Rating: 
Summary: I wish I could give it 6 stars!
Review: The book is a perfection! Everything is excellent here: style, accuracy, language. Jeffrey managed to give formal and complete coverage of formal parts of regular expressions together with detailed explanations of WHEN and HOW certain expressions should be used in real world.
Use of regular expressions can turn into a mess because usually there are many ways of mapping given task to regular expressions. When going through every practical task, Jeffrey Friedl carefully explains what variant should be used and why. To let readers check their understanding, author often puzzles them with brief tasks that readers are supposed to solve and verify the answer on a next page. I enjoyed every puzzle, and it really helped me to master my skills. While still reading the book, I was able within a few hours to write a simple RE-based parser for my work.
Highly recommended!
Rating:
Summary: Simply Outstanding
Review: I bought this book on a whim, mainly because I try to buy (and read... ugh!) a hard-core technical book every month or so, but mainly because my UNIX scripting abilities have become rusty with disuse. I used to be able to write a tight, 10-line csh script to mangledit thousands of files at a single time. Now I hack away at files manually with vi. The other day, I even forgot how to search & replace. My kung fu isn't nearly what it used to be.It usually takes me about a month to slog through a new book (especially academic texts, which are great but make you want to have a stiff martini before each new chapter) but I tore through Friedl's book in a few days. It's an outstanding reference for understanding & learning to use regular expressions. Regexes can be cryptic to say the least, but Friedl offers many examples, broken down into step-by-step instructions and explanations of how each regex works (in many cases, right down to the individual character level). He covers a variety of platforms and languages - the hardcore Perl enthusiast will enjoy this book greatly, but he offers fairly equal time to alternative languages like Java and the "grep" family. All that said, this book is an outstanding technical reference, pure and simple, for two reasons: - Friedl uses an interesting new typesetting convention to illustrate which sections of text are regular expressions, and which sections are not. It's hard to describe (and impossible to reproduce here) but they look like 90-degree braces at the upper-left and lower-right corners. This is a FANTASTIC approach and I for one would love to see this extended to other technical books. - Speaking of other things I would love to see extended to other technical books, THIS BOOK HAS ALMOST NO ERRORS! This is even more impressive considering the fact that, with regular expressions, screwing up EVEN A SINGLE CHARACTER is significant. Nothing [upsets]memore than spending $50-100 perfectly good dollars on a sloppy, error-laden, grammatically-challenged, poorly-edited, ill-reviewed and badly-structured book (which pretty much describes 90% of all the technical books out there). He made a few mistakes, the vast majority of which are extremely trivial in nature, and all of which were quickly posted to his website as errata. If only the other 90% of the technical authors out there were even half as diligent. All told, this book belongs on your bookshelf.
Rating:
Summary: If anything like the 1st Edition...
Review: Regular Expressions is not intuitive, but they sure solve a lot of ugly text-related problems. Mastering Regular Expressions will teach you the required how to's & pitfall's. Previous reviewers are right, there's a lot here, but since when is throughness a crime?
Rating:
Summary: Separates the players from the punters
Review: Regular expressions help you "lex", or make sense of text input to your program in a method much more powerful than your junior college or MCSE program taught you.
In the mid '80's I wrote a lexer/parser/compiler as a class assignment. I definitely used regular expressions in order to break the input down into lexemes so I could generate object code. Back then, we learned regular expressions "the hard way".
This book makes learning them easier. You don't have to be writing a compiler in order to make use of regexes! Spam filtering is my current use for them. 2nd ed. vs. 1st ed.: He attacks the subject more seriously.
He (as far as I can tell) dropped "vi" coverage.
He uses Perl 5.8 for his examples, though has chapters for the most popular regex engines, including VB.NET.
Summary: I think it's easier to follow and more business-oriented than the 1st edition, though don't toss the 1st edition. You'll need them both.
Rating: 
Summary: Poorly assembled time waster
Review: I found little use for this book and I think any moderate to average perl programmer would have no need for it.
The book itself is much too long and full of uninteresting fluff that only a few really lonely will bother to read. Luckily I didn't have to waste any money on this book, and I urge you not to waste yours.
A book on this subject could have been interesting and helpful, but Jeff Fried ensures that you will get no joy nor use from reading it.
Rating: 
Summary: Very thorough. Very Unix.
