Egresado Ingnieria En Telecomunicaciones

bash Cookbook

™manual de linux

Carl Albing, JP Vossen, and Cameron Newham

Beijing • Cambridge • Farnham • Köln • Paris • Sebastopol • Taipei • Tokyo

bash Cookbook™
by Carl Albing, JP Vossen, and Cameron Newham
Copyright © 2007 O’Reilly Media, Inc. All rights reserved. Printed in the United States of America. Published by O’Reilly Media, Inc., 1005 Gravenstein Highway North,Sebastopol, CA 95472. O’Reilly books may be purchased for educational, business, or sales promotional use. Online editions are also available for most titles (safari.oreilly.com). For more information, contact our corporate/institutional sales department: (800) 998-9938 or corporate@oreilly.com.

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This book uses RepKover™ a durable and flexible lay-flat binding. , ISBN 10: 0-596-52678-4 ISNB 13: 978-0-596-52678-8 [M]

Table of Contents

Preface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xiii1. Beginning bash . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 1.10 1.11 1.12 1.13 1.14 1.15 1.16 Decoding the Prompt Showing Where You Are Finding and Running Commands Getting Information About Files Showing All Hidden (dot) Files in the Current Directory Using Shell Quoting Using or ReplacingBuilt-ins and External Commands Determining If You Are Running Interactively Setting bash As Your Default Shell Getting bash for Linux Getting bash for xBSD Getting bash for Mac OS X Getting bash for Unix Getting bash for Windows Getting bash Without Getting bash Learning More About bash Documentation 4 5 6 8 10 12 13 15 16 17 20 21 22 23 24 25

2. Standard Output . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
2.1 2.2 2.3 2.4 2.5 2.6 Writing Output to the Terminal/Window Writing Output but Preserving Spacing Writing Output with More Formatting Control Writing Output Without the Newline Saving Output from a Command Saving Output to Other Files 29 30 31 32 33 34

iii

2.7 2.8 2.9 2.10 2.11 2.12 2.13 2.14 2.15 2.16 2.17 2.18 2.19 2.202.21 2.22

Saving Output from the ls Command Sending Both Output and Error Messages to Different Files Sending Both Output and Error Messages to the Same File Appending Rather Than Clobbering Output Using Just the Beginning or End of a File Skipping a Header in a File Throwing Output Away Saving or Grouping Output from Several Commands Connecting Two Programs by Using Output As Input Saving aCopy of Output Even While Using It As Input Connecting Two Programs by Using Output As Arguments Using Multiple Redirects on One Line Saving Output When Redirect Doesn’t Seem to Work Swapping STDERR and STDOUT Keeping Files Safe from Accidental Overwriting Clobbering a File on Purpose

35 37 37 39 39 40 41 41 43 44 46 47 48 50 52 53

3. Standard Input . . . . . . . . . . . . . . . . . . . . . ....