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The World's Easiest Perl 5 Tutorial-Updated for Today's Applications and "Modern Perlö Best Practices

"When I look at my bookshelf, I see eleven books on Perl programming. Perl by Example, Third Edition, isn't on the shelf; it sits on my desk, where I use it almost daily. I still think it is the best Perl book on the market for anyone-beginner or seasoned programmer-who uses Perl daily.ö

-Bill Maples, Enterprise Network Support, Fidelity National Information Services

Perl by Example, Fifth Edition, is the proven, easy way to master Perl 5 programming. Legendary Silicon Valley programming instructor Ellie Quigley has fully updated and focused her classic text on today's key Perl applications, especially automation, testing, data extraction, and legacy code maintenance. She has also revised this edition to reflect "modern Perlö practices that have emerged since Perl 5.10.

Quigley illuminates every technique with focused, classroom-tested code examples. For each example, she shows you code, input, and output, and provides detailed, line-by-line explanations of how the code generates that output. And her coverage is comprehensive, from basic syntax to regular expression handling, files, references, objects, working with databases, and much more.plus appendices that contain a complete list of functions and definitions, command-line switches, special variables, and popular modules.

New in This Edition

 Modern Perl approaches to using data types, operators, conditions, subroutines, packages, modules, references, pointers, files, objects, and more

 Many new examples, covering automation, testing, and data extraction

 A tutorial on writing object-oriented Perl with the Moose object system

 An introduction to Dancer, a powerful web application framework designed to replace CGI

 Updated code examples throughout

More than 50,000 sysadmins, power users, and developers have used this book's previous editions to become expert Perl programmers, and you can, too-even if you're completely new to Perl. Then, once you're an expert, you'll routinely return to this practical guide as the best source for reliable answers, solutions, and code. A more focused, quicker read than ever, this clear and practical guide will take you from your first Perl script to advanced applications. It's the only Perl text you'll need.

Ellie Quigley has taught scripting in Silicon Valley for more than twenty-five years. Her Perl and shell programming classes at the University of California, Santa Cruz Extension are part of Silicon Valley lore. Her other best-selling Prentice Hall books include UNIX® Shells by Example, Fourth Edition; PHP and MySQL by Example (with Marko Gargenta); and JavaScript by Example. A major player in developing UCSC's Silicon Valley Extension program, she has created and customized courses for pioneering firms, including Xilinx, NetApp, Yahoo, and Juniper.




Preface xxv


Chapter 1: The Practical Extraction and Report Language 1

1.1 What Is Perl? 1

1.2 What Is an Interpreted Language? 2

1.3 Who Uses Perl? 3

1.4 Where to Get Perl 6

1.5 Perl Documentation 9

1.6 What You Should Know 13

1.7 What's Next? 13


Chapter 2: Perl Quick Start 15

2.1 Quick Start, Quick Reference 15

2.2 Chapter Summary 32

2.3 What's Next? 32


Chapter 3: Perl Scripts 33

3.1 Getting Started 33

3.2 Filehandles 37

3.3 Variables (Where to Put Data) 37

3.4 Summing It Up 42

3.5 Perl Switches 44

3.6 What You Should Know 47

3.7 What's Next? 47

Exercise 3 Getting with It Syntactically 48


Chapter 4: Getting a Handle on Printing 49

4.1 The Special Filehandles STDOUT, STDIN, STDERR 49

4.2 Words 51

4.3 The print Function 51

4.4 Fancy Formatting with the printf Function 69

4.5 What Are Pragmas? 74

4.6 What You Should Know 78

4.7 What's Next? 79

Exercise 4 A String of Perls 79


Chapter 5: What's In a Name? 81

5.1 More About Data Types 81

5.2 Scalars, Arrays, and Hashes 87

5.3 Array Functions 105

5.4 Hash (Associative Array) Functions 125

5.5 What You Should Know 140

5.6 What's Next? 141

Exercise 5 The Funny Characters 141


Chapter 6: Where's the Operator? 145

6.1 About Perl Operators-More Context 145

6.2 Mixing Types 148

6.3 Precedence and Associativity 149

6.4 What You Should Know 178

6.5 What's Next? 179

Exercise 6 Operator, Operator 179


Chapter 7: If Only, Unconditionally, Forever 181

7.1 Control Structures, Blocks, and Compound Statements 182

7.2 Statement Modifiers and Simple Statements 188

7.3 Repetition with Loops 190

7.4 Looping Modifiers 202

7.5 What You Should Know 217

7.6 What's Next? 217

Exercise 7 What Are Your Conditions? 218


Chapter 8: Regular Expressions-Pattern Matching 219

8.1 What Is a Regular Expression? 219

8.2 Modifiers and Simple Statements with Regular Expressions 221

8.3 Regular Expression Operators 225

8.4 What You Should Know 243

8.5 What's Next? 243

Exercise 8 A Match Made in Heaven 244


Chapter 9: Getting Control-Regular Expression Metacharacters 245

9.1 The RegExLib.com Library 245

9.2 Regular Expression Metacharacters 247

9.3 Unicode 290

9.4 What You Should Know 294

9.5 What's Next? 295

Exercise 9 And the Search Goes On . . . 295


Chapter 10: Getting a Handle on Files 297

10.1 The User-Defined Filehandle 297

10.2 Reading from STDIN 307

10.3 Passing Arguments 333

10.4 File Testing 342

10.5 What You Should Know 344

10.6 What's Next? 344

Exercise 10 Getting a Handle on Things 345


Chapter 11: How Do Subroutines Function? 347

11.1 Subroutines/Functions 348

11.2 Passing Arguments and the @_ Array 352

11.3 What You Should Know 373

11.4 What's Next? 373

Exercise 11 I Can't Seem to Function Without Subroutines 374


Chapter 12: Does This Job Require a Reference? 377

12.1 What Is a Reference? 377

12.2 What You Should Know 404

12.3 What's Next? 404

Exercise 12 It's Not Polite to Point! 405


Chapter 13: Modularize It, Package It, and Send It to the Library! 407

13.1 Before Getting Started 407

13.2 The Standard Perl Library 417

13.3 Modules from CPAN 436

13.4 Using Perlbrew and CPAN Minus 441

13.5 What You Should Know 444

13.6 What's Next? 445

Exercise 13 I Hid All My Perls in a Package 445


Chapter 14: Bless Those Things! (Object-Oriented Perl) 447

14.1 The OOP Paradigm 447

14.2 Perl Classes, Objects, and Methods-Relating to the Real World 450

14.3 Anonymous Subroutines, Closures, and Privacy 478

14.4 Inheritance 484

14.5 Plain Old Documentation-Documenting a Module 501

14.6 Using Objects from the Perl Library 508

14.7 What You Should Know 512

14.8 What's Next? 513

Exercise 14 What's the Object of This Lesson? 513


Chapter 15: Perl Connects with MySQL 519

15.1 Introduction 519

15.2 What Is a Relational Database? 520

15.3 Getting S