Perl

The sixth edition of this bestselling Perl tutorial includes recent changes to the language. Years of classroom testing and experience helped shape the book's pace and scope, and this edition is packed with exercises that let readers practice the concepts while they follow the text.

The book has an introductory chapter that gets the reader started quickly with programming in Perl. The initial part of the book discusses Perl expressions, statements, control flow, built-in data types such as arrays and hashes, and complex data structures built using references. On Perl has several chapters covering specialized topics. The chapter on socket-based network programming deals with forking and using fork to write complex interactive client-server programs. There is a chapter with in-depth discussion of CGI programming including error-handling and security issues that arise. The chapter on web-client programming deals with writing programs that access Web pages, fill up GET and POST forms, handle cookies and redirected Web pages. The book has several unique chapters not found in any other book on Perl in the market. The chapter on security discusses hashes such as MD5, message authentication codes (MACs), digital signature schemes, and encryption techniques such as DES, Rijndael, and RSA. Other chapters deal with writing recursive programs that work with files and directories; this chapter also discusses predefined modules that deal with portability in file names and paths across operating systems, recursive traversal of file hierarchies and tarring and untarring of filles. The chapter on functional programming illustrates that Perl functions are first-class, can be used to write closures and can be composed to form more complex functions. In particular, this can be useful for programming in artificial intelligence.

This book aims to give existing Perl programmers more detailed knowledge of some of the more advanced elements of the language.

A Perl expert can solve a problem in a few lines of well-tested code. Now you can unlock these powers for yourself. Modern Perl teaches you how Perl really works. It's the only book that explains Perl thoroughly, from its philosophical roots to the pragmatic decisions that help you solve real problems--and keep them solved. You'll understand how the language fits together and discover the secrets used by the global Perl community. This beloved guide is now completely updated for Perl 5.22. When you have to solve a problem now, reach for Perl. When you have to solve a problem right, reach for Modern Perl. Discover how to scale your skills from one-liners to asynchronous Unicode-aware web services and everything in between. Modern Perl will take you from novice to proficient Perl hacker. You'll see which features of modern Perl will make you more productive, and which features of this well-loved language are best left in the past. Along the way, you'll take advantage of Perl to write well-tested, clear, maintainable code that evolves with you. Learn how the language works, how to take advantage of the CPAN's immense trove of time-tested solutions, and how to write clear, concise, powerful code that runs everywhere. Specific coverage explains how to use Moose, how to write testable code, and how to deploy and maintain real-world Perl applications. This new edition covers the new features of Perl 5.20 and Perl 5.22, including all the new operators, standard library changes, bug and security fixes, and productivity enhancements. It gives you what you need to use the most up-to-date Perl most effectively, all day, every day. What You Need: Perl 5.16 or newer (Perl 5.20 or 5.22 preferred). Installation/upgrade instructions included.

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.

Written for biomedical professionals and hospital practitioners interested in creating their own programs, Perl Programming for Medicine and Biology, discusses and reviews biomedical data resources, data standards, data organization, medicolegal and ethical conduct for data miners, and grants-related data sharing responsibilities. It teaches readers the basic Perl programming skills necessary for collecting, analyzing, and distributing biomedical data and provides solutions to in-depth problems that face researchers and healthcare professionals. Non-technical "Background" sections open each chapter to help non-programmers easily comprehend programming procedures. Explanations are provided for the biomedical issues underlying the Perl scripts that follow, and examples of real-world implementation are provided. Perl Programming for Medicine and Biology will show you how to transform, merge, and examine large and complex databases with ease.

This introduction to computational molecular biology will help programmers and biologists learn the skills needed to start work in this important, expanding field. The author explains many of the basic computational problems and gives concise, working programs to solve them in the Perl programming language. With minimal prerequisites, the author explains the biological background for each problem, develops a model for the solution, then introduces the Perl concepts needed to implement the solution. The book covers pairwise and multiple sequence alignment, fast database searches for homologous sequences, protein motif identification, genome rearrangement, physical mapping, phylogeny reconstruction, satellite identification, sequence assembly, gene finding, and RNA secondary structure. The concrete examples and step-by-step approach make it easy to grasp the computational and statistical methods, including dynamic programming, branch-and-bound optimization, greedy methods, maximum likelihood methods, substitution matrices, BLAST searching, and Karlin-Altschul statistics. Perl code is provided on the accompanying CD.

Part of the fun of programming in Perl lies in tackling tedious tasks with short, efficient, and reusable code. Often, the perfect tool is the one-liner, a small but powerful program that fits in one line of code and does one thing really well. In Perl One-Liners, author and impatient hacker Peteris Krumins takes you through more than 100 compelling one-liners that do all sorts of handy things, such as manipulate line spacing, tally column values in a table, and get a list of users on a system. This cookbook of useful, customizable, and fun scripts will even help hone your Perl coding skills, as Krumins dissects the code to give you a deeper understanding of the language. You'll find one-liners that: * Encode, decode, and convert strings * Generate random passwords * Calculate sums, factorials, and the mathematical constants π and e * Add or remove spaces * Number lines in a file * Print lines that match a specific pattern * Check to see if a number is prime with a regular expression * Convert IP address to decimal form * Replace one string with another And many more! Save time and sharpen your coding skills as you learn to conquer those pesky tasks in a few precisely placed keystrokes with Perl One-Liners.