Product Description

sed & awk describes two text processing programs that are mainstays of the UNIX programmer's toolbox. sed is a "stream editor" for editing streams of text that might be too large to edit as a single file, or that might be generated on the fly as part of a larger data processing step. The most common operation done with sed is substitution, replacing one block of text with another. awk is a complete programming language. Unlike many conventional languages, awk is "data driven" -- you specify what kind of data you are interested in and the operations to be performed when that data is found. awk does many things for you, including automatically opening and closing data files, reading records, breaking the records up into fields, and counting the records. While awk provides the features of most conventional programming languages, it also includes some unconventional features, such as extended regular expression matching and associative arrays. sed & awk describes both programs in detail and includes a chapter of example sed and awk scripts. This edition covers features of sed and awk that are mandated by the POSIX standard. This most notably affects awk, where POSIX standardized a new variable, CONVFMT, and new functions, toupper() and tolower(). The CONVFMT variable specifies the conversion format to use when converting numbers to strings (awk used to use OFMT for this purpose). The toupper() and tolower() functions each take a (presumably mixed case) string argument and return a new version of the string with all letters translated to the corresponding case. In addition, this edition covers GNU sed, newly available since the first edition. It also updates the first edition coverage of Bell Labs nawk and GNU awk (gawk), covers mawk, an additional freely available implementation of awk, and briefly discusses three commercial versions of awk, MKS awk, Thompson Automation awk (tawk), and Videosoft (VSAwk).

Product Details

• Amazon Sales Rank: #104639 in Books
• Published on: 1997-03-01
• Original language: English
• Number of items: 1
• Binding: Paperback
• 432 pages

From the Publisher
sed & awk describes two text manipulation programs that are mainstays of the UNIX programmer's toolbox. This edition covers the sed and awk programs as they are mandated by the POSIX standard and includes discussion of the GNU versions of these programs.

About the Author
Dale Dougherty is the publisher of the O'Reilly Network and Director of O'Reilly Research. Dale has been instrumental in many of O'Reilly's most important efforts, including founding O'Reilly & Associates with Tim O'Reilly. He was the developer and publisher of Global Network Navigator (GNN), the first commercial Web site. Dale was developer and publisher of Web Review, the online magazine for Web designers, and he was O'Reilly & Associates' first editor. Dale has written and edited numerous books at O'Reilly & Associates. Dougherty is a Lecturer in the School of Information Management and Systems (SIMS) at the University of California at Berkeley.

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.

Customer Reviews

really excellent cant praise it enough!
I purchased this book over a year ago now when I was doing a shell scripting course at university and couldnt understand a thing the lecturer was saying! This book took me out of the hole I was in and passed me the course, no doubt about it.

As if that werent enough, I have recently undertaken the LPIC1 certification and again this book was worth its weight in gold. I was studying basic use of sed in the certification guide and deicded to brush up on regular expressions and the use of sed and again, out came this book and again, within a few hours it was all made clear.

There is a large chapter on regular expressions thrown in so there's no need to buy a separate book on those unless your going in heavy, the material taught in this book is advanced enough for all but the most masochistic of people!

Thoroughly good read very impressive book. Well worth the money. Its one of the most satisfying feelings when you finally crack a regexp and get the sed script to spit out what you need!

Indispensible tools for text manipulation
Unix has earned itself quite a reputation for its potent tools, used for batch editing of text files (like program output). Sed and Awk are two of these tools. Sed is a direct descendent of Ed, the original Unix line editor, which employs regular expressions, a powerful method for description of patterns in text, for operations like substitute, append or delete. Awk is a complete scripting language with programming structures like conditionals, loops, functions etc., developed in 1970's by Alfred Aho, Brian Kernighan and Peter Weinberger (hence A-W-K). The trio has also written a book on Awk.

Dale Dougherty (in the 2nd edition with Arnold Robbins, maintainer of GNU Awk and author of several more books on Awk programming language) have made a good job in making a thoroughly readable tutorial on Sed and Awk. However, it remains a mystery to me how they succeeded to fill no less than 407 pages with it. Mind you, Sed and Awk are not really some big monsters. There exist something like two dozens of operators in Sed (most of them you will probably never use), and the syntax of Awk mimics those of C programming language, so it is likely that you know it already. Once you grok the idea of regular expressions, you should become a proficient user of Awk in about 30 minutes.

In conclusion, go buy the book if your need to manipulate text files on Unix and you think you need a lengthy tutorial with a gentle learning curve. Otherwise, short references on Awk and Sed, like the ones in Unix Power Tools and a bunch of examples showing some tricks you might not think of, will probably be more useful. In addition, it is good to know that during the nineties, much of the focus has drifted from Awk to Perl, so you might consider a book on Perl as well.

A gentle guide to two daunting tools.
Sed & Awk are two of the most hostile looking Unix utilities. Although I was an experienced shell scripter I was terrified of Sed & Awk until I got this book. It's an excellently written guide, starting very simply without being too basic and working up to some complex concepts.

I use sed/awk daily now, they're extremely useful tools.

If this make VERY heavy use of these tools I'd also recommend reading another O'Reilly book - "Mastering Regular Expressions"