Great reference to an arcane subject
I'm scared of regular expressions. They vex me constantly at work whether trying to figure out someone else's Apache RewriteRules or Perl or just trying myself to do mildly clever things in vi and sed. They are a headache.
A coworker let me browse his copy of this wonderful little book and I was hooked. I actually tried to buy one that day on the way home, but they were out of stock and so I permitted Amazon to ship me one.
In addition to brief explanations of the different types of regexes in the wild (based on the comprehensive Mastering title, also from ORA), there are detailed quick references to all of the different implementations including several common languages (Perl, PHP, C#, and several others) and software packages (including sed, Apache, vi and many others). All of their various quicks and "features" are explained briefly and there are some examples.
No one hacking around in Unix or doing much programming should be without this book, unless they are already a regex wizard, and I think even they'd find it handy.
Just a mus have
Most developers know how to write regular expressions, almost none of them can read them. And if you are saying that you can. Well congratulations to you. You are one of the 0.1% of developers that can or you are one of those who think they can.
The books physical appearance is so compact that it has become a permanent item on my working desk. And is often used.
A good multilanguage reference
You know those times when you know what you want to do, but are not sure of the correct form, this is the book to grab. It has been my book to grab as a reference rather than trying to find the right language book. This is not the book to learn the language from, however. You will find your copy will be well worn if you do lots of coding.
Regular expressions, part of a healthy breakfast
Pocket references are not meant to teach you anything from the beginning, but to be everyday references in known and new environments. In other words, if you don't know regular expressions, then go to "Mastering Regular Expressions". If you're still here, then you'll get a cheat sheet on steroids for languages ranging from bug-prone JavaScript to the King and Queen of robustness, Perl and Python. Although everything claims to be PCRE these days, particular examples in every language available is a plus for anyone. A must for any type of user input validation.
Good book for well-versed developers in/using multiple programming languages
From the back cover of the Regular Expression Pocket Reference: "Ideal as a quick reference..." and "... makes an ideal on-the-job companion." All this is true if you are well-versed in regular expressions and use multiple programming languages (and confuse the syntax).
I like the use of the same examples across programming languages (where applicable).
The recipes in the cookbook section are great, although I would have liked to see additional recipes (like stripping HTML tags, matching credit card numbers etc...). Of course the examples are endless and over time one builds his/her own recipe collection. At least this is a good place to start.
