The following font conventions are used in this book:

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We have a web site for the book, where we’ll list examples, errata, and any plans for future editions. It also offers a downloadable set of text files (and a couple of Perl programs) which are useful, but not required, when doing some of the exercises. You can access this page at:

For more information about this book and others, see the O’Reilly web site:

You are invited to copy the code in the book and adapt it for your own needs. Rather than copying by hand, however, we encourage you to download the code from http://www.oreilly.com/catalog/lperl3/.

For the curious, here’s how Randal tells the story of how this book came about:

After I had finished the first Programming Perl book with Larry Wall (in 1991), I was approached by Taos Mountain Software in Silicon Valley to produce a training course. This included having me deliver the first dozen or so courses and train their staff to continue offering the course. I wrote the course for them^[1] and delivered it for them as promised.

On the third or fourth delivery of that course (in late 1991), someone came up to me and said, “you know, I really like Programming Perl, but the way the material is presented in this course is so much easier to follow—you oughta write a book like this course.” It sounded like an opportunity to me, so I started thinking about it.

I wrote to Tim O’Reilly with a proposal based on an outline that was similar to the course I was presenting for Taos—although I had rearranged and modified a few of the chapters based on observations in the classroom. I think that was my fastest proposal acceptance in history—I got a message from Tim within fifteen minutes saying “we’ve been waiting for you to pitch a second book—Programming Perl is selling like gangbusters.” That started the effort over the next eighteen months to finish the first edition of Learning Perl.

During that time, I was starting to see an opportunity to teach Perl classes outside Silicon Valley^[2], so I created a class based on the text I was writing for Learning Perl. I gave a dozen classes for various clients (including my primary contractor, Intel Oregon), and used the feedback to fine-tune the book draft even further.

The first edition hit the streets on the first day of November, 1993^[3] and became a smashing success, frequently even outpacing Programming Perl book sales.

The back-cover jacket of the first book said “written by a leading Perl trainer.” Well, that became a self-fulfilling prophesy. Within a few months, I was starting to get email from all over the United States from people asking to have me teach at their site. In the following seven years, my company became the leading worldwide on-site Perl training company, and I had personally racked up (literally) a million frequent-flier miles. It didn’t hurt that the Web started taking off about then, and the webmasters and webmistresses picked Perl as the language of choice for content management, interaction through CGI, and maintenance.

For the past two years, I’ve been working closely with Tom Phoenix in his role as lead trainer and content manager for Stonehenge, giving him charter to experiment with the “Llama” course by moving things around and breaking things up. When we had come up with what we thought was the best major revision of the course, I contacted O’Reilly and said “it’s time for a new book!” And now you’re reading it.

Some of the differences you may notice from prior editions:

From Randal. I want to thank the Stonehenge trainers past and present (Joseph Hall, Tom Phoenix, Chip Salzenberg, brian d foy, and Tad McClellan) for their willingness to go out and teach in front of classrooms week after week and to come back with their notes about what’s working (and what’s not) so we could fine-tune the material for this book. I especially want to single out my co-author and business associate, Tom Phoenix, for having spent many, many hours working to improve Stonehenge’s Llama course and to provide the wonderful core text for most of this book.

I also want to thank everyone at O’Reilly, especially our very encouraging and patient editor, Linda Mui, and Tim O’Reilly himself for taking a chance on me in the first place with the Camel and Llama books.

I am also absolutely indebted to the thousands of people who have purchased the past editions of the Llama so that I could use the money to stay “off the streets and out of jail,” and to those students in my classrooms who have trained me to be a better trainer, and to the stunning array of Fortune 1000 clients who have purchased our classes in the past and will continue to do so into the future.

As always, a special thanks to Lyle and Jack, for teaching me nearly everything I know about writing. I won’t ever forget you guys.

From Tom. I’ve got to echo Randal’s thanks to our editor, Linda Mui, for her patience in pointing out which jokes and footnotes were most excessive, while pointing out that she is in no way to blame for the ones that remain. Both she and Randal have guided me through the process of writing, and I am grateful.

And another echo with regard to Randal and the other Stonehenge trainers, who hardly ever complained when I unexpectedly updated the course materials to try out a new teaching technique. You folks have contributed many different viewpoints on teaching methods that I would never have seen.

For many years, I worked at the Oregon Museum of Science and Industry (OMSI), and I’d like to thank the folks there for letting me hone my teaching skills as I learned to build a joke or two into every activity, explosion, or dissection.

To the many folks on Usenet who have given me your appreciation and encouragement for my contributions there, thanks. As always, I hope this helps.

Of course, deep thanks are due especially to my co-author, Randal, for giving me the freedom to try various ways of presenting the material both in the classroom and here in the book, as well as for the push to make this material into a book in the first place. And without fail, I must say that I am indeed inspired by your on-going work to ensure that no one else becomes ensnared by the legal troubles that have stolen so much of your time and energy; you’re a fine example.

From Both of Us. Thanks to our reviewers (Elaine Ashton, Kevin Bingham, Jarkko Hietaniemi, Joe Johnston, and Ben Tilly) for providing comments on the draft of this book.

Thanks also to our many students who have let us know what parts of the course material have needed improvement over the years. It’s because of you that we’re both so proud of it today.

Thanks to the many Perl Mongers who have made us feel at home as we’ve visited your cities. Let’s do it again sometime.

And finally, our sincerest thanks to our friend Larry Wall, for having the wisdom to share his really cool and powerful toys with the rest of the world so that we can all get our work done just a little bit faster, easier, and with more fun.