PERLTOC

perltoc − perl documentation table of contents

This page provides a brief table of contents for the rest of the Perl documentation set. It is meant to be scanned quickly or grepped through to locate the proper section you’re looking for.

perl − Practical Extraction and Report Language

SYNOPSIS

Overview

Tutorials

Reference Manual

Internals and C Language Interface

Miscellaneous

Language-Specific

Platform-Specific

DESCRIPTION

AVAILABILITY

ENVIRONMENT

AUTHOR

FILES

SEE ALSO

DIAGNOSTICS

BUGS

NOTES

perlintro -- a brief introduction and overview of Perl

DESCRIPTION

What is Perl?

Running Perl programs

Safety net

Basic syntax overview

Perl variable types

Scalars, Arrays, Hashes

Variable scoping

Conditional and looping constructs

if, while, for, foreach

Builtin operators and functions

Arithmetic, Numeric comparison, String comparison, Boolean logic, Miscellaneous

Files and I/O

Regular expressions

Simple matching, Simple substitution, More complex regular expressions, Parentheses for capturing, Other regexp features

Writing subroutines

OO Perl

Using Perl modules

AUTHOR

perlreftut − Mark’s very short tutorial about references

DESCRIPTION

Who Needs Complicated Data Structures?

The Solution

Syntax

Making References

Using References

An Example

Arrow Rule

Solution

The Rest

Summary

Credits

Distribution Conditions

perldsc − Perl Data Structures Cookbook

DESCRIPTION

arrays of arrays, hashes of arrays, arrays of hashes, hashes of hashes, more elaborate constructs

REFERENCES

COMMON MISTAKES

CAVEAT ON PRECEDENCE

WHY YOU SHOULD ALWAYS "use strict"

DEBUGGING

CODE EXAMPLES

ARRAYS OF ARRAYS

Declaration of an ARRAY OF ARRAYS

Generation of an ARRAY OF ARRAYS

Access and Printing of an ARRAY OF ARRAYS

HASHES OF ARRAYS

Declaration of a HASH OF ARRAYS

Generation of a HASH OF ARRAYS

Access and Printing of a HASH OF ARRAYS

ARRAYS OF HASHES

Declaration of an ARRAY OF HASHES

Generation of an ARRAY OF HASHES

Access and Printing of an ARRAY OF HASHES

HASHES OF HASHES

Declaration of a HASH OF HASHES

Generation of a HASH OF HASHES

Access and Printing of a HASH OF HASHES

MORE ELABORATE RECORDS

Declaration of MORE ELABORATE RECORDS

Declaration of a HASH OF COMPLEX RECORDS

Generation of a HASH OF COMPLEX RECORDS

Database Ties

SEE ALSO

AUTHOR

perllol − Manipulating Arrays of Arrays in Perl

DESCRIPTION

Declaration and Access of Arrays of Arrays

Growing Your Own

Access and Printing

Slices

SEE ALSO

AUTHOR

perlrequick − Perl regular expressions quick start

DESCRIPTION

The Guide

Simple word matching

Using character classes

Matching this or that

Grouping things and hierarchical matching

Extracting matches

Matching repetitions

More matching

Search and replace

The split operator

BUGS

SEE ALSO

AUTHOR AND COPYRIGHT

Acknowledgments

perlretut − Perl regular expressions tutorial

DESCRIPTION

Part 1: The basics

Simple word matching

Using character classes

Matching this or that

Grouping things and hierarchical matching

Extracting matches

Backreferences

Relative backreferences

Named backreferences

Alternative capture group numbering

Position information

Non-capturing groupings

Matching repetitions

Possessive quantifiers

Building a regexp

Using regular expressions in Perl

Part 2: Power tools

More on characters, strings, and character classes

Compiling and saving regular expressions

Composing regular expressions at runtime

Embedding comments and modifiers in a regular expression

Looking ahead and looking behind

Using independent subexpressions to prevent backtracking

Conditional expressions

Defining named patterns

Recursive patterns

A bit of magic: executing Perl code in a regular expression

Backtracking control verbs

Pragmas and debugging

BUGS

SEE ALSO

AUTHOR AND COPYRIGHT

Acknowledgments

perlboot − Beginner’s Object-Oriented Tutorial

DESCRIPTION

If we could talk to the animals...

Introducing the method invocation arrow

Invoking a barnyard

The extra parameter of method invocation

Calling a second method to simplify things

Inheriting the windpipes

A few notes about @ISA

Overriding the methods

Starting the search from a different place

The SUPER way of doing things

Let’s review...

A horse is a horse, of course of course -- or is it?

Invoking an instance method

Accessing the instance data

How to build a horse

Inheriting the constructor

Making a method work with either classes or instances

Adding parameters to a method

More interesting instances

A horse of a different color

Summary

SEE ALSO

COPYRIGHT

perltoot − Tom’s object-oriented tutorial for perl

DESCRIPTION

Creating a Class

Object Representation

Class Interface

Constructors and Instance Methods

Planning for the Future: Better Constructors

Destructors

Other Object Methods

Class Data

Accessing Class Data

Debugging Methods

Class Destructors

Documenting the Interface

Aggregation

Inheritance

Overridden Methods

Multiple Inheritance

UNIVERSAL: The Root of All Objects

Deeper UNIVERSAL details

Alternate Object Representations

Arrays as Objects

Closures as Objects

AUTOLOAD: Proxy Methods

Autoloaded Data Methods

Inherited Autoloaded Data Methods

Metaclassical Tools

Class::Struct

Data Members as Variables

NOTES

Object Terminology

SEE ALSO

AUTHOR AND COPYRIGHT

COPYRIGHT

Acknowledgments

perltooc − Tom’s OO Tutorial for Class Data in Perl

DESCRIPTION

Class Data in a Can

Class Data as Package Variables

Putting All Your Eggs in One Basket

Inheritance Concerns

The Eponymous Meta-Object

Indirect References to Class Data

Monadic Classes

Translucent Attributes

Class Data as Lexical Variables

Privacy and Responsibility

File-Scoped Lexicals

More Inheritance Concerns

Locking the Door and Throwing Away the Key

Translucency Revisited

NOTES

SEE ALSO

AUTHOR AND COPYRIGHT

ACKNOWLEDGEMENTS

HISTORY

perlbot − Bag’o Object Tricks (the BOT )

DESCRIPTION

OO SCALING TIPS

INSTANCE VARIABLES

SCALAR INSTANCE VARIABLES

INSTANCE VARIABLE INHERITANCE

OBJECT RELATIONSHIPS

OVERRIDING SUPERCLASS METHODS

USING RELATIONSHIP WITH SDBM

THINKING OF CODE REUSE

CLASS CONTEXT AND THE OBJECT

INHERITING A CONSTRUCTOR

DELEGATION

SEE ALSO

perlperf − Perl Performance and Optimization Techniques

DESCRIPTION

OVERVIEW

ONE STEP SIDEWAYS

ONE STEP FORWARD

ANOTHER STEP SIDEWAYS

GENERAL GUIDELINES

BENCHMARKS

Assigning and Dereferencing Variables.

