Perl Cookbook

Foreword; Preface; What's in This Book; What's New in This Edition; Platform Notes; Other Books; Conventions Used in This Book; We'd Like to Hear from You; Acknowledgments for the First Edition; Acknowledgments for the Second Edition; Chapter 1: Strings; 1.1 Introduction; 1.1 Accessing Substrings; 1.2 Establishing a Default Value; 1.3 Exchanging Values Without Using Temporary Variables; 1.4 Converting Between Characters and Values; 1.5 Using Named Unicode Characters; 1.6 Processing a String One Character at a Time; 1.7 Reversing a String by Word or Character; 1.8 Treating Unicode Combined Characters as Single Characters; 1.9 Canonicalizing Strings with Unicode Combined Characters; 1.10 Treating a Unicode String as Octets; 1.11 Expanding and Compressing Tabs; 1.12 Expanding Variables in User Input; 1.13 Controlling Case; 1.14 Properly Capitalizing a Title or Headline; 1.15 Interpolating Functions and Expressions Within Strings; 1.16 Indenting Here Documents; 1.17 Reformatting Paragraphs; 1.18 Escaping Characters; 1.19 Trimming Blanks from the Ends of a String; 1.20 Parsing Comma-Separated Data; 1.21 Constant Variables; 1.22 Soundex Matching; 1.23 Program: fixstyle; 1.24 Program: psgrep; Chapter 2: Numbers; 2.1 Introduction; 2.1 Checking Whether a String Is a Valid Number; 2.2 Rounding Floating-Point Numbers; 2.3 Comparing Floating-Point Numbers; 2.4 Operating on a Series of Integers; 2.5 Working with Roman Numerals; 2.6 Generating Random Numbers; 2.7 Generating Repeatable Random Number Sequences; 2.8 Making Numbers Even More Random; 2.9 Generating Biased Random Numbers; 2.10 Doing Trigonometry in Degrees, Not Radians; 2.11 Calculating More Trigonometric Functions; 2.12 Taking Logarithms; 2.13 Multiplying Matrices; 2.14 Using Complex Numbers; 2.15 Converting Binary, Octal, and Hexadecimal Numbers; 2.16 Putting Commas in Numbers; 2.17 Printing Correct Plurals; 2.18 Program: Calculating Prime Factors; Chapter 3: Dates and Times; 3.1 Introduction; 3.1 Finding Today's Date; 3.2 Converting DMYHMS to Epoch Seconds; 3.3 Converting Epoch Seconds to DMYHMS; 3.4 Adding to or Subtracting from a Date; 3.5 Difference of Two Dates; 3.6 Day in a Week/Month/Year or Week Number; 3.7 Parsing Dates and Times from Strings; 3.8 Printing a Date; 3.9 High-Resolution Timers; 3.10 Short Sleeps; 3.11 Program: hopdelta; Chapter 4: Arrays; 4.1 Introduction; 4.1 Specifying a List in Your Program; 4.2 Printing a List with Commas; 4.3 Changing Array Size; 4.4 Implementing a Sparse Array; 4.5 Iterating Over an Array; 4.6 Iterating Over an Array by Reference; 4.7 Extracting Unique Elements from a List; 4.8 Finding Elements in One Array but Not Another; 4.9 Computing Union, Intersection, or Difference of Unique Lists; 4.10 Appending One Array to Another; 4.11 Reversing an Array; 4.12 Processing Multiple Elements of an Array; 4.13 Finding the First List Element That Passes a Test; 4.14 Finding All Elements in an Array Matching Certain Criteria; 4.15 Sorting an Array Numerically; 4.16 Sorting a List by Computable Field; 4.17 Implementing a Circular List; 4.18 Randomizing an Array; 4.19 Program: words; 4.20 Program: permute; Chapter 5: Hashes; 5.1 Introduction; 5.1 Adding an Element to a Hash; 5.2 Testing for the Presence of a Key