Media praise for Mastering Regular Expressions

"Jeffrey Freidl's book is not a dummies guide; it demands concentration, but it is a good read in its own right. Even though it is intended for programmers working with regex-supported languages and programming environments, it is a valuable resource for informed lay-readers who would like to explore this fascinating field. As the only reference to the art, it should be on the bookshelf of every programmer and anyone who works with large text files."--Major Keary, Book News, 2002 No 5

"Mastering Regular Expressions by Jeffrey Friedl is quite possibly the best programming book I have ever been fortunate enough to read. A straight forward style, combined with an uncanny ability to make sense of what can be a very confusing subject, all combined with the power of getting control of regular expressions make this book a must buy, Covering regular expressions in such a comprehensible way makes this book a must buy all by it's self, but coupling that with the keen insights and real world examples used for Perl and other programming give this book a permanent place on my desktop." --Wes Ritchey, The Internet Eye Magazine, Dec 2000

"The definitive work on regular expressions is Mastering Regular Expressions by Jeffrey E. F. Friedl. For those who want to get the most out of working with regular expressions, I highly recommend this book." --Brad Merrill, January 2001

"This book is a masterpiece-one I would highly recommend for your technical library, especially if you write Perl Scripts."-Gene Wilburn, Computer Paper, June 2000

"I very much enjoyed reading this book, and certainly learned a lot, even about Perl." --Tom Christiansen, co-author of Programming Perl

"Mastering Regular Expressions" is destined to be a classic reference on the subject it covers. If you're just getting started with regex, this book will save you a lot of time (and grief). If you are already using regex, it will help you extend your ability and understanding." --Dr. Dobbs, December 1997

"And you thought you were a regular expression guru, eh? Prepare to be humbled! Jeffrey Friedl will show you just how little you knew about regex's...even when you thought you knew it all. What may initially appear to be a dry subject becomes absolutely fascinating with his sometimes humorous (but always accurate) writing style.... Decorum prevented me from saying what I really thought: I hate your book! It continues to expose my utter ignorance on a subject about which I previously thought I had a clue." -- Bob Nelson, Dallas, TX

"Mastering Regular Expressions is very instructive and (surprisingly, to me, a professor of literature) a lot of fun. I'm reading it straight through, as you suggest, and finding it to be very entertaining." --Richard Shroyer, Research Director and Professor of English, Univ. of Western Ontario, London, Ontario, Canada

"The book has been really helpful. I was always scared of regular expressions before and wrote a lot of extra code to get around using them. Now, I try to find a way to use regular expressions to solve every problem." --Roman Milner

"Master Regular Expressions is a superior book. Author Jeffrey Friedl has produces a current, well-written, precise addition to the O'Reilly repertoire, with a volume completely devoted to text and data manipulation. It provides the perfect complement to CGI and Delphi programs and their accompanying texts.... I highly recommend it for anyone and everyone involved with regular expression manipulation." --Sys Admin, April 1997

"This book is important because regex is so intimidating, and Freidl make it much easier to understand. Many programmers don't use the regex available in their development tools. Chances are, regex will save you a lot of time when you find yourself stuck with a pile of someone else's source code that you need to maintain. If you're just getting started with regex, this book will save you a lot of time (and grief). If you are already using regex, you will extend your ability and understanding." --Dr. Dobbs Journal

"Many thanks, and renewed compliments on your wonderful books; I saw
Mastering Regular Expressions in Melbourne, Australia, and could hardly restrain myself from buying it there and then (at great financial punishment; books in Australia cost bags of gold; I waited, and bought it at the bookstore on the Apple Computer campus as soon as I got back). What a nifty book. I hope I can use that in a course some time, too." -- Professor Geoffrey K. Pullum, Stevenson College, UCSC, Santa Cruz, CA

"A stupendous tour de force of all aspects of pattern matching. With an impeccable eye to the tiniest significant detail, the author covers topics ranging from the subtle differences among NFA, DFA, and POSIX NFA matching behaviors to the practical distinctions of how varying versions of grep, sed, awk, emacs, tcl, python, and perl behave. The author at all times connects theory to practical application of this knowledge in daily programming." --Tom Christiansen, Camel Critiques