Search and replace or tr

PROFILING TOOLS

Devel::DProf

Devel::Profiler

Devel::SmallProf

Devel::FastProf

Devel::NYTProf

SORTING

Elapsed Real Time, User CPU Time, System CPU Time

LOGGING

Logging if DEBUG (constant)

POSTSCRIPT

SEE ALSO

PERLDOCS

MAN PAGES

MODULES

URLS

AUTHOR

perlstyle − Perl style guide

DESCRIPTION

perlcheat − Perl 5 Cheat Sheet

DESCRIPTION

The sheet

ACKNOWLEDGEMENTS

AUTHOR

SEE ALSO

perltrap − Perl traps for the unwary

DESCRIPTION

Awk Traps

C/C ++ Traps

Sed Traps

Shell Traps

Perl Traps

Perl4 to Perl5 Traps

Discontinuance, Deprecation, and BugFix traps, Parsing Traps, Numerical Traps, General data type traps, Context Traps − scalar, list contexts, Precedence Traps, General Regular Expression Traps using s///, etc, Subroutine, Signal, Sorting Traps, OS Traps, DBM Traps, Unclassified Traps

Discontinuance, Deprecation, and BugFix traps

Symbols starting with "_" no longer forced into main, Double-colon valid package separator in variable name, 2nd and 3rd args to "splice()" are now in scalar context, Can’t do "goto" into a block that is optimized away, Can’t use whitespace as variable name or quote delimiter, "while/if BLOCK BLOCK" gone, "**" binds tighter than unary minus, "foreach" changed when iterating over a list, "split" with no args behavior changed, −e behavior fixed, "push" returns number of elements in resulting list, Some error messages differ, "split()" honors subroutine args, Bugs removed

Parsing Traps

Space between . and = triggers syntax error, Better parsing in perl 5, Function parsing, String interpolation of $#array differs, Perl guesses on "map", "grep" followed by "{" if it starts BLOCK or hash ref

Numerical Traps

Formatted output and significant digits, Auto-increment operator over signed int limit deleted, Assignment of return values from numeric equality tests doesn’t work, Bitwise string ops

General data type traps

Negative array subscripts now count from the end of array, Setting $#array lower now discards array elements, Hashes get defined before use, Glob assignment from localized variable to variable, Assigning "undef" to glob, Changes in unary negation (of strings), Modifying of constants prohibited, "defined $var" behavior changed, Variable Suicide

Context Traps − scalar, list contexts

Elements of argument lists for formats evaluated in list context, "caller()" returns false value in scalar context if no caller present, Comma operator in scalar context gives scalar context to args, "sprintf()" prototyped as "($;@)"

Precedence Traps

LHS vs. RHS of any assignment operator, Semantic errors introduced due to precedence, Precedence of assignment operators same as the precedence of assignment, "open" requires parentheses around filehandle, $: precedence over $:: gone, Precedence of file test operators documented, "keys", "each", "values" are regular named unary operators

General Regular Expression Traps using s///, etc.

"s'$lhs'$rhs'" interpolates on either side, "m//g" attaches its state to the searched string, "m//o" used within an anonymous sub, $+ isn’t set to whole match, Substitution now returns null string if it fails, "s`lhs`rhs`" is now a normal substitution, Stricter parsing of variables in regular expressions, "m?x?" matches only once, Failed matches don’t reset the match variables

Subroutine, Signal, Sorting Traps

Barewords that used to look like strings look like subroutine calls, Reverse is no longer allowed as the name of a sort subroutine, "warn()" won’t let you specify a filehandle

OS Traps

SysV resets signal handler correctly, SysV "seek()" appends correctly

Interpolation Traps

"@" always interpolates an array in double-quotish strings, Double-quoted strings may no longer end with an unescaped $, Arbitrary expressions are evaluated inside braces within double quotes, $$x now tries to dereference $x, Creation of hashes on the fly with "eval "EXPR"" requires protection, Bugs in earlier perl versions, Array and hash brackets during interpolation, Interpolation of "\$$foo{bar}", "qq()" string passed to "eval" will not find string terminator

DBM Traps

Perl5 must have been linked with same dbm/ndbm as the default for "dbmopen()", DBM exceeding limit on the key/value size will cause perl5 to exit immediately

Unclassified Traps

"require"/"do" trap using returned value, "split" on empty string with LIMIT specified

perldebtut − Perl debugging tutorial

DESCRIPTION

use strict

Looking at data and −w and v

help

Stepping through code

Placeholder for a, w, t, T

REGULAR EXPRESSIONS

OUTPUT TIPS

CGI

GUIs

SUMMARY

SEE ALSO

AUTHOR

CONTRIBUTORS

perlfaq − frequently asked questions about Perl

DESCRIPTION

Where to get the perlfaq

How to contribute to the perlfaq

What will happen if you mail your Perl programming problems to the authors?

CREDITS

AUTHOR AND COPYRIGHT

Table of Contents

perlfaq − this document, perlfaq1 − General Questions About Perl, perlfaq2 − Obtaining and Learning about Perl, perlfaq3 − Programming Tools, perlfaq4 − Data Manipulation, perlfaq5 − Files and Formats, perlfaq6 − Regular Expressions, perlfaq7 − General Perl Language Issues, perlfaq8 − System Interaction, perlfaq9 − Networking

The Questions

perlfaq1: General Questions About Perl

perlfaq2: Obtaining and Learning about Perl

perlfaq3: Programming Tools

perlfaq4: Data Manipulation

perlfaq5: Files and Formats

perlfaq6: Regular Expressions

perlfaq7: General Perl Language Issues

perlfaq8: System Interaction

perlfaq9: Networking

perlfaq1 − General Questions About Perl

DESCRIPTION

What is Perl?

Who supports Perl? Who develops it? Why is it free?

Which version of Perl should I use?

What are Perl 4, Perl 5, or Perl 6?

What was Ponie?

What is Perl 6?

How stable is Perl?

Is Perl difficult to learn?

How does Perl compare with other languages like Java, Python, REXX , Scheme, or Tcl?

Can I do [task] in Perl?

When shouldn’t I program in Perl?

What’s the difference between "perl" and "Perl"?

Is it a Perl program or a Perl script?

What is a JAPH ?

Where can I get a list of Larry Wall witticisms?

How can I convince others to use Perl?

http://perltraining.com.au/whyperl.html, http://www.perl.org/advocacy/whyperl.html

REVISION

AUTHOR AND COPYRIGHT

perlfaq2 − Obtaining and Learning about Perl

DESCRIPTION

What machines support perl? Where do I get it?

How can I get a binary version of perl?

I don’t have a C compiler. How can I build my own Perl interpreter?

I copied the perl binary from one machine to another, but scripts don’t work.

I grabbed the sources and tried to compile but gdbm/dynamic loading/malloc/linking/... failed. How do I make it work?

What modules and extensions are available for Perl? What is CPAN ? What does CPAN/src/... mean?

Is there an ISO or ANSI certified version of Perl?

Where can I get information on Perl?

What are the Perl newsgroups on Usenet? Where do I post questions?

Where should I post source code?

Perl Books

References, Tutorials, Task-Oriented, Special Topics

Which magazines have Perl content?

What mailing lists are there for Perl?

Where are the archives for comp.lang.perl.misc?

Where can I buy a commercial version of perl?

Where do I send bug reports?

What is perl.com? Perl Mongers? pm.org? perl.org? cpan.org?

REVISION

AUTHOR AND COPYRIGHT

perlfaq3 − Programming Tools

DESCRIPTION

How do I do (anything)?

How can I use Perl interactively?

Is there a Perl shell?

How do I find which modules are installed on my system?

How do I debug my Perl programs?

How do I profile my Perl programs?

How do I cross-reference my Perl programs?

Is there a pretty-printer (formatter) for Perl?

Is there a ctags for Perl?

Is there an IDE or Windows Perl Editor?

Eclipse, Enginsite, Komodo, Open Perl IDE , OptiPerl, Padre, PerlBuilder, visiPerl+, Visual Perl, Zeus, GNU Emacs, MicroEMACS, XEmacs, Jed, Elvis, Vile, Vim, Codewright, MultiEdit, SlickEdit, ConTEXT, Bash, Ksh, Tcsh, Zsh, Affrus, Alpha, BBEdit and BBEdit Lite

Where can I get Perl macros for vi?

Where can I get perl-mode for emacs?

How can I use curses with Perl?

How can I write a GUI (X, Tk, Gtk, etc.) in Perl?

Tk, Wx, Gtk and Gtk2, Win32::GUI, CamelBones, Qt, Athena

How can I make my Perl program run faster?