in a Hash; 5.3 Creating a Hash with Immutable Keys or Values; 5.4 Deleting from a Hash; 5.5 Traversing a Hash; 5.6 Printing a Hash; 5.7 Retrieving from a Hash in Insertion Order; 5.8 Hashes with Multiple Values per Key; 5.9 Inverting a Hash; 5.10 Sorting a Hash; 5.11 Merging Hashes; 5.12 Finding Common or Different Keys in Two Hashes; 5.13 Hashing References; 5.14 Presizing a Hash; 5.15 Finding the Most Common Anything; 5.16 Representing Relationships Between Data; 5.17 Program: dutree; Chapter 6: Pattern Matching; 6.1 Introduction; 6.1 Copying and Substituting Simultaneously; 6.2 Matching Letters; 6.3 Matching Words; 6.4 Commenting Regular Expressions; 6.5 Finding the Nth Occurrence of a Match; 6.6 Matching Within Multiple Lines; 6.7 Reading Records with a Separator; 6.8 Extracting a Range of Lines; 6.9 Matching Shell Globs as Regular Expressions; 6.10 Speeding Up Interpolated Matches; 6.11 Testing for a Valid Pattern; 6.12 Honoring Locale Settings in Regular Expressions; 6.13 Approximate Matching; 6.14 Matching from Where the Last Pattern Left Off; 6.15 Greedy and Non-Greedy Matches; 6.16 Detecting Doubled Words; 6.17 Matching Nested Patterns; 6.18 Expressing AND, OR, and NOT in a Single Pattern; 6.19 Matching a Valid Mail Address; 6.20 Matching Abbreviations; 6.21 Program: urlify; 6.22 Program: tcgrep; 6.23 Regular Expression Grab Bag; Chapter 7: File Access; 7.1 Introduction; 7.1 Opening a File; 7.2 Opening Files with Unusual Filenames; 7.3 Expanding Tildes in Filenames; 7.4 Making Perl Report Filenames in Error Messages; 7.5 Storing Filehandles into Variables; 7.6 Writing a Subroutine That Takes Filehandles as Built-ins Do; 7.7 Caching Open Output Filehandles; 7.8 Printing to Many Filehandles Simultaneously; 7.9 Opening and Closing File Descriptors by Number; 7.10 Copying Filehandles; 7.11 Creating Temporary Files; 7.12 Storing a File Inside Your Program Text; 7.13 Storing Multiple Files in the DATA Area; 7.14 Writing a Unix-Style Filter Program; 7.15 Modifying a File in Place with a Temporary File; 7.16 Modifying a File in Place with the -i Switch; 7.17 Modifying a File in Place Without a Temporary File; 7.18 Locking a File; 7.19 Flushing Output; 7.20 Doing Non-Blocking I/O; 7.21 Determining the Number of Unread Bytes; 7.22 Reading from Many Filehandles Without Blocking; 7.23 Reading an Entire Line Without Blocking; 7.24 Program: netlock; 7.25 Program: lockarea; Chapter 8: File Contents; 8.1 Introduction; 8.1 Reading Lines with Continuation Characters; 8.2 Counting Lines (or Paragraphs or Records) in a File; 8.3 Processing Every Word in a File; 8.4 Reading a File Backward by Line or Paragraph; 8.5 Trailing a Growing File; 8.6 Picking a Random Line from a File; 8.7 Randomizing All Lines; 8.8 Reading a Particular Line in a File; 8.9 Processing Variable-Length Text Fields; 8.10 Removing the Last Line of a File; 8.11 Processing Binary Files; 8.12 Using Random-Access I/O; 8.13 Updating a Random-Access File; 8.14 Reading a String from a Binary File; 8.15 Reading Fixed-Length Records; 8.16 Reading Configuration Files; 8.17 Testing a File for Trustworthiness; 8.18 Treating a File as an Array; 8.19 Setting the Default I/O Layers; 8.20 Reading or Writing Unicode from a Filehandle; 8.21 Converting Microsoft Text