tailieunhanh - Linux Shell Scripting Cookbook

This book is written in cookbook style and it offers learning through recipes with examples and illustrations. Each recipe contains step-by-step instructions about everything necessary to execute a particular task. The book is designed so that you can read it from start to end for beginner's or just open up any chapter and start following the recipes as a reference for advanced users. If you are a beginner or an intermediate user who wants to master the skill of quickly writing scripts to perform various tasks without reading the entire man pages, this book is for you. You can start. | Linux Shell Scripting Cookbook Solve real-world shell scripting problems with over 110 simple but incredibly effective recipes Sarath Lakshman rPACKTI Pen source community experience distilled PUBLISHING BIRMINGHAM-MUMBAI Linux Shell Scripting Cookbook Copyright 2011 Packt Publishing All rights reserved. No part of this book may be reproduced stored in a retrieval system or transmitted in any form or by any means without the prior written permission of the publisher except in the case of brief quotations embedded in critical articles or reviews. Every effort has been made in the preparation of this book to ensure the accuracy of the information presented. However the information contained in this book is sold without warranty either express or implied. Neither the author nor Packt Publishing and its dealers and distributors will be held liable for any damages caused or alleged to be caused directly or indirectly by this book. Packt Publishing has endeavored to provide trademark information about all of the companies and products mentioned in this book by the appropriate use of capitals. However Packt Publishing cannot guarantee the accuracy of this information. First published January 2011 Production Reference 1200111 Published by Packt Publishing Ltd. 32 Lincoln Road Olton Birmingham B27 6PA UK. ISBN 978-1-849513-76-0 Cover Image by Charwak A charwak8 6@ Table of Contents Preface 1 Chapter 1 Shell Something Out 7 Introduction 7 Printing in the terminal 9 Playing with variables and environment variables 12 Doing math calculations with the shell 17 Playing with file descriptors and redirection 19 Arrays and associative arrays 25 Visiting aliases 27 Grabbing information about terminal 29 Getting setting dates and delays 30 Debugging the script 33 Functions and arguments 35 Reading the output of a sequence of commands 38 Reading n characters without pressing Return 40 Field separators and iterators 41 Comparisons and tests 44 Chapter 2 Have a