Michael J. Ross gave the second edition of Regular Expression Pocket Reference a score of 9/10 in his Slashdot review. He was particularly impressed by the lack of errors.
As of this writing, there are no unconfirmed errata (those submitted by readers but not yet checked by the author to see whether they are valid), and no confirmed ones, either. In fact, in my review of the first edition, published in 2004, it was noted that there were no unconfirmed errata, despite the book being out for some time prior to that review. The most likely explanation is that the author — in addition to any technical reviewers — did a thorough job of checking all of the regular expressions in the book, along with the sample code that make use of them. These efforts have paid off with the apparent absence of any errors in this new edition — something unseen in any other technical book with which I am familiar.
I’m sure that the book isn’t actually error free, but the fact that it can masquerade as so is a tribute to the tech reviewers, Jeffrey Friedl, Philip Hazel, Steve Friedl, Ola Bini, Ian Darwin, Zak Greant, Ron Hitchens, A.M. Kuchling, Tim Allwine, Schuyler Erle, David Lents, Evan Henshaw-Plath, Rich Bowen, Eric Eisenhart, and Brad Merrill, and to my editors Andy Oram, Nat Torkington, and Linda Mui. That’s a lot of people for such a small book but the draft I turned in warranted them. Thank you.
My goals for the second edition were to increase coverage for things that I used (it turns out that one of the best reasons to write a book is so you can look things up later) and to add content for system administrators (who, based on feedback, seemed like the biggest users of the book). I’m a ruby developer now, so this edition has a ruby chapter, plus I added an Apache chapter and a cookbook of common regular expressions for the system administrators.
People often ask me why I covered so many implementations and the answer is because as a web developer I used regular expressions in so many places: ruby/perl, javascript, shell, vim, and apache. I bet system administrators are the same way.
Make sure to buy a few copies from Amazon.