Files into Unicode; 8.22 Comparing the Contents of Two Files; 8.23 Pretending a String Is a File; 8.24 Program: tailwtmp; 8.25 Program: tctee; 8.26 Program: laston; 8.27 Program: Flat File Indexes; Chapter 9: Directories; 9.1 Introduction; 9.1 Getting and Setting Timestamps; 9.2 Deleting a File; 9.3 Copying or Moving a File; 9.4 Recognizing Two Names for the Same File; 9.5 Processing All Files in a Directory; 9.6 Globbing, or Getting a List of Filenames Matching a Pattern; 9.7 Processing All Files in a Directory Recursively; 9.8 Removing a Directory and Its Contents; 9.9 Renaming Files; 9.10 Splitting a Filename into Its Component Parts; 9.11 Working with Symbolic File Permissions Instead of Octal Values; 9.12 Program: symirror; 9.13 Program: lst; Chapter 10: Subroutines; 10.1 Introduction; 10.1 Accessing Subroutine Arguments; 10.2 Making Variables Private to a Function; 10.3 Creating Persistent Private Variables; 10.4 Determining Current Function Name; 10.5 Passing Arrays and Hashes by Reference; 10.6 Detecting Return Context; 10.7 Passing by Named Parameter; 10.8 Skipping Selected Return Values; 10.9 Returning More Than One Array or Hash; 10.10 Returning Failure; 10.11 Prototyping Functions; 10.12 Handling Exceptions; 10.13 Saving Global Values; 10.14 Redefining a Function; 10.15 Trapping Undefined Function Calls with AUTOLOAD; 10.16 Nesting Subroutines; 10.17 Writing a Switch Statement; 10.18 Program: Sorting Your Mail; Chapter 11: References and Records; 11.1 Introduction; 11.1 Taking References to Arrays; 11.2 Making Hashes of Arrays; 11.3 Taking References to Hashes; 11.4 Taking References to Functions; 11.5 Taking References to Scalars; 11.6 Creating Arrays of Scalar References; 11.7 Using Closures Instead of Objects; 11.8 Creating References to Methods; 11.9 Constructing Records; 11.10 Reading and Writing Hash Records to Text Files; 11.11 Printing Data Structures; 11.12 Copying Data Structures; 11.13 Storing Data Structures to Disk; 11.14 Transparently Persistent Data Structures; 11.15 Coping with Circular Data Structures Using Weak References; 11.16 Program: Outlines; 11.17 Program: Binary Trees; Chapter 12: Packages, Libraries, and Modules; 12.1 Introduction; 12.1 Defining a Module's Interface; 12.2 Trapping Errors in require or use; 12.3 Delaying use Until Runtime; 12.4 Making Variables Private to a Module; 12.5 Making Functions Private to a Module; 12.6 Determining the Caller's Package; 12.7 Automating Module Cleanup; 12.8 Keeping Your Own Module Directory; 12.9 Preparing a Module for Distribution; 12.10 Speeding Module Loading with SelfLoader; 12.11 Speeding Up Module Loading with Autoloader; 12.12 Overriding Built-in Functions; 12.13 Overriding a Built-in Function in All Packages; 12.14 Reporting Errors and Warnings Like Built-ins; 12.15 Customizing Warnings; 12.16 Referring to Packages Indirectly; 12.17 Using h2ph to Translate C #include Files; 12.18 Using h2xs to Make a Module with C Code; 12.19 Writing Extensions in C with Inline::C; 12.20 Documenting Your Module with Pod; 12.21 Building and Installing a CPAN Module; 12.22 Example: Module Template; 12.23 Program: Finding Versions and Descriptions of Installed Modules; Chapter 13: Classes, Objects, and Ties; 13.1 Introduction; 13.1 Constructing