Review: This book is a good follow-up on the 80 pages about Pattern Matching in Programming Perl (3rd Ed.) if you need to get into more detail. The book is really most useful to Perl programmers. It covers RegEx's in great depth and shares experiences which would take years to build up on your own. The book claims to cover platform-neutral tools, but the content of the book seems to be written almost solely from Unix experiences. If you want to learn more about RegEx implementation on a non-Unix platform, chances are this book won't fulfill your needs. However, there are exceptions. The Microsoft .NET Framework e.g. is an implementation designed for compatibility with Perl 5 RegEx's (adding features such as right-to-left matching). Buy this book if you're a Unix user and want to know all about Regular Expressions. Otherwise, think twice. It might be a bit too specific for your needs.
Rating:
Summary: i wish all tech books were this good
Review: I can't say enough good things about this book. Regular expressions are such a powerful concept, but some of that power would be easy to miss if not guided correctly through the topic. Jeffrey Freidl does a great job of making a potentially very dry subject interesting, even while getting very involved in all the complexities that are inherent in such a powerful abstraction. He also does a good job of presenting both the general topic of regular expressions and the specific characteristics of the various tools available to process them. This is a book that you will come back to many times. I actually read it as a precursor to learning Perl several years ago. Then just recently I revisited it while taking a class on compiler construction and found that it still had useful insights for me. If you're a committed programmer, this book should be on your shelf. Also, the criticisms I've read in reviews here are pretty misguided. It is "chatty", because the author has a genuine enthusiasm for his subject. It is also not a "teach yourself regular expressions in 24 hours" kind of book. There are actually lots of cookbook style examples, but the main point of the book is to give you a solid enough understanding of the general topic that you don't need examples to craft your regexes. In this case, little patience as a reader will be much rewarded.
Rating:
Summary: I need more stars... Bravo Jeffrey
Review: Jeffrey Friedl's "Matering Regular Expressions" does a facinating job in taking you through the jungle (and I mean jungle) of RegExp. I am a Perl/CGI programmer, and I had considered myself good at RegExp even before I read this book. Most of the things I knew were from Programming Perl, 3rd edition (chapter 5, Pattern Matching). But I still decided to give Jeffrey a chance since I was having some trouble with my Parse::Syntax module, which is designed to parsing *any* programming language and highlighting the syntax accordingly (provided it has a syntax/grammer file written for the specific language). The accuracy of the parser (and more importantly the speed) does depend on well crafted regular expressions. As I started reading the book, I couldn't stop. I took it to my school's cafeteria with me and no one could make me leave untill I finished the whole book. I was excited. I was pleased! Here is the outline of tha chapters: Chapter 1 and 2 introduce you to regular expressions and give some basic regex examples. Mail utility and date matching is two of them. Chapter 3 mostly talks about conventions that all the regex tools follow and their differences. Chapter 4 deals with Traditional NFA, POSIX NFA and DFA regex engines and their pros and cons. What you'll like the most is the details provided by the author on each and every single example. He also uses a lot of step-by-step illustrations to take you deeper into the regex engine itself and see/feel how it works. He shows the point of backtrackings and provides awesome benchmarks. He uses such examples of matching a quote, allowing escaped quotes inside the pattern, matching C-style comments, IP addresses and many more. Chapter 5 deals with writing efficient regular expressions for NFA engines. It also re-vists some of the examples provided in the previous chapter and fine-tunes them. Chapter 6 and 7 deals with Tool-Language specific features of Regex engines. Chapter 6 is dedicated to Awk, Tcl and GNU Emacs, whereas chapter 7 is entirely dedicated to Perl, good over 100 pages of Perlism. It's true that there're features that Perl 5.6 offers when it comes to regex that didn't exist at the time this book went to press, (lookbehinds, for example). But this no way makes this book dated. Just take my word for it. Jeffrey put together a great masterpiece that will not die for many years, no matter how fast the technology tends to enhance
Haven't read anything more exciting than this for many years.
Rating:
Summary: Eureka!
Review: Okay, so maybe I'm no Archimedes, but this book suddenly illuminated the world of regular expressions for me. I'd toiled through three or four other books, some of them pretty good, without getting it.
After just a few chapters of this one, I can finally say that I understand regular expressions and can use them to my advantage instead of just being vaguely aware that there is a better way to do what I've been trying to do.
Don't wait, buy it now!
Rating:
Summary: regular expressions are very useful
Review: I have been getting into regular expressions, as I realized, how powerful and useful they are, I started to use more advanced features, and started to run into topics that weren't fully documented in the python or .NET documentation. I guess, I never looked at Perl documentation. Though this book turned out to be a real gem. Each time so far that I needed some help with regex, the book showed it to me quickly and easy to understand. Plus, O'Reilly books really rock. I'm going through a lot of technical books. And, by now O'Reilly convinced me that they have a good quality control.
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