This is the third in O’Reilly’s series of landmark Perl tutorials, which started with Learning Perl, the bestselling introduction that taught you the basics of Perl syntax, and Intermediate Perl, which taught you how to create re-usable Perl software. Mastering Perl pulls everything together to show you how to bend Perl to your will. It convey’s Perl’s special models and programming idioms.

This book isn’t a collection of clever tricks, but a way of thinking about Perl programming so you can integrate the real-life problems of debugging, maintenance, configuration, and other tasks you encounter as a working programmer.

The book explains how to:

• Use advanced regular expressions, including global matches, lookarounds, readable regexes, and regex debugging
• Avoid common programing problems with secure programming techniques
• Profile and benchmark Perl to find out where to focus your improvements
• Wrangle Perl code to make it more presentable and readable
• See how Perl keeps track of package variables and how you can use that for some powerful tricks
• Define subroutines on the fly and turn the tables on normal procedural programming.
• Modify and jury rig modules to fix code without editing the original source
• Let your users configure your programs without touching the code
• Learn how you can detect errors Perl doesn’t report, and how to tell users about them
• Let your Perl program talk back to you by using Log4perl
• Store data for later use in another program, a later run of the same program, or to send them over a network
• Write programs as modules to get the benefit of Perl’s distribution and testing tools

Appendices include “brian’s Guide to Solving Any Perl Problem” to improve your troubleshooting skills, as well as suggested reading to continue your Perl education. Mastering Perl starts you on your path to becoming the person with the answers, and, failing that, the person who knows how to find the answers or discover the problem.

This book is intended for anyone who has an interest in useful Perl scripting, in particular on the Windows platform, for the purpose of incident response, and forensic analysis, and application monitoring. While a thorough grounding in scripting languages (or in Perl specifically) is not required, it is helpful in fully and more completely understanding the material and code presented in this book. This book contains information that is useful to consultants who perform incident response and computer forensics, specifically as those activities pertain to MS Windows systems (Windows 2000, XP, 2003, and some Vista). My hope is that not only will consultants (such as myself) find this material valuable, but so will system administrators, law enforcement officers, and students in undergraduate and graduate programs focusing on computer forensics.

*Perl is the third most commonly used programming language in the world
*Helps security professionals in updating settings on a remote server several cities away, collecting data for a report to management, and more
*The companion Web site for the book contains dozens of scripts the reader can download and use today

Written for web developers with basic Perl skills, this book guides new users through the open-source Perl-based Model-View-Controller Catalyst framework using real-world examples and systematic code snippets, covering application design, development, testing, and deployment. If you are excited by Ruby on Rails but prefer the familiarity of Perl, get this book and get started. The way that many web applications are implemented makes development painful and repetitive. Catalyst solves this problem, organizing your web application to design and implement it in a natural, maintainable, and testable way. Its philosophies are Do It Yourself and Don’t Repeat Yourself. Everything is written only once; database access and configuration are centralized; you just write actions for each URL in your application and Catalyst handles the details. Catalyst is designed to be reliable; the code is well tested; there are hundreds of production applications, thousands of users, and a thriving community.

Perl/Tk is the marriage of the Tk graphical toolkit with Perl, the powerful programming language used primarily for system administration, web programming, and database manipulation. With Perl/Tk, you can build Perl programs with an attractive, intuitive GUI interface with all the power of Perl behind it. Mastering Perl/Tk is the “bible” of Perl/Tk: It’s not only a great book for getting started, but the best reference for learning the techniques of experienced Perl/Tk programmers. The first half of the book contains the basics on how to use Perl/Tk, and then branches out into advanced applications with a series of extensive program examples. The result is a book accessible for novices, and invaluable for experienced programmers ready to learn the next step in the elegant and effective use of Perl/Tk. The book includes:

• A dissection of the MainLoop, including how to use callbacks and bindings effectively
• Coverage of the Tix widgets, an extended set of widgets that are a part of the standard Perl/Tk distribution
• Working with images in Perl/Tk, including bitmaps, pixmaps, photos, and how to compose a compound image type
• How to create custom mega-widgets in Perl/Tk, both composite and derived
• Handling interprocess communication with Perl/Tk, both with standard Unix utilities (pipes and sockets) and with the send command designed for direct communication between Tk applications
• Developing your own Tk widget in the C language
• Examples of web applications written with Perl/Tk and the LWP library

The book also includes appendices on installing Perl/Tk, a complete quick-reference for each standard widget, and listings of all the extended examples in the book. Nancy Walsh is the author of Learning Perl/Tk, and Steve Lidie wrote the Perl/Tk Pocket Reference as well as a series of Perl/Tk articles in The Perl Journal. Together, they have written Mastering Perl/Tk to be the definitive guide to Perl/Tk.