How can I make my Perl program take less memory?

Don’t slurp!, Use map and grep selectively, Avoid unnecessary quotes and stringification, Pass by reference, Tie large variables to disk

Is it safe to return a reference to local or lexical data?

How can I free an array or hash so my program shrinks?

How can I make my CGI script more efficient?

How can I hide the source for my Perl program?

How can I compile my Perl program into byte code or C?

How can I get "#!perl" to work on [ MS−DOS ,NT,...]?

Can I write useful Perl programs on the command line?

Why don’t Perl one-liners work on my DOS/Mac/VMS system?

Where can I learn about CGI or Web programming in Perl?

Where can I learn about object-oriented Perl programming?

Where can I learn about linking C with Perl?

I’ve read perlembed, perlguts, etc., but I can’t embed perl in my C program; what am I doing wrong?

When I tried to run my script, I got this message. What does it mean?

What’s MakeMaker?

REVISION

AUTHOR AND COPYRIGHT

perlfaq4 − Data Manipulation

DESCRIPTION

Data: Numbers

Why am I getting long decimals (eg, 19.9499999999999) instead of the numbers I should be getting (eg, 19.95)?

Why is int() broken?

Why isn’t my octal data interpreted correctly?

Does Perl have a round() function? What about ceil() and floor()? Trig functions?

How do I convert between numeric representations/bases/radixes?

How do I convert hexadecimal into decimal, How do I convert from decimal to hexadecimal, How do I convert from octal to decimal, How do I convert from decimal to octal, How do I convert from binary to decimal, How do I convert from decimal to binary

Why doesn’t & work the way I want it to?

How do I multiply matrices?

How do I perform an operation on a series of integers?

How can I output Roman numerals?

Why aren’t my random numbers random?

How do I get a random number between X and Y?

Data: Dates

How do I find the day or week of the year?

How do I find the current century or millennium?

How can I compare two dates and find the difference?

How can I take a string and turn it into epoch seconds?

How can I find the Julian Day?

How do I find yesterday’s date?

Does Perl have a Year 2000 problem? Is Perl Y2K compliant?

Data: Strings

How do I validate input?

How do I unescape a string?

How do I remove consecutive pairs of characters?

How do I expand function calls in a string?

How do I find matching/nesting anything?

How do I reverse a string?

How do I expand tabs in a string?

How do I reformat a paragraph?

How can I access or change N characters of a string?

How do I change the Nth occurrence of something?

How can I count the number of occurrences of a substring within a string?

Does Perl have a Year 2038 problem?

How do I capitalize all the words on one line?

How can I split a [character] delimited string except when inside [character]?

How do I strip blank space from the beginning/end of a string?

How do I pad a string with blanks or pad a number with zeroes?

How do I extract selected columns from a string?

How do I find the soundex value of a string?

How can I expand variables in text strings?

What’s wrong with always quoting "$vars"?

Why don’t my << HERE documents work?

There must be no space after the << part, There (probably) should be a semicolon at the end, You can’t (easily) have any space in front of the tag

Data: Arrays

What is the difference between a list and an array?

What is the difference between $array[1] and @array[1]?

How can I remove duplicate elements from a list or array?

How can I tell whether a certain element is contained in a list or array?

How do I compute the difference of two arrays? How do I compute the intersection of two arrays?

How do I test whether two arrays or hashes are equal?

How do I find the first array element for which a condition is true?

How do I handle linked lists?

How do I handle circular lists?

How do I shuffle an array randomly?

How do I process/modify each element of an array?

How do I select a random element from an array?

How do I permute N elements of a list?

How do I sort an array by (anything)?

How do I manipulate arrays of bits?

Why does defined() return true on empty arrays and hashes?

Data: Hashes (Associative Arrays)

How do I process an entire hash?

How do I merge two hashes?

What happens if I add or remove keys from a hash while iterating over it?

How do I look up a hash element by value?

How can I know how many entries are in a hash?

How do I sort a hash (optionally by value instead of key)?

How can I always keep my hash sorted?

What’s the difference between "delete" and "undef" with hashes?

Why don’t my tied hashes make the defined/exists distinction?

How do I reset an each() operation part-way through?

How can I get the unique keys from two hashes?

How can I store a multidimensional array in a DBM file?

How can I make my hash remember the order I put elements into it?

Why does passing a subroutine an undefined element in a hash create it?

How can I make the Perl equivalent of a C structure/C ++ class/hash or array of hashes or arrays?

How can I use a reference as a hash key?

Data: Misc

How do I handle binary data correctly?

How do I determine whether a scalar is a number/whole/integer/float?

How do I keep persistent data across program calls?

How do I print out or copy a recursive data structure?

How do I define methods for every class/object?

How do I verify a credit card checksum?

How do I pack arrays of doubles or floats for XS code?

REVISION

AUTHOR AND COPYRIGHT

perlfaq5 − Files and Formats

DESCRIPTION

How do I flush/unbuffer an output filehandle? Why must I do this?

How do I change, delete, or insert a line in a file, or append to the beginning of a file?

How do I count the number of lines in a file?

How can I use Perl’s "−i" option from within a program?

How can I copy a file?

How do I make a temporary file name?

How can I manipulate fixed-record-length files?

How can I make a filehandle local to a subroutine? How do I pass filehandles between subroutines? How do I make an array of filehandles?

How can I use a filehandle indirectly?

How can I set up a footer format to be used with write()?

How can I write() into a string?

How can I open a filehandle to a string?

How can I output my numbers with commas added?

How can I translate tildes (~) in a filename?

How come when I open a file read-write it wipes it out?

Why do I sometimes get an "Argument list too long" when I use <*>?

Is there a leak/bug in glob()?

How can I open a file with a leading ">" or trailing blanks?

How can I reliably rename a file?

How can I lock a file?

Why can’t I just open( FH , ">file.lock")?

I still don’t get locking. I just want to increment the number in the file. How can I do this?

All I want to do is append a small amount of text to the end of a file. Do I still have to use locking?

How do I randomly update a binary file?

How do I get a file’s timestamp in perl?

How do I set a file’s timestamp in perl?

How do I print to more than one file at once?

How can I read in an entire file all at once?

How can I read in a file by paragraphs?

How can I read a single character from a file? From the keyboard?

How can I tell whether there’s a character waiting on a filehandle?

How do I do a "tail −f" in perl?

How do I dup() a filehandle in Perl?

How do I close a file descriptor by number?

Why can’t I use "C:\temp\foo" in DOS paths? Why doesn’t ‘C:\temp\foo.exe‘ work?

Why doesn’t glob("*.*") get all the files?

Why does Perl let me delete read-only files? Why does "−i" clobber protected files? Isn’t this a bug in Perl?

How do I select a random line from a file?

Why do I get weird spaces when I print an array of lines?

How do I traverse a directory tree?

How do I delete a directory tree?

How do I copy an entire directory?

AUTHOR AND COPYRIGHT

perlfaq6 − Regular Expressions

DESCRIPTION

How can I hope to use regular expressions without creating illegible and unmaintainable code?

Comments Outside the Regex, Comments Inside the Regex, Different Delimiters

I’m having trouble matching over more than one line. What’s wrong?

How can I pull out lines between two patterns that are themselves on different lines?

How do I match XML , HTML , or other nasty, ugly things with a regex?

Solve the balanced text problem from another question in perlfaq6, Try the recursive regex features in Perl 5.10 and later. See perlre, Try defining a grammar using Perl 5.10’s "(?DEFINE)" feature, Break the problem down into sub-problems instead of trying to use a single regex, Convince everyone not to use XML or HTML in the first place

I put a regular expression into $/ but it didn’t work. What’s wrong?

How do I substitute case insensitively on the LHS while preserving case on the RHS ?

How can I make "\w" match national character sets?

