El Arte De Programar En Unix

The Art of Unix Programming
by Eric Steven Raymond

The Art of Unix Programming
by Eric Steven Raymond Copyright © 2003 Eric S. Raymond
This book and its on-line version are distributed under the terms of the Creative Commons Attribution-NoDerivs 1.0 license, with the additional proviso that the right to publish it on paper for sale or other for-profit use is reserved to Pearson Education,Inc. A reference copy of this license may be found at http://creativecommons.org/licenses/by-nd/1.0/legalcode. AIX, AS/400, DB/2, OS/2, System/360, MVS, VM/CMS, and IBM PC are trademarks of IBM. Alpha, DEC, VAX, HP-UX, PDP, TOPS-10, TOPS-20, VMS, and VT-100 are trademarks of Compaq. Amiga and AmigaOS are trademarks of Amiga, Inc. Apple, Macintosh, MacOS, Newton, OpenDoc, and OpenStep are trademarksof Apple Computers, Inc. ClearCase is a trademark of Rational Software, Inc. Ethernet is a trademark of 3COM, Inc. Excel, MS-DOS, Microsoft Windows and PowerPoint are trademarks of Microsoft, Inc. Java. J2EE, JavaScript, NeWS, and Solaris are trademarks of Sun Microsystems. SPARC is a trademark of SPARC international. Informix is a trademark of Informix software. Itanium is a trademark of Intel.Linux is a trademark of Linus Torvalds. Netscape is a trademark of AOL. PDF and PostScript are trademarks of Adobe, Inc. UNIX is a trademark of The Open Group. The photograph of Ken and Dennis in Chapter 2 appears courtesy of Bell Labs/Lucent Technologies. The epigraph on the Portability chapter is from the Bell System Technical Journal, v57 #6 part 2 (July-Aug. 1978) pp. 2021-2048 and isreproduced with the permission of Bell Labs/Lucent Technologies.

Dedication
To Ken Thompson and Dennis Ritchie, because you inspired me.

i

Table of Contents
Preface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xvi Who Should Read This Book . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . xvii How to Use This Book . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xviii Related References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xix Conventions Used in This Book . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . xx Our Case Studies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xxi Author’s Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xxii I. Context . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . 24 1. Philosophy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 Culture? What Culture? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 The Durability of Unix . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . 25 The Case against Learning Unix Culture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 What Unix Gets Wrong . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 What Unix Gets Right . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 Open-Source Software .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 Cross-Platform Portability and Open Standards . . . . . . . . . . . . . . . . . . . . . 29 The Internet and the World Wide Web . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 The Open-Source Community . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 Flexibility All the...