The primary interface for database programming in Perl is DBI. Programming the Perl DBI is coauthored by Alligator Descartes, one of the most active members of the DBI community, and by Tim Bunce, the inventor of DBI. The book explains the architecture of DBI, shows you how to write DBI-based programs, and reveals both DBI’s nuances and the peculiarities of each individual DBD. This is the definitive book for database programming in Perl.
One of the greatest strengths of the Perl programming language is its ability to manipulate large amounts of data. Database programming is therefore a natural fit for Perl, not only for business applications but also for CGI-based web and intranet applications. The primary interface for database programming in Perl is DBI. DBI is a database-independent package that provides a consistent set of routines regardless of what database product you use–Oracle, Sybase, Ingres, Informix, you name it. The design of DBI is to separate the actual database drivers (DBDs) from the programmer’s API, so any DBI program can work with any database, or even with multiple databases by different vendors simultaneously. Programming the Perl DBI is coauthored by Alligator Descartes, one of the most active members of the DBI community, and by Tim Bunce, the inventor of DBI. For the uninitiated, the book explains the architecture of DBI and shows you how to write DBI-based programs. For the experienced DBI dabbler, this book reveals DBI’s nuances and the peculiarities of each individual DBD. The book includes:

* An introduction to DBI and its design
* How to construct queries and bind parameters
* Working with database, driver, and statement handles
* Debugging techniques
* Coverage of each existing DBD
* A complete reference to DBI

This is the definitive book for database programming in Perl.

mod_perl embeds the popular programming language Perl in the Apache web server, giving rise to a fast and powerful web programming environment. Written for Perl web developers and web administrators, Practical mod_perl is an extensive guide to the nuts and bolts of the powerful and popular combination of Apache and mod_perl. From writing and debugging scripts to keeping your server running without failures, the techniques in this book will help you squeeze every ounce of power out of your server. True to its title, this is the practical guide to mod_perl.
mod_perl embeds the popular programming language Perl in the Apache web server, giving rise to a fast and powerful web programming environment. Practical mod_perl is the definitive book on how to use, optimize, and troubleshoot mod_perl. New mod_perl users will learn how to quickly and easily get mod_perl compiled and installed. But the primary purpose of this book is to show you how to take full advantage of mod_perl: how to make a mod_perl-enabled Web site as fast, flexible, and easily-maintainable as possible. The authors draw from their own personal experience in the field, as well as the combined experience of the mod_perl community, to present a rich and complete picture of how to set up and maintain a successful mod_perl site. This book is also the first book to cover the “next generation” of mod_perl: mod_perl 2.0, a completely rewritten version of mod_perl designed for integration with Apache 2.0, which for the first time supports threads. The book covers the following topics, and more:

* Configuring mod_perl optimally for your web site
* Porting and optimizing programs for a mod_perl environment
* Performance tuning: getting the very fastest performance from your site
* Controlling and monitoring the server to circumvent crashes and clogs
* Integrating with databases efficiently and painlessly
* Debugging tips and tricks
* Maximizing security

Written for Perl web developers and web administrators, Practical mod_perl is an extensive guide to the nuts and bolts of the powerful and popular combination of Apache and mod_perl. From writing and debugging scripts to keeping your server running without failures, the techniques in this book will help you squeeze every ounce of power out of your server. True to its title, this is the practical guide to mod_perl.

The Perl Cookbook is a comprehensive collection of problems, solutions, and practical examples for anyone programming in Perl. You’ll find hundreds of rigorously reviewed Perl “recipes” for manipulating strings, numbers, dates, arrays, and hashes; pattern matching and text substitutions; references, data structures, objects, and classes; signals and exceptions; and much more.