How can I match a locale-smart version of "/[a−zA−Z]/"?

How can I quote a variable to use in a regex?

What is "/o" really for?

How do I use a regular expression to strip C style comments from a file?

Can I use Perl regular expressions to match balanced text?

What does it mean that regexes are greedy? How can I get around it?

How do I process each word on each line?

How can I print out a word-frequency or line-frequency summary?

How can I do approximate matching?

How do I efficiently match many regular expressions at once?

Why don’t word-boundary searches with "\b" work for me?

Why does using $&, $‘, or $’ slow my program down?

What good is "\G" in a regular expression?

Are Perl regexes DFAs or NFAs? Are they POSIX compliant?

What’s wrong with using grep in a void context?

How can I match strings with multibyte characters?

Martian"

How do I match a regular expression that’s in a variable? ,

REVISION

AUTHOR AND COPYRIGHT

perlfaq7 − General Perl Language Issues

DESCRIPTION

Can I get a BNF/yacc/RE for the Perl language?

What are all these $@%&* punctuation signs, and how do I know when to use them?

Do I always/never have to quote my strings or use semicolons and commas?

How do I skip some return values?

How do I temporarily block warnings?

What’s an extension?

Why do Perl operators have different precedence than C operators?

How do I declare/create a structure?

How do I create a module?

How do I adopt or take over a module already on CPAN ?

How do I create a class?

How can I tell if a variable is tainted?

What’s a closure?

What is variable suicide and how can I prevent it?

How can I pass/return a {Function, FileHandle, Array, Hash, Method, Regex}?

Passing Variables and Functions, Passing Filehandles, Passing Regexes, Passing Methods

How do I create a static variable?

What’s the difference between dynamic and lexical (static) scoping? Between local() and my()?

How can I access a dynamic variable while a similarly named lexical is in scope?

What’s the difference between deep and shallow binding?

Why doesn’t "my($foo) = < FILE >;" work right?

How do I redefine a builtin function, operator, or method?

What’s the difference between calling a function as &foo and foo()?

How do I create a switch or case statement?

How can I catch accesses to undefined variables, functions, or methods?

Why can’t a method included in this same file be found?

How can I find out my current or calling package?

How can I comment out a large block of Perl code?

How do I clear a package?

How can I use a variable as a variable name?

What does "bad interpreter" mean?

REVISION

AUTHOR AND COPYRIGHT

perlfaq8 − System Interaction

DESCRIPTION

How do I find out which operating system I’m running under?

How come exec() doesn’t return?

How do I do fancy stuff with the keyboard/screen/mouse?

Keyboard, Screen, Mouse

How do I print something out in color?

How do I read just one key without waiting for a return key?

How do I check whether input is ready on the keyboard?

How do I clear the screen?

How do I get the screen size?

How do I ask the user for a password?

How do I read and write the serial port?

lockfiles, open mode, end of line, flushing output, non-blocking input

How do I decode encrypted password files?

How do I start a process in the background?

STDIN , STDOUT , and STDERR are shared, Signals, Zombies

How do I trap control characters/signals?

How do I modify the shadow password file on a Unix system?

How do I set the time and date?

How can I sleep() or alarm() for under a second?

How can I measure time under a second?

How can I do an atexit() or setjmp()/longjmp()? (Exception handling)

Why doesn’t my sockets program work under System V (Solaris)? What does the error message "Protocol not supported" mean?

How can I call my system’s unique C functions from Perl?

Where do I get the include files to do ioctl() or syscall()?

Why do setuid perl scripts complain about kernel problems?

How can I open a pipe both to and from a command?

Why can’t I get the output of a command with system()?

How can I capture STDERR from an external command?

Why doesn’t open() return an error when a pipe open fails?

What’s wrong with using backticks in a void context?

How can I call backticks without shell processing?

Why can’t my script read from STDIN after I gave it EOF (^D on Unix, ^Z on MS-DOS)?

How can I convert my shell script to perl?

Can I use perl to run a telnet or ftp session?

How can I write expect in Perl?

Is there a way to hide perl’s command line from programs such as "ps"?

How come the change disappeared when I exited the script? How do I get my changes to be visible?

Unix

How do I close a process’s filehandle without waiting for it to complete?

How do I fork a daemon process?

How do I find out if I’m running interactively or not?

How do I timeout a slow event?

How do I set CPU limits?

How do I avoid zombies on a Unix system?

How do I use an SQL database?

How do I make a system() exit on control-C?

How do I open a file without blocking?

How do I tell the difference between errors from the shell and perl?

How do I install a module from CPAN ?

What’s the difference between require and use?

How do I keep my own module/library directory?

How do I add the directory my program lives in to the module/library search path?

How do I add a directory to my include path (@INC) at runtime?

the PERLLIB environment variable, the PERL5LIB environment variable, the perl −Idir command line flag, the use lib pragma:

What is socket.ph and where do I get it?

REVISION

AUTHOR AND COPYRIGHT

perlfaq9 − Networking

DESCRIPTION

What is the correct form of response from a CGI script?

My CGI script runs from the command line but not the browser. (500 Server Error)

How can I get better error messages from a CGI program?

How do I remove HTML from a string?

How do I extract URLs?

How do I download a file from the user’s machine? How do I open a file on another machine?

How do I make an HTML pop-up menu with Perl?

How do I fetch an HTML file?

How do I automate an HTML form submission?

How do I decode or create those %−encodings on the web?

How do I redirect to another page?

How do I put a password on my web pages?

How do I edit my .htpasswd and .htgroup files with Perl?

How do I make sure users can’t enter values into a form that cause my CGI script to do bad things?

How do I parse a mail header?

How do I decode a CGI form?

How do I check a valid mail address?

How do I decode a MIME/BASE64 string?

How do I return the user’s mail address?

How do I send mail?

How do I use MIME to make an attachment to a mail message?

How do I read mail?

How do I find out my hostname, domainname, or IP address?

gethostbyname, Socket, Net::Domain, Sys::Hostname"

How do I fetch a news article or the active newsgroups?

How do I fetch/put an FTP file?

How can I do RPC in Perl?

REVISION

AUTHOR AND COPYRIGHT

perlsyn − Perl syntax

DESCRIPTION

Declarations

Comments

Simple Statements

Truth and Falsehood

Statement Modifiers

Compound Statements

Loop Control

For Loops

Foreach Loops

Basic BLOCKs

Switch statements

Goto

PODs: Embedded Documentation

Plain Old Comments (Not!)

perldata − Perl data types

DESCRIPTION

Variable names

Context

Scalar values

Scalar value constructors

List value constructors

Subscripts

Slices

Typeglobs and Filehandles

SEE ALSO

perlop − Perl operators and precedence

DESCRIPTION

Operator Precedence and Associativity

Terms and List Operators (Leftward)

The Arrow Operator

Auto-increment and Auto-decrement

Exponentiation

Symbolic Unary Operators

Binding Operators

Multiplicative Operators

Additive Operators

Shift Operators

Named Unary Operators

Relational Operators

Equality Operators

Bitwise And

Bitwise Or and Exclusive Or

C−style Logical And

C−style Logical Or

C−style Logical Defined-Or

Range Operators

Conditional Operator

Assignment Operators

Comma Operator

List Operators (Rightward)

Logical Not

Logical And

Logical or, Defined or, and Exclusive Or

C Operators Missing From Perl

unary &, unary *, ( TYPE )

Quote and Quote-like Operators

Regexp Quote-Like Operators

qr/STRING/msixpo , m/PATTERN/msixpogc , /PATTERN/msixpogc, The empty pattern //, Matching in list context, \G assertion, ?PATTERN? , s/PATTERN/REPLACEMENT/msixpogce

