Browse Books

Reviewer: Allan M. Stavely

When I first saw the title of this book, I said to myself Are they kidding__?__ AWK is just one of those handy Unix tools for making simple data filters. I suppose its notation can be considered a language, but is it not a gross overstatement to call it a programming language__?__ Well, no. Actually, AWK has every right to be called a programming language. It has such things as variables, including arrays; floating-point arithmetic, including transcendental functions; all the control constructs of the C language; and formatted output. The most recent version even allows users to define their own functions. If a programmer uses all of these features, an AWK program looks almost like a C program. AWK's greatest strength, though, is still that it is easy to write very small and concise programs for data manipulation—reading input lines, breaking them into fields or classifying them by pattern-matching, performing simple transformations, and writing corresponding output lines. It is ideally suited for producing quick-and-dirty implementations that can be used once and discarded or that can be used as prototypes for larger-scale, more efficient implementations. The book is quite clear and pleasant to read. Chapter 1 is a tutorial, chapter 2 is the reference manual, and the remaining chapters illustrate the use of AWK in various applications. Titles of these chapters are “Data Processing,” “Reports and Databases,” “Processing Words,” “Little Languages,” and “Experiments with Algorithms.” The examples demonstrate the wide applicability of AWK and illustrate a variety of programming techniques. A possible criticism of the book might be that to explain a language as simple as AWK, you do not need a 210-page book. Indeed, the first two chapters occupy only 66 pages. But it would be a shame to do without the examples. Besides being quite clever in places, they give you a ready-made collection of lots of useful programs that you can adapt to your own needs. Chapters 3 through 7 are almost completely independent of each other, and you may browse through them according to your interests and needs. I enjoyed the book, and I recommend it.