The Perl Cookbook is a comprehensive collection of problems, solutions, and practical examples for anyone programming in Perl. Topics range from beginner questions to techniques that even the most experienced of Perl programmers will learn from. More than just a collection of tips and tricks, the Perl Cookbook is the long-awaited companion volume to Programming Perl, filled with previously unpublished Perl arcana. The Perl Cookbook contains thousands upon thousands of examples ranging from brief one-liners to complete applications. Covered topic areas spread across nearly four hundred separate “recipes,” including:

* Manipulation of strings, numbers, dates, arrays, and hashes
* Reading, writing, and updating text and binary files
* Pattern matching and text substitutions
* Subroutines, libraries, and modules
* References, data structures, objects, and classes
* Signals and exceptions
* Accessing text, hashes, and SQL databases
* Screen addressing, menus, and graphical applications
* Managing other processes
* Writing secure scripts
* Client-server programming
* Internet applications programming with mail, news, ftp, and telnet

These recipes were rigorously reviewed by scores of the best minds inside and outside Perl, foremost of which was Larry Wall, the creator of Perl himself. The Perl Cookbook is written by Tom Christiansen, Perl evangelist and coauthor of the bestselling Programming Perl and Learning Perl; and Nathan Torkington, Perl trainer and co-maintainer of the Perl Frequently Asked Questions list.

Many programmers would love to use Perl for projects that involve heavy lifting, but miss the many traditional algorithms that textbooks teach for other languages. Computer scientists have identified many techniques that a wide range of programs need, such as:

* Fuzzy pattern matching for text (identify misspellings!)
* Finding correlations in data
* Game-playing algorithms
* Predicting phenomena such as Web traffic
* Polynomial and spline fitting

Using algorithms explained in this book, you too can carry out traditional programming tasks in a high-powered, efficient, easy-to-maintain manner with Perl. This book assumes a basic understanding of Perl syntax and functions, but not necessarily any background in computer science. The authors explain in a readable fashion the reasons for using various classic programming techniques, the kind of applications that use them, and — most important — how to code these algorithms in Perl. If you are an amateur programmer, this book will fill you in on the essential algorithms you need to solve problems like an expert. If you have already learned algorithms in other languages, you will be surprised at how much different (and often easier) it is to implement them in Perl. And yes, the book even has the obligatory fractal display program. There have been dozens of books on programming algorithms, some of them excellent, but never before has there been one that uses Perl. The authors include the editor of The Perl Journal and master librarian of CPAN; all are contributors to CPAN and have archived much of the code in this book there. “This book was so exciting I lost sleep reading it.” Tom Christiansen

About the Author
Jarkko Hietaniemi is the creator and Master Librarian of CPAN: Comprehensive Perl Archive Network. He has also been known to frequent Perl developer forums. Luckily enough, getting his MSc in CS in the field of parallel computing didn’t interfere overly much with his Perl and UNIX hacking. During those savored moments of off-line time, he fancies gobbling up speculative fiction and popular science. His real life employer is Nokia Research Center.

John Macdonald has been using Perl commercially since 1988 for a suite of Unix system administration tools. His background with Unix dates back to the days when Unix was written in PDP-11 assembler and later includes representing the University of Waterloo at the first UNIX Users Meeting at City University of New York in the mid-1970s while finishing his M. Math degree. (In those days before the creation of Usenix, the people at the meeting would sit together around a single table.) In addition, his background includes work on compilers, kernel internals, device drivers and the like. He has also been observed partaking in recreational computing activities.

Jon Orwant, a well-known member of the Perl community, founded The Perl Journal and co-authored OReillys bestseller, Programming Perl, 3rd Edition.

Apache is the most popular web server on the Internet because it is free, reliable, and extensible. The availability of the source code and the modular design of Apache makes it possible to extend web server functionality through the Apache API. For the most part, however, the Apache API has only been available to C programmers, and requires rebuilding the Apache server from source. mod_perl, the popular Apache module used primarily for enhanced CGI performance, changed all that by making the Apache API available to Perl programmers. With mod_perl, it becomes simple to develop Apache modules with Perl and install them without having to rebuild the web server. Writing Apache Modules with Perl and C shows how to extend web server capabilities regardless of whether the programming language is Perl or C. The book explains the design of Apache, mod_perl, and the Apache API. It then demonstrates how to use them to perform for tasks like the following:

* Rewriting CGI scripts as Apache modules to vastly improve performance
* Server-side filtering of HTML documents, to embed special markup or code (much like SSI)
* Enhancing server log functionality
* Converting file formats on the fly
* Implementing dynamic navigation bars
* Incorporating database access into CGI scripts
* Customizing access control and authorization to block robots or to use an external database for passwords

The authors are Lincoln Stein and Doug MacEachern. Lincoln is the successful author of How to Set Up and Maintain a World Wide web Site and the developer of the widely used Perl CGI.pm module. Doug is a consultant and the creator of the innovative mod_perl Apache module. –This text refers to the Paperback edition.

Many programmers code by instinct, relying on convenient habits or a “style” they picked up early on. They aren’t conscious of all the choices they make, like how they format their source, the names they use for variables, or the kinds of loops they use. They’re focused entirely on problems they’re solving, solutions they’re creating, and algorithms they’re implementing. So they write code in the way that seems natural, that happens intuitively, and that feels good.

But if you’re serious about your profession, intuition isn’t enough. Perl Best Practices author Damian Conway explains that rules, conventions, standards, and practices not only help programmers communicate and coordinate with one another, they also provide a reliable framework for thinking about problems, and a common language for expressing solutions. This is especially critical in Perl, because the language is designed to offer many ways to accomplish the same task, and consequently it supports many incompatible dialects.

With a good dose of Aussie humor, Dr. Conway (familiar to many in the Perl community) offers 256 guidelines on the art of coding to help you write better Perl code–in fact, the best Perl code you possibly can. The guidelines cover code layout, naming conventions, choice of data and control structures, program decomposition, interface design and implementation, modularity, object orientation, error handling, testing, and debugging.

They’re designed to work together to produce code that is clear, robust, efficient, maintainable, and concise, but Dr. Conway doesn’t pretend that this is the one true universal and unequivocal set of best practices. Instead, Perl Best Practices offers coherent and widely applicable suggestions based on real-world experience of how code is actually written, rather than on someone’s ivory-tower theories on how software ought to be created.

Most of all, Perl Best Practices offers guidelines that actually work, and that many developers around the world are already using. Much like Perl itself, these guidelines are about helping you to get your job done, without getting in the way.

Praise for Perl Best Practices from Perl community members:

“As a manager of a large Perl project, I’d ensure that every member of my team has a copy of Perl Best Practices on their desk, and use it as the basis for an in-house style guide.” — Randal Schwartz

“There are no more excuses for writing bad Perl programs. All levels of Perl programmer will be more productive after reading this book.” — Peter Scott

“Perl Best Practices will be the next big important book in the evolution of Perl. The ideas and practices Damian lays down will help bring Perl out from under the embarrassing heading of “scripting languages”. Many of us have known Perl is a real programming language, worthy of all the tasks normally delegated to Java and C++. With Perl Best Practices, Damian shows specifically how and why, so everyone else can see, too.” — Andy Lester

“Damian’s done what many thought impossible: show how to build large, maintainable Perl applications, while still letting Perl be the powerful, expressive language that programmers have loved for years.” — Bill Odom

“Finally, a means to bring lasting order to the process and product of real Perl development teams.” — Andrew Sundstrom”Perl Best Practices provides a valuable education in how to write robust, maintainable Perl, and is a definitive citation source when coaching other programmers.” — Bennett Todd “I’ve been teaching Perl for years, and find the same question keeps being asked: Where can I find a reference for writing reusable, maintainable Perl code? Finally I have a decent answer.” — Paul Fenwick “At last a well researched, well thought-out, comprehensive guide to Perl style. Instead of each of us developing our own, we can learn good practices from one of Perl’s most prolific and experienced authors. I recommend this book to anyone who prefers getting on with the job rather than going back and fixing errors caused by syntax and poor style issues.” — Jacinta Richardson “If you care about programming in any language read this book. Even if you don’t intend to follow all of the practices, thinking through your style will improve it.” — Steven Lembark “The Perl community’s best author is back with another outstanding book. There has never been a comprehensive reference on high quality Perl coding and style until Perl Best Practices. This book fills a large gap in every Perl bookshelf.” — Uri Guttman