Quote-Like Operators

q/STRING/ , ’ STRING ’, qq/STRING/ , " STRING ", qx/STRING/ , ‘STRING‘, qw/STRING/ , tr/SEARCHLIST/REPLACEMENTLIST/cds , y/SEARCHLIST/REPLACEMENTLIST/cds, << EOF , Double Quotes, Single Quotes, Backticks

Gory details of parsing quoted constructs

Finding the end, Interpolation , "<<'EOF'", "m''", the pattern of "s'''", '', "q//", "tr'''", "y'''", the replacement of "s'''", "tr///", "y///", "", "``", "qq//", "qx//", "<file*glob>", "<<"EOF"", the replacement of "s///", "RE" in "?RE?", "/RE/", "m/RE/", "s/RE/foo/",, parsing regular expressions , Optimization of regular expressions

I/O Operators

Constant Folding

No-ops

Bitwise String Operators

Integer Arithmetic

Floating-point Arithmetic

Bigger Numbers

perlsub − Perl subroutines

SYNOPSIS

DESCRIPTION

Private Variables via my()

Persistent Private Variables

static closure"

Temporary Values via local()

Lvalue subroutines

Lvalue subroutines are EXPERIMENTAL

Passing Symbol Table Entries (typeglobs)

When to Still Use local()

Pass by Reference

Prototypes

Constant Functions

Overriding Built-in Functions

Autoloading

Subroutine Attributes

SEE ALSO

perlfunc − Perl builtin functions

DESCRIPTION

Perl Functions by Category

Functions for SCALARs or strings , Regular expressions and pattern matching , Numeric functions , Functions for real @ARRAYs , Functions for list data , Functions for real %HASHes , Input and output functions , Functions for fixed length data or records, Functions for filehandles, files, or directories , Keywords related to the control flow of your Perl program , Keywords related to switch, Keywords related to scoping, Miscellaneous functions, Functions for processes and process groups , Keywords related to perl modules , Keywords related to classes and object-orientation , Low-level socket functions , System V interprocess communication functions , Fetching user and group info , Fetching network info , Time-related functions , Functions new in perl5 , Functions obsoleted in perl5

Portability

Alphabetical Listing of Perl Functions

−X FILEHANDLE

, −X EXPR , −X DIRHANDLE , −X, abs VALUE , abs, accept NEWSOCKET ,GENERICSOCKET , alarm SECONDS , alarm, atan2 Y,X , bind SOCKET ,NAME , binmode FILEHANDLE , LAYER , binmode FILEHANDLE , bless REF ,CLASSNAME , bless REF , break, caller EXPR , caller, chdir EXPR , chdir FILEHANDLE , chdir DIRHANDLE , chdir, chmod LIST , chomp VARIABLE , chomp( LIST ), chomp, chop VARIABLE , chop( LIST ), chop, chown LIST , chr NUMBER , chr, chroot FILENAME , chroot, close FILEHANDLE , close, closedir DIRHANDLE , connect SOCKET ,NAME , continue BLOCK , continue, cos EXPR , cos, crypt PLAINTEXT ,SALT

, dbmclose HASH , dbmopen HASH ,DBNAME,MASK , defined EXPR , defined, delete EXPR , die LIST , do BLOCK , do SUBROUTINE ( LIST ) , do EXPR , dump LABEL , dump, each HASH , eof FILEHANDLE , eof (), eof, eval EXPR

, eval BLOCK , eval, exec LIST , exec PROGRAM LIST , exists EXPR , exit EXPR , exit, exp EXPR , exp, fcntl FILEHANDLE ,FUNCTION,SCALAR , fileno FILEHANDLE , flock FILEHANDLE ,OPERATION , fork , format , formline PICTURE ,LIST , getc FILEHANDLE , getc, getlogin , getpeername SOCKET , getpgrp PID , getppid , getpriority WHICH ,WHO , getpwnam NAME

, getgrnam NAME , gethostbyname NAME , getnetbyname NAME , getprotobyname NAME , getpwuid UID , getgrgid GID , getservbyname NAME ,PROTO, gethostbyaddr ADDR ,ADDRTYPE, getnetbyaddr ADDR ,ADDRTYPE, getprotobynumber NUMBER , getservbyport PORT ,PROTO, getpwent, getgrent, gethostent, getnetent, getprotoent, getservent, setpwent, setgrent, sethostent STAYOPEN , setnetent STAYOPEN , setprotoent STAYOPEN , setservent STAYOPEN , endpwent, endgrent, endhostent, endnetent, endprotoent, endservent, getsockname SOCKET , getsockopt SOCKET ,LEVEL,OPTNAME , glob EXPR , glob, gmtime EXPR , gmtime, goto LABEL , goto EXPR , goto &NAME, grep BLOCK LIST , grep EXPR ,LIST, hex EXPR , hex, import LIST , index STR ,SUBSTR,POSITION , index STR ,SUBSTR, int EXPR , int, ioctl FILEHANDLE ,FUNCTION,SCALAR , join EXPR ,LIST , keys HASH , kill SIGNAL , LIST , last LABEL , last, lc EXPR , lc, lcfirst EXPR , lcfirst, length EXPR , length, link OLDFILE ,NEWFILE , listen SOCKET ,QUEUESIZE , local EXPR , localtime EXPR , localtime, lock THING , log EXPR , log, lstat EXPR , lstat, m//, map BLOCK LIST , map EXPR ,LIST, mkdir FILENAME ,MASK , mkdir FILENAME , mkdir, msgctl ID ,CMD,ARG , msgget KEY ,FLAGS , msgrcv ID ,VAR,SIZE,TYPE,FLAGS , msgsnd ID ,MSG,FLAGS , my EXPR , my TYPE EXPR , my EXPR : ATTRS , my TYPE EXPR : ATTRS , next LABEL , next, no Module VERSION LIST , no Module VERSION , no Module LIST , no Module, no VERSION , oct EXPR , oct, open FILEHANDLE ,EXPR , open FILEHANDLE ,MODE,EXPR, open FILEHANDLE ,MODE,EXPR,LIST, open FILEHANDLE ,MODE,REFERENCE, open FILEHANDLE , opendir DIRHANDLE ,EXPR , ord EXPR , ord, our EXPR , our TYPE EXPR , our EXPR : ATTRS , our TYPE EXPR : ATTRS , pack TEMPLATE ,LIST , package NAMESPACE , package, pipe READHANDLE ,WRITEHANDLE , pop ARRAY , pop, pos SCALAR , pos, print FILEHANDLE LIST , print LIST , print, printf FILEHANDLE FORMAT , LIST , printf FORMAT , LIST , prototype FUNCTION , push ARRAY ,LIST , q/STRING/, qq/STRING/, qx/STRING/, qw/STRING/, qr/STRING/, quotemeta EXPR , quotemeta, rand EXPR , rand, read FILEHANDLE ,SCALAR,LENGTH,OFFSET , read FILEHANDLE ,SCALAR,LENGTH, readdir DIRHANDLE , readline EXPR , readline , readlink EXPR , readlink, readpipe EXPR , readpipe , recv SOCKET ,SCALAR,LENGTH,FLAGS , redo LABEL , redo, ref EXPR , ref, rename OLDNAME ,NEWNAME , require VERSION , require EXPR , require, reset EXPR , reset, return EXPR , return, reverse LIST , rewinddir DIRHANDLE , rindex STR ,SUBSTR,POSITION , rindex STR ,SUBSTR, rmdir FILENAME , rmdir, s///, say FILEHANDLE LIST , say LIST , say, scalar EXPR , seek FILEHANDLE ,POSITION,WHENCE , seekdir DIRHANDLE ,POS , select FILEHANDLE , select, select RBITS ,WBITS,EBITS,TIMEOUT , semctl ID ,SEMNUM,CMD,ARG , semget KEY ,NSEMS,FLAGS , semop KEY ,OPSTRING , send SOCKET ,MSG,FLAGS,TO , send SOCKET ,MSG,FLAGS, setpgrp PID ,PGRP , setpriority WHICH ,WHO,PRIORITY , setsockopt SOCKET ,LEVEL,OPTNAME,OPTVAL , shift ARRAY , shift, shmctl ID ,CMD,ARG , shmget KEY ,SIZE,FLAGS , shmread ID ,VAR,POS,SIZE , shmwrite ID ,STRING,POS,SIZE, shutdown SOCKET ,HOW , sin EXPR , sin, sleep EXPR , sleep, socket SOCKET ,DOMAIN,TYPE,PROTOCOL , socketpair SOCKET1 ,SOCKET2,DOMAIN,TYPE,PROTOCOL , sort SUBNAME LIST , sort BLOCK LIST , sort LIST , splice ARRAY ,OFFSET,LENGTH,LIST , splice ARRAY ,OFFSET,LENGTH, splice ARRAY ,OFFSET, splice ARRAY , split /PATTERN/,EXPR,LIMIT , split /PATTERN/,EXPR, split /PATTERN/, split, sprintf FORMAT , LIST , format parameter index, flags, vector flag, (minimum) width, precision, or maximum width , size, order of arguments, sqrt EXPR , sqrt, srand EXPR , srand, stat FILEHANDLE , stat EXPR , stat DIRHANDLE , stat, state EXPR , state TYPE EXPR , state EXPR : ATTRS , state TYPE EXPR : ATTRS , study SCALAR , study, sub NAME BLOCK , sub NAME ( PROTO ) BLOCK , sub NAME : ATTRS BLOCK , sub NAME ( PROTO ) : ATTRS BLOCK , substr EXPR ,OFFSET,LENGTH,REPLACEMENT , substr EXPR ,OFFSET,LENGTH, substr EXPR ,OFFSET, symlink OLDFILE ,NEWFILE , syscall NUMBER , LIST , sysopen FILEHANDLE ,FILENAME,MODE , sysopen FILEHANDLE ,FILENAME,MODE,PERMS, sysread FILEHANDLE ,SCALAR,LENGTH,OFFSET , sysread FILEHANDLE ,SCALAR,LENGTH, sysseek FILEHANDLE ,POSITION,WHENCE , system LIST , system PROGRAM LIST , syswrite FILEHANDLE ,SCALAR,LENGTH,OFFSET , syswrite FILEHANDLE ,SCALAR,LENGTH, syswrite FILEHANDLE ,SCALAR, tell FILEHANDLE , tell, telldir DIRHANDLE , tie VARIABLE ,CLASSNAME,LIST , tied VARIABLE , time , times , tr///, truncate FILEHANDLE ,LENGTH , truncate EXPR ,LENGTH, uc EXPR , uc, ucfirst EXPR , ucfirst, umask EXPR , umask, undef EXPR , undef, unlink LIST , unlink, unpack TEMPLATE ,EXPR , unpack TEMPLATE , untie VARIABLE , unshift ARRAY ,LIST , use Module VERSION LIST , use Module VERSION , use Module LIST , use Module, use VERSION , utime LIST , values HASH , vec EXPR ,OFFSET,BITS , wait , waitpid PID ,FLAGS , wantarray , warn LIST , write FILEHANDLE , write EXPR , write, y/// position seekdir select filehandle, default select semctl semget semop send setpgrp group setpriority priority nice renice setsockopt shift shmctl shmget shmread shmwrite shutdown sin sine asin arcsine sleep pause socket socketpair sort qsort quicksort mergesort splice split sprintf precision sqrt root square root srand seed randseed stat file, status ctime state study sub substr substring mid left right symlink link symbolic link link, symbolic syscall system call sysopen sysread sysseek lseek system shell syswrite tell telldir tie tied time epoch times truncate uc uppercase toupper ucfirst uppercase umask undef undefine unlink delete remove rm del unpack untie unshift use module import utime values vec bit bit vector wait waitpid wantarray context warn warning STDERR write"

