Classic Shell Scripting [Paperback]

Arnold Robbins (Author), Nelson H.F. Beebe (Author)

Book Description

Release date: May 1, 2005

Shell scripting skills never go out of style. It's the shell that unlocks the real potential of Unix. Shell scripting is essential for Unix users and system administrators-a way to quickly harness and customize the full power of any Unix system. With shell scripts, you can combine the fundamental Unix text and file processing commands to crunch data and automate repetitive tasks. But beneath this simple promise lies a treacherous ocean of variations in Unix commands and standards. Classic Shell Scripting is written to help you reliably navigate these tricky waters.

Writing shell scripts requires more than just a knowledge of the shell language, it also requires familiarity with the individual Unix programs: why each one is there, how to use them by themselves, and in combination with the other programs. The authors are intimately familiar with the tips and tricks that can be used to create excellent scripts, as well as the traps that can make your best effort a bad shell script. With Classic Shell Scripting you'll avoid hours of wasted effort. You'll learn not only write useful shell scripts, but how to do it properly and portably.

The ability to program and customize the shell quickly, reliably, and portably to get the best out of any individual system is an important skill for anyone operating and maintaining Unix or Linux systems. Classic Shell Scripting gives you everything you need to master these essential skills.

Editorial Reviews

About the Author

Arnold Robbins, an Atlanta native, is a professional programmer and technical author. He has worked with Unix systems since 1980, when he was introduced to a PDP-11 running a version of Sixth Edition Unix. He has been a heavy AWK user since 1987, when he became involved with gawk, the GNU project's version of AWK. As a member of the POSIX 1003.2 balloting group, he helped shape the POSIX standard for AWK. He is currently the maintainer of gawk and its documentation. He is also coauthor of the sixth edition of O'Reilly's Learning the vi Editor. Since late 1997, he and his family have been living happily in Israel.

Nelson Beebe is a long time Unix user and system administrator, and has helped for years on Usenet newsgroups.

Product Details

• Paperback: 560 pages
• Publisher: O'Reilly Media; 1st edition (May 1, 2005)
• Language: English
• ISBN-10: 0596005954
• ISBN-13: 978-0596005955
• Product Dimensions: 7 x 1.1 x 9.2 inches
• Shipping Weight: 1.6 pounds (View shipping rates and policies)
• Average Customer Review: 4.6 out of 5 stars  See all reviews (17 customer reviews)
• Amazon Best Sellers Rank: #45,891 in Books (See Top 100 in Books)
  • #3 in Books > Computers & Technology > Operating Systems > Unix > Shell
  • #5 in Books > Computers & Technology > Software > Business > Utilities
  • #34 in Books > Computers & Technology > Operating Systems > Linux

Most Helpful Customer Reviews

80 of 81 people found the following review helpful

4.0 out of 5 stars Book Review: Classic Shell Scripting September 9, 2005

By Dan Clough

Format:Paperback

Classic Shell Scripting
Hidden Commands that Unlock the Power of Unix
By Arnold Robbins, Nelson H.F. Beebe
First Edition May 2005
ISBN: 0-596-00595-4
558 pages, $34.95
[...]

I found this to be quite a useful book for learning more about Unix/Linux shell scripting. I would consider this one to be an intermediate level text, and complete beginners might be better served by a more simplified book. There are quite a bit of in-depth details included, and many very nice examples and code snippets. Like all O'Reilly books, it is well organized and formatted, and clearly written.

The book opens with a brief history of Unix and how important the shell (and scripting) is to it. There are some comparisons with other programming languages, and why it is sometimes preferable to use a script versus a compiled program. The very basics of how scripts are written and used are also mentioned here, and beginners may want to refer to an additional book for more of the basic instructions.

The next few chapters cover mostly text processing with scripts, including searching, sorting, printing, extracting, and counting methods. Good examples are used, including the use of regular expressions and pipes to increase the power of your scripts. Following this, there are several chapters on more advanced scripting, including how to use variables, loops, functions, standard I/O, redirection, wildcards, using "awk", and working with external files. Extensive example code is provided throughout.

The remaining chapters of the book get into more advanced subjects such as database manipulation, process control, and increasing the security of scripts. Portability and shells other than bash are also discussed....

Perhaps the most interesting part of the book (for me) were the Appendices and other sections at the end. Appendix A is entitled "Writing Manual Pages", and is extremely informative on how to produce and format a valid man page. This is a much more complicated process than I had previously known (can you say "groff"?), and is quite interesting. For anyone who has ever complained about a poor man page, this will give you all the tools you need to write an improved version! :) Appendix B has some excellent in-depth discussion about Unix files and filesystems, including attributes and permissions. Appendix C is a summary of important Unix commands for shell scripting, categorized by function, which is a good quick reference list. Following this, there is an excellent Bibliography that recommends related books for further reading. Finally, there is good Glossary and an Index.