"Novice DOS users tend to find out reasonably quickly that "*.*", when used as an argument with the delete command, means "everything". Intermediate users will have found that "?????.exe" matches programs with filenames under six characters long, and that "*." finds directories (since novices usually don't give directory names extensions). Advanced users know that if you want to find a file which has "LAN" somewhere in the name you need to use "?????LAN?????.*". DOS wildcards, though, are only the crudest approximation to the power of the algorithmic matching that can be done with regular expressions used in UNIX and UNIX derived applications. "As the author points out, documentation on regular expressions is abundant, but not very good. In addition, there are differences between the use of regular expressions in different applications and different versions of the same application. "Friedl provides a realistic, reliable, and very readable introduction and overview of the topic. The use of humour not only leavens the text, but supports the concepts being addressed. The material is comprehensive, and covers differences in the use of regular expressions both in sections dealing with specific functions, and in a separate chapter which details usage in awk, Tcl, and emacs. (Perl gets a chapter all to itself.) Readers may pursue the topic as they wish, of course, but Friedl's offer of mastery extends to a chapter on *how* matching is done: the internals of regular expressions. "Definitely, a valuable addition to the UNIX bookshelf, and also of use to those working with grep, awk, Perl and the like on other platforms." --copyright Robert M. Slade, 1997

"In the forties, Warren McCulluch and Walter Pitts created neuron-level models of how the nervous system operates. The mathematician, Stephen Kleene, later described these models using his mathematical notation called regular expressions. Ken Thompson incorporated that system of notation into qed (the IBM 7094 grandfather of the UNIX ed) and eventually into grep. Ever since that time, regular expressions have constantly seeped into UNIX and UNIX-like utilities. These are the regular expressions that are not used to explain nerves; these are ones used to get on them.

"Grep, egrep, vi, sed, lex, awk, emacs, Perl, Tcl, and Python support regular expressions. In fact, regular expressions (regexes) are an essential part of these utilities. Unfortunately, regexes usually don't seem very important in the documentation. Man pages only casually mention regexes with usually no theoretical explanation and very limited practical discussion. This leaves most of us crafting regexes like we're playing the board game Battleship -- keep guessing until we sink a solution.

"Mastering Regular Expressions is an important work about an often overlooked concept that permeates UNIX: the regular expression. It is clear and practical. The regular expression is explained by concept and not by rote. Friedl is trying to get us to think in regular expressions and not to blindly parrot (or pirate) his examples.

"The book uses quick do-you-really-understand questions at key spots in the text. The book is constructed so that you have to turn the current page to see the answer to a question. Unfortunately, this prevents the 'accidental' hint. Be honest. It's human nature to have wondering eyes when a question is too hard. If you can't answer a question in this book, then you know for a fact that you can't answer it. It's too hard to 'accidentally' turn a page.

"That's only one example of its thoughtful design. The typography is the best use of typography as a communication tool that I have seen. With code snippets like 'if ($input=~m/^([-+]?[0-9]+(\.[0-9]*)?)([CF])$/)', the typography takes you by the hand with a series of underlining, shading, and contrived characters that highlight important sections of the code. Whereas in most books the 'Typographical Conventions Used' section is fluff, read and memorize this section before you cross the river regex with Friedl. You can't journey to the other side without it.

"So, what exactly is a regular expression? What makes it regular? Don't look for those answers here. Friedl gives you practical concepts, not a theoretical framework. He defines regular expressions as 'the key to powerful, flexible, and efficient text processing.' He clarifies that with 'regular expressions... allow you to describe and parse text.' That is the closest thing to a definition of regular expressions in the book. That is also like defining the sun as our source of heat and light, but failing to mention that it is the ball of flame in the center of the solar system. The title of the book is not The Theory of Regular Expressions but Mastering Regular Expressions. Look for practical advice on crafting efficient regexes at your desk and not for conversation tidbits in the break room."

-- Don Bryson ( Copyright 1997 Dr. Dobbs Electronic Review of Computer Books (

"There's no better resource than Jeffrey Friedl's Mastering Regular Expressions (O'Reilly 1997) –a great source of sample expressions and detailed explanations of how regular expressions work their magic." --Jason Snell, MacWorld, Nov 1998