perlopentut − tutorial on opening things in Perl

DESCRIPTION

Open a la shell

Simple Opens

Indirect Filehandles

Pipe Opens

The Minus File

Mixing Reads and Writes

Filters

Open a la C

Permissions a la mode

Obscure Open Tricks

Re-Opening Files (dups)

Dispelling the Dweomer

Paths as Opens

Single Argument Open

Playing with STDIN and STDOUT

Other I/O Issues

Opening Non-File Files

Opening Named Pipes

Opening Sockets

Binary Files

File Locking

IO Layers

SEE ALSO

AUTHOR and COPYRIGHT

HISTORY

perlpacktut − tutorial on "pack" and "unpack"

DESCRIPTION

The Basic Principle

Packing Text

Packing Numbers

Integers

Unpacking a Stack Frame

How to Eat an Egg on a Net

Byte-order modifiers

Floating point Numbers

Exotic Templates

Bit Strings

Uuencoding

Doing Sums

Unicode

Another Portable Binary Encoding

Template Grouping

Lengths and Widths

String Lengths

Dynamic Templates

Counting Repetitions

Intel HEX

Packing and Unpacking C Structures

The Alignment Pit

Dealing with Endian-ness

Alignment, Take 2

Alignment, Take 3

Pointers for How to Use Them

Pack Recipes

Funnies Section

Authors

perlpod − the Plain Old Documentation format

DESCRIPTION

Ordinary Paragraph

Verbatim Paragraph

Command Paragraph

"=head1 Heading Text" , "=head2 Heading Text", "=head3 Heading Text", "=head4 Heading Text", "=over indentlevel" , "=item stuff...", "=back", "=cut" , "=pod" , "=begin formatname" , "=end formatname", "=for formatname text...", "=encoding encodingname"

Formatting Codes

"I<text>" -- italic text , "B<text>" -- bold text , "C<code>" -- code text , "L<name>" -- a hyperlink , "E<escape>" -- a character escape , "F<filename>" -- used for filenames , "S<text>" -- text contains non-breaking spaces , "X<topic name>" -- an index entry , "Z<>" -- a null (zero-effect) formatting code code, italic italic B BZ<><> POD, formatting code, bold bold C CZ<><> POD, formatting code, code code L LZ<><> POD, formatting code, hyperlink hyperlink E EZ<><> POD, formatting code, escape escape F FZ<><> POD, formatting code, filename filename S SZ<><> POD, formatting code, non-breaking space non-breaking space X XZ<><> POD, formatting code, index entry index entry Z ZZ<><> POD, formatting code, null null"

The Intent

Embedding Pods in Perl Modules

Hints for Writing Pod

SEE ALSO

AUTHOR

perlpodspec − Plain Old Documentation: format specification and notes

DESCRIPTION

Pod Definitions

Pod Commands

"=head1", "=head2", "=head3", "=head4", "=pod", "=cut", "=over", "=item", "=back", "=begin formatname", "=begin formatname parameter", "=end formatname", "=for formatname text...", "=encoding encodingname"

Pod Formatting Codes

"I<text>" -- italic text, "B<text>" -- bold text, "C<code>" -- code text, "F<filename>" -- style for filenames, "X<topic name>" -- an index entry, "Z<>" -- a null (zero-effect) formatting code, "L<name>" -- a hyperlink, "E<escape>" -- a character escape, "S<text>" -- text contains non-breaking spaces

Notes on Implementing Pod Processors

About L<...> Codes

First:, Second:, Third:, Fourth:, Fifth:, Sixth:

About =over...=back Regions

About Data Paragraphs and "=begin/=end" Regions

SEE ALSO

AUTHOR

perlrun − how to execute the Perl interpreter

SYNOPSIS

DESCRIPTION

#! and quoting on non-Unix systems

OS/2 , MS-DOS, Win95/NT, Macintosh, VMS

Location of Perl

Command Switches

−0[octal/hexadecimal] , −a , −C [number/list] , −c , −d , −dt, −d:foo[=bar,baz] , −dt:foo[=bar,baz], −Dletters , −Dnumber, −e commandline , −E commandline , −f , −Fpattern , −h , −i[extension] , −Idirectory , −l[octnum] , −m[−]module , −M[−]module, −M[−]’module ...’, −[mM][−]module=arg[,arg]..., −n , −p , −P , −s , −S , −t , −T , −u , −U , −v , −V , −V:configvar, −w , −W , −X , −x , −xdirectory

ENVIRONMENT

HOME , LOGDIR , PATH , PERL5LIB , PERL5OPT , PERLIO , :bytes , :crlf , :mmap , :perlio , :pop , :raw , :stdio , :unix , :utf8 , :win32 , PERLIO_DEBUG , PERLLIB , PERL5DB , PERL5DB_THREADED , PERL5SHELL (specific to the Win32 port) , PERL_ALLOW_NON_IFS_LSP (specific to the Win32 port) , PERL_DEBUG_MSTATS , PERL_DESTRUCT_LEVEL , PERL_DL_NONLAZY , PERL_ENCODING , PERL_HASH_SEED , PERL_HASH_SEED_DEBUG , PERL_ROOT (specific to the VMS port) , PERL_SIGNALS , PERL_UNICODE , SYS$LOGIN (specific to the VMS port)

perldiag − various Perl diagnostics

DESCRIPTION

SEE ALSO

perllexwarn − Perl Lexical Warnings

DESCRIPTION

Default Warnings and Optional Warnings

What’s wrong with −w and $^W

Controlling Warnings from the Command Line

−w , −W , −X

Backward Compatibility

Category Hierarchy

Fatal Warnings

Reporting Warnings from a Module

SEE ALSO

AUTHOR

perldebug − Perl debugging

DESCRIPTION

The Perl Debugger

Calling the debugger

perl −d program_name, perl −d −e 0, perl −d:Ptkdb program_name, perl −dt threaded_program_name

Debugger Commands

h , h [command], h h, p expr , x [maxdepth] expr , V [pkg [vars]] , X [vars] , y [level [vars]] , T , s [expr] , n [expr] , r , < CR >, c [line|sub] , l , l min+incr, l min-max, l line, l subname, − , v [line] , . , f filename , /pattern/, ?pattern?, L [abw] , S [[!]regex] , t , t expr , b , b [line] [condition] , b subname [condition] , b postpone subname [condition] , b load filename , b compile subname , B line , B * , a [line] command , A line , A * , w expr , W expr , W * , o , o booloption ... , o anyoption? ... , o option=value ... , < ? , < [ command ] , < * , << command , > ? , > command , > * , >> command , { ? , { [ command ], { * , {{ command , ! number , ! −number , ! pattern , !! cmd , source file , H −number , q or ^D , R , |dbcmd , ||dbcmd , command, m expr , M , man [manpage] command, V debugger command, X debugger command, y debugger command, T backtrace stack, backtrace debugger command, s step debugger command, n debugger command, r debugger command, c debugger command, l debugger command, - debugger command, v debugger command, . debugger command, f debugger command, L debugger command, S debugger command, t debugger command, t breakpoint debugger command, b breakpoint debugger command, b breakpoint debugger command, b breakpoint debugger command, b breakpoint debugger command, b breakpoint debugger command, b breakpoint debugger command, B breakpoint debugger command, B debugger command, a debugger command, A debugger command, A debugger command, w debugger command, W debugger command, W debugger command, o debugger command, o debugger command, o debugger command, o debugger command, < debugger command, < debugger command, < debugger command, << debugger command, > debugger command, > debugger command, > debugger command, >> debugger command, { debugger command, { debugger command, {{ debugger command, ! debugger command, ! debugger command, ! debugger command, !! debugger command, source debugger command, H debugger command, q debugger command, ^D debugger command, R debugger command, | debugger command, || debugger command, m debugger command, M debugger command, man"

Configurable Options

"recallCommand", "ShellBang" , "pager" , "tkRunning" , "signalLevel", "warnLevel", "dieLevel" , "AutoTrace" , "LineInfo" , "inhibit_exit" , "PrintRet" , "ornaments" , "frame" , "maxTraceLen" , "windowSize" , "arrayDepth", "hashDepth" , "dumpDepth" , "compactDump", "veryCompact" , "globPrint" , "DumpDBFiles" , "DumpPackages" , "DumpReused" , "quote", "HighBit", "undefPrint" , "UsageOnly" , "TTY" , "noTTY" , "ReadLine" , "NonStop" option, ShellBang debugger option, pager debugger option, tkRunning debugger option, signalLevel debugger option, warnLevel debugger option, dieLevel debugger option, AutoTrace debugger option, LineInfo debugger option, inhibit_exit debugger option, PrintRet debugger option, ornaments debugger option, frame debugger option, maxTraceLen debugger option, windowSize debugger option, arrayDepth debugger option, hashDepth debugger option, dumpDepth debugger option, compactDump debugger option, veryCompact debugger option, globPrint debugger option, DumpDBFiles debugger option, DumpPackages debugger option, DumpReused debugger option, quote debugger option, HighBit debugger option, undefPrint debugger option, UsageOnly debugger option, TTY debugger option, noTTY debugger option, ReadLine debugger option, NonStop"

Debugger input/output

Prompt, Multiline commands, Stack backtrace , Line Listing Format, Frame listing backtrace"

Debugging compile-time statements

Debugger Customization

Readline Support / History in the debugger

Editor Support for Debugging

The Perl Profiler

Debugging regular expressions

Debugging memory usage

SEE ALSO

BUGS

perlvar − Perl predefined variables

DESCRIPTION

Predefined Names

$ARG, $_ , $a, $b , $<digits> , $MATCH, $& , ${^MATCH} , $PREMATCH, "$`" , ${^PREMATCH} , $POSTMATCH, "$'" , ${^POSTMATCH} , $LAST_PAREN_MATCH, $+ , $LAST_SUBMATCH_RESULT, $^N , @LAST_MATCH_END, @+ , %LAST_PAREN_MATCH, %+ , HANDLE− >input_line_number( EXPR ), $INPUT_LINE_NUMBER, $NR, $. , IO::Handle−>input_record_separator( EXPR ), $INPUT_RECORD_SEPARATOR, $RS, $/ , HANDLE− >autoflush( EXPR ), $OUTPUT_AUTOFLUSH, $| , IO::Handle−>output_field_separator EXPR , $OUTPUT_FIELD_SEPARATOR, $OFS, $, , IO::Handle−>output_record_separator EXPR , $OUTPUT_RECORD_SEPARATOR, $ORS, $\ , $LIST_SEPARATOR, $" , $SUBSCRIPT_SEPARATOR, $SUBSEP, $; , HANDLE− >format_page_number( EXPR ), $FORMAT_PAGE_NUMBER, $% , HANDLE− >format_lines_per_page( EXPR ), $FORMAT_LINES_PER_PAGE, $= , HANDLE− >format_lines_left( EXPR ), $FORMAT_LINES_LEFT, $− , @LAST_MATCH_START, @− , "$`" is the same as "substr($var, 0, $−[0])", $& is the same as "substr($var, $−[0], $+[0] − $−[0])", "$'" is the same as "substr($var, $+[0])", $1 is the same as "substr($var, $−[1], $+[1] − $−[1])", $2 is the same as "substr($var, $−[2], $+[2] − $−[2])", $3 is the same as "substr($var, $−[3], $+[3] − $−[3])", %− , HANDLE− >format_name( EXPR ), $FORMAT_NAME, $~ , HANDLE− >format_top_name( EXPR ), $FORMAT_TOP_NAME, $^ , IO::Handle−>format_line_break_characters EXPR , $FORMAT_LINE_BREAK_CHARACTERS, $: , IO::Handle−>format_formfeed EXPR , $FORMAT_FORMFEED, $^L , $ACCUMULATOR, $^A , $CHILD_ERROR, $? , ${^CHILD_ERROR_NATIVE} , ${^ENCODING} , $OS_ERROR, $ERRNO, $! , %OS_ERROR, %ERRNO, %! , $EXTENDED_OS_ERROR, $^E , $EVAL_ERROR, $@ , $PROCESS_ID, $PID, $$ , $REAL_USER_ID, $UID, $< , $EFFECTIVE_USER_ID, $EUID, $> , $REAL_GROUP_ID, $GID, $( , $EFFECTIVE_GROUP_ID, $EGID, $) , $PROGRAM_NAME, $0 , $[ , $] , $COMPILING, $^C , $DEBUGGING, $^D , ${^RE_DEBUG_FLAGS}, ${^RE_TRIE_MAXBUF}, $SYSTEM_FD_MAX, $^F , $^H, %^H, $INPLACE_EDIT, $^I , $^M , $OSNAME, $^O , ${^OPEN}, $PERLDB, $^P , 0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x100, 0x200, 0x400, $LAST_REGEXP_CODE_RESULT, $^R , $EXCEPTIONS_BEING_CAUGHT, $^S , $BASETIME, $^T , ${^TAINT}, ${^UNICODE}, ${^UTF8CACHE}, ${^UTF8LOCALE}, $PERL_VERSION, $^V , $WARNING, $^W , ${^WARNING_BITS}, ${^WIN32_SLOPPY_STAT}, $EXECUTABLE_NAME, $^X , ARGV , $ARGV , @ARGV , ARGVOUT , @F , @INC , @ARG, @_ , %INC , %ENV, $ENV{expr} , %SIG, $SIG{expr}