Overall, I found the book to be excellent in it's content and quality. I would recommend that a beginner also find a companion book to more gently introduce the fundamentals of shells and scripting, but this volume is excellent for the intermediate to advanced user. If you want to fully use the power of the Unix/Linux shell, this is a "must-have" book! Well done to the authors and O'Reilly Publishing. Read more ›

47 of 49 people found the following review helpful

5.0 out of 5 stars Practical and useful September 19, 2005

By Randy Giedrycz

Format:Paperback

Great book. The emphasis is nicely split between actually using the shell itself and the whole supporting cast of unix tools (sed, awk, cut, join, sort etc.) The idea of carefully crafting solutions using the unix toolbox mindset is key. I also like the fact he doesn't try to teach to multiple shells, but first tries to emphasize portability by sticking mainly to a POSIX standard, and only later adds info about non standard shell topics. If I could only have one book on shell scripting, this would be it. The best description is 'Practical'.

79 of 86 people found the following review helpful

5.0 out of 5 stars This might be a great second book on shell scripting. June 4, 2005

By kievite

Format:Paperback

This might be a great second book on shell scripting. Can serve as a valuable add on to "Learning Korn shell" from O'Reilly -- also a very strong book on shell scripting.

The authors provide a lot of interesting and useful information that is difficult to find in other books. They devoted Ch 5 to piping and in 5.4 "Word List" they discuss famous Doug McIlroy alternative solution to Donald Knuth program of creating the list of the n most-frequent words, with counts of their frequency of occurrence, sorted by descending count from an arbitrary text file.

The authors discuss many Unix tools that are used with shell (Unix toolbox). They provide a very good (but too brief) discussion of grep and find. Discussion of xargs (which is usually a sign on a good book on scripting) includes /dev/null trick, but unfortunately they do not mention an option -0n with which this trick makes the most sense.

One of the best chapters of the book is Ch. 13 devoted to process control. Also good is Chapter 11 that provides a solution to pretty complex and practically important for many system administrators task of merging passwd files in Unix. It provides a perfect insight into solving real sysadmins problems using AWK and shell.
Shortcomings are few. in "5.2. Structured Data for the Web" the authors should probably use AWK instead of SED. Also XML processing generally requires using a lexical analyzer, not regular expressions. Therefore a tag list example would be better converted to something simpler, for example generating C-tags for vi.

30 of 34 people found the following review helpful

5.0 out of 5 stars Invaluable resource for shell scripters June 20, 2005

By Jack D. Herrington VINE™ VOICE

Format:Paperback

This is the book that I have been waiting for years for. It's classic O'Reilly, but it's better than that. Even the O'Reilly books have fallen short of being truly useful for shell scripting. I think this was primarily because the authors have been thinking more about language fundamentals then about teaching useful things. This book is targeted towards teaching shell scripting through practical application. This is the shell scripting book to get.

15 of 18 people found the following review helpful

5.0 out of 5 stars A good intro on Unix shell scripting and the problems it solves February 16, 2007

By calvinnme HALL OF FAMETOP 500 REVIEWERVINE™ VOICE

Format:Paperback

The purpose of this handy little book is to help someone who is working with Unix through the labyrinth of tools available and learn how and when to use them. It is important to note what is mentioned in the preface - "Throughout this book, we use the term Unix to mean not only commercial variants of the original Unix system, such as Solaris, Mac OS X, and HP-UX, but also the freely available workalike systems, such as GNU/Linux and the various BSD systems: BSD/OS, NetBSD, FreeBSD, and OpenBSD." I quote the book because the word "Unix" is about as descriptive as the word "car". The intended audience is anyone who is computer literate, already knows how to program, and is regularly faced with diverse problems in the workplace that must be solved with Unix tools. This book should give you a taste of which tool to turn to and when.

This book can be divided basically into two halves. The first half is a tutorial on writing Unix scripts. The book starts with a brief history of the Unix language and the philosophy behind Unix tools. Slowly, each chapter builds up your skill at script writing. You are shown how to differentiate between shells, how to work with text extensively, how to use loops, pipelines, variables, and decision statements, and how to work with files. There are detailed example scripts at every step along the way. By the end of chapter seven, you should know enough about basic shell scripting to be dangerous.

Starting in chapter 8, you are showed more application-related information. First, Chapter 8 shows and discusses some ready-made scripts for some tasks for which there is no out-of-the-box Unix solution. Some of the handy solutions shown are for path searching and automating software builds. Chapter 9 is a crash course on awk, and is aptly named.... It is just enough to be dangerous. You learn how to solve common text processing problems with awk, but you'll need more resources to be really knowledgable. Chapter 10 explains the usage of common commands for listing files, modifying their timestamps, creating temporary files, finding files in a directory hierarchy, applying commands to a list of files, determining the amount of filesystem space used, and comparing files. Next there are two applied chapters showing you how to merge several databases and how to perform spellchecking by using scripting. Chapter 13 changes the subject a bit and talks about the concept of processes in Unix and how you can use their statistics to accomplish a number of monitoring and control tasks. Chapter 14 talks about problems you may run into if you try to take advantage of shell-language extensions, while Chapter 15 addresses the issue of writing secure scripts to the extent it is possible to do so. Writing man pages, and the basics of the Unix filesystem are the subjects of the last two chapters of the book.

I would say it is a good modern introduction to the subject of shell scripting and Unix tools and how to use them. It doesn't dive deeply into any particular topic, but it will get you started by broadly introducing you to the problems most Unix script writers and system admins face regularly and how to get started solving those problems. I highly recommend it for that purpose. Read more ›