an Object; 13.2 Destroying an Object; 13.3 Managing Instance Data; 13.4 Managing Class Data; 13.5 Using Classes as Structs; 13.6 Cloning Constructors; 13.7 Copy Constructors; 13.8 Invoking Methods Indirectly; 13.9 Determining Subclass Membership; 13.10 Writing an Inheritable Class; 13.11 Accessing Overridden Methods; 13.12 Generating Attribute Methods Using AUTOLOAD; 13.13 Coping with Circular Data Structures Using Objects; 13.14 Overloading Operators; 13.15 Creating Magic Variables with tie; Chapter 14: Database Access; 14.1 Introduction; 14.1 Making and Using a DBM File; 14.2 Emptying a DBM File; 14.3 Converting Between DBM Files; 14.4 Merging DBM Files; 14.5 Sorting Large DBM Files; 14.6 Storing Complex Data in a DBM File; 14.7 Persistent Data; 14.8 Saving Query Results to Excel or CSV; 14.9 Executing an SQL Command Using DBI; 14.10 Escaping Quotes; 14.11 Dealing with Database Errors; 14.12 Repeating Queries Efficiently; 14.13 Building Queries Programmatically; 14.14 Finding the Number of Rows Returned by a Query; 14.15 Using Transactions; 14.16 Viewing Data One Page at a Time; 14.17 Querying a CSV File with SQL; 14.18 Using SQL Without a Database Server; 14.19 Program: ggh-Grep Netscape Global History; Chapter 15: Interactivity; 15.1 Introduction; 15.1 Parsing Program Arguments; 15.2 Testing Whether a Program Is Running Interactively; 15.3 Clearing the Screen; 15.4 Determining Terminal or Window Size; 15.5 Changing Text Color; 15.6 Reading Single Characters from the Keyboard; 15.7 Ringing the Terminal Bell; 15.8 Using POSIX termios; 15.9 Checking for Waiting Input; 15.10 Reading Passwords; 15.11 Editing Input; 15.12 Managing the Screen; 15.13 Controlling Another Program with Expect; 15.14 Creating Menus with Tk; 15.15 Creating Dialog Boxes with Tk; 15.16 Responding to Tk Resize Events; 15.17 Removing the DOS Shell Window with Windows Perl/Tk; 15.18 Graphing Data; 15.19 Thumbnailing Images; 15.20 Adding Text to an Image; 15.21 Program: Small termcap Program; 15.22 Program: tkshufflepod; 15.23 Program: graphbox; Chapter 16: Process Management and Communication; 16.1 Introduction; 16.1 Gathering Output from a Program; 16.2 Running Another Program; 16.3 Replacing the Current Program with a Different One; 16.4 Reading or Writing to Another Program; 16.5 Filtering Your Own Output; 16.6 Preprocessing Input; 16.7 Reading STDERR from a Program; 16.8 Controlling Input and Output of Another Program; 16.9 Controlling the Input, Output, and Error of Another Program; 16.10 Communicating Between Related Processes; 16.11 Making a Process Look Like a File with Named Pipes; 16.12 Sharing Variables in Different Processes; 16.13 Listing Available Signals; 16.14 Sending a Signal; 16.15 Installing a Signal Handler; 16.16 Temporarily Overriding a Signal Handler; 16.17 Writing a Signal Handler; 16.18 Catching Ctrl-C; 16.19 Avoiding Zombie Processes; 16.20 Blocking Signals; 16.21 Timing Out an Operation; 16.22 Turning Signals into Fatal Errors; 16.23 Program: sigrand; Chapter 17: Sockets; 17.1 Introduction; 17.1 Writing a TCP Client; 17.2 Writing a TCP Server; 17.3 Communicating over TCP; 17.4 Setting Up a UDP Client; 17.5 Setting Up a UDP Server; 17.6 Using Unix Domain Sockets; 17.7 Identifying the Other End of a Socket; 