsync over the cp command is that rsync uses strong difference algorithms. Also, it supports data transfer across networks. While making copies, it compares the files in the original and destination locations and will only copy the files that are newer. It also supports compression, encryption, and a lot more. Let's see how we can work with rsync.

How to do it...

In order to copy a source directory to a destination (to create a mirror) use:

$ rsync -av source_path destination_path

In this command:

  • -a stands for archiving

  • -v (verbose) prints the details or progress on stdout

The above command will recursively copy all the files...