17.8 Finding Your Own Name and Address; 17.9 Closing a Socket After Forking; 17.10 Writing Bidirectional Clients; 17.11 Forking Servers; 17.12 Pre-Forking Servers; 17.13 Non-Forking Servers; 17.14 Multitasking Server with Threads; 17.15 Writing a Multitasking Server with POE; 17.16 Writing a Multihomed Server; 17.17 Making a Daemon Server; 17.18 Restarting a Server on Demand; 17.19 Managing Multiple Streams of Input; 17.20 Program: backsniff; 17.21 Program: fwdport; Chapter 18: Internet Services; 18.1 Introduction; 18.1 Simple DNS Lookups; 18.2 Being an FTP Client; 18.3 Sending Mail; 18.4 Reading and Posting Usenet News Messages; 18.5 Reading Mail with POP3; 18.6 Simulating Telnet from a Program; 18.7 Pinging a Machine; 18.8 Accessing an LDAP Server; 18.9 Sending Attachments in Mail; 18.10 Extracting Attachments from Mail; 18.11 Writing an XML-RPC Server; 18.12 Writing an XML-RPC Client; 18.13 Writing a SOAP Server; 18.14 Writing a SOAP Client; 18.15 Program: rfrm; 18.16 Program: expn and vrfy; Chapter 19: CGI Programming; 19.1 Introduction; 19.1 Writing a CGI Script; 19.2 Redirecting Error Messages; 19.3 Fixing a 500 Server Error; 19.4 Writing a Safe CGI Program; 19.5 Executing Commands Without Shell Escapes; 19.6 Formatting Lists and Tables with HTML Shortcuts; 19.7 Redirecting to a Different Location; 19.8 Debugging the Raw HTTP Exchange; 19.9 Managing Cookies; 19.10 Creating Sticky Widgets; 19.11 Writing a Multiscreen CGI Script; 19.12 Saving a Form to a File or Mail Pipe; 19.13 Program: chemiserie; Chapter 20: Web Automation; 20.1 Introduction; 20.1 Fetching a URL from a Perl Script; 20.2 Automating Form Submission; 20.3 Extracting URLs; 20.4 Converting ASCII to HTML; 20.5 Converting HTML to ASCII; 20.6 Extracting or Removing HTML Tags; 20.7 Finding Stale Links; 20.8 Finding Fresh Links; 20.9 Using Templates to Generate HTML; 20.10 Mirroring Web Pages; 20.11 Creating a Robot; 20.12 Parsing a Web Server Log File; 20.13 Processing Server Logs; 20.14 Using Cookies; 20.15 Fetching Password-Protected Pages; 20.16 Fetching https:// Web Pages; 20.17 Resuming an HTTP GET; 20.18 Parsing HTML; 20.19 Extracting Table Data; 20.20 Program: htmlsub; 20.21 Program: hrefsub; Chapter 21: mod_perl; 21.1 Introduction; 21.1 Authenticating; 21.2 Setting Cookies; 21.3 Accessing Cookie Values; 21.4 Redirecting the Browser; 21.5 Interrogating Headers; 21.6 Accessing Form Parameters; 21.7 Receiving Uploaded Files; 21.8 Speeding Up Database Access; 21.9 Customizing Apache's Logging; 21.10 Transparently Storing Information in URLs; 21.11 Communicating Between mod_perl and PHP; 21.12 Migrating from CGI to mod_perl; 21.13 Sharing Information Between Handlers; 21.14 Reloading Changed Modules; 21.15 Benchmarking a mod_perl Application; 21.16 Templating with HTML::Mason; 21.17 Templating with Template Toolkit; Chapter 22: XML; 22.1 Introduction; 22.1 Parsing XML into Data Structures; 22.2 Parsing XML into a DOM Tree; 22.3 Parsing XML into SAX Events; 22.4 Making Simple Changes to Elements or Text; 22.5 Validating XML; 22.6 Finding Elements and Text Within an XML Document; 22.7 Processing XML Stylesheet Transformations; 22.8 Processing Files Larger Than Available Memory; 22.9 Reading and Writing RSS Files; 22.10 Writing XML; Colophon;