Error Indicators

Technical Note on the Syntax of Variable Names

BUGS

perlre − Perl regular expressions

DESCRIPTION

Modifiers

m , s , i , x , p , g and c multiline s regex, single-line regexp, single-line regular expression, single-line i regex, case-insensitive regexp, case-insensitive regular expression, case-insensitive x p regex, preserve regexp, preserve g c"

Regular Expressions

[1], [2], [3], [1], [2], [3], "$", "+" "<" "=" ">" "|" "~", "^" "`", cntrl , graph , print , punct , xdigit

Extended Patterns

"(?#text)" , "(?pimsx−imsx)" , "(?:pattern)" , "(?imsx−imsx:pattern)", "(?|pattern)" , Look-Around Assertions , "(?=pattern)" , "(?!pattern)" , "(?<=pattern)" "\K" , "(?<!pattern)" , "(?'NAME'pattern)", "(?<NAME>pattern)" , "\k<NAME>", "\k'NAME'", "(?{ code })" , "(??{ code })" , "(?PARNO)" "(?−PARNO)" "(?+PARNO)" "(?R)" "(?0)"

, "(?&NAME)" , "(?(condition)yes−pattern|no−pattern)" , "(?(condition)yes−pattern)", (1) (2) .., (< NAME >) (’ NAME ’), (?{ CODE }), (R), (R1) (R2) .., (R&NAME), ( DEFINE ), "(?>pattern)" positive lookahead, positive (?!) look-ahead, negative lookahead, negative (?<=) look-behind, positive lookbehind, positive K (?<!) look-behind, negative lookbehind, negative (?<NAME>) (?’NAME’) named capture capture (?{}) regex, code in regexp, code in regular expression, code in (??{}) regex, postponed regexp, postponed regular expression, postponed (?PARNO) (?1) (?R) (?0) (?-1) (?+1) (?-PARNO) (?+PARNO) regex, recursive regexp, recursive regular expression, recursive regex, relative recursion (?&NAME) (?() backtrack backtracking atomic possessive"

Special Backtracking Control Verbs

Verbs that take an argument, "(*PRUNE)" "(*PRUNE:NAME)" , "(*SKIP)" "(*SKIP:NAME)" , "(*MARK:NAME)" "(*:NAME)" "(*MARK:NAME)" "(*:NAME)", "(*THEN)" "(*THEN:NAME)", "(*COMMIT)" , Verbs without an argument, "(*FAIL)" "(*F)" , "(*ACCEPT)"

Backtracking

Version 8 Regular Expressions

Warning on \1 Instead of $1

Repeated Patterns Matching a Zero-length Substring

Combining RE Pieces

"ST", "S|T", "S{REPEAT_COUNT}", "S{min,max}", "S{min,max}?", "S?", "S*", "S+", "S??", "S*?", "S+?", "(?>S)", "(?=S)", "(?<=S)", "(?!S)", "(?<!S)", "(??{ EXPR })", "(?PARNO)", "(?(condition)yes−pattern|no−pattern)"

Creating Custom RE Engines

PCRE/Python Support

"(?PE<lt>NAMEE<gt>pattern)", "(?P=NAME)", "(?P>NAME)"

BUGS

SEE ALSO

perlrebackslash − Perl Regular Expression Backslash Sequences and Escapes

DESCRIPTION

The backslash

[1]

All the sequences and escapes

Character Escapes

[1], [2]

Modifiers

Character classes

Referencing

Assertions

\A, \z, \Z, \G, \b, \B

Misc

\C, \K, \R, \X

perlrecharclass − Perl Regular Expression Character Classes

DESCRIPTION

The dot

Backslashed sequences

[1]

Bracketed Character Classes

cntrl, graph, print, punct

Locale, Unicode and UTF−8

perlreref − Perl Regular Expressions Reference

DESCRIPTION

OPERATORS

SYNTAX

ESCAPE SEQUENCES

CHARACTER CLASSES

ANCHORS

QUANTIFIERS

EXTENDED CONSTRUCTS

VARIABLES

FUNCTIONS

TERMINOLOGY

AUTHOR

SEE ALSO

THANKS

perlref − Perl references and nested data structures

NOTE

DESCRIPTION

Making References

1. , 2. , 3.

, 4. , 5. , 6. , 7. anonymous subroutine, reference reference, subroutine scope, lexical closure lexical lexical scope constructor new autovivification *foo{THING} *"

Using References

Symbolic references

Not-so-symbolic references

Pseudo-hashes: Using an array as a hash

Function Templates

WARNING

SEE ALSO

perlform − Perl formats

DESCRIPTION

Text Fields

Numeric Fields

The Field @* for Variable Width Multi-Line Text

The Field ^* for Variable Width One-line-at-a-time Text

Specifying Values

Using Fill Mode

Suppressing Lines Where All Fields Are Void

Repeating Format Lines

Top of Form Processing

Format Variables

NOTES

Footers

Accessing Formatting Internals

WARNINGS

perlobj − Perl objects

DESCRIPTION

An Object is Simply a Reference

A Class is Simply a Package

A Method is Simply a Subroutine

Method Invocation

Indirect Object Syntax

Default UNIVERSAL methods

isa( CLASS ) , DOES ( ROLE ) , can( METHOD ) , VERSION ( [ NEED ] )

Destructors

Summary

Two-Phased Garbage Collection

SEE ALSO

perltie − how to hide an object class in a simple variable

SYNOPSIS

DESCRIPTION

Tying Scalars

TIESCALAR classname, LIST , FETCH this , STORE this, value , UNTIE this , DESTROY this

Tying Arrays

TIEARRAY classname, LIST , FETCH this, index , STORE this, index, value , FETCHSIZE this , STORESIZE this, count , EXTEND this, count , EXISTS this, key , DELETE this, key , CLEAR this , PUSH this, LIST , POP this , SHIFT this , UNSHIFT this, LIST , SPLICE this, offset, length, LIST , UNTIE this , DESTROY this

Tying Hashes

USER , HOME , CLOBBER , LIST , TIEHASH classname, LIST , FETCH this, key , STORE this, key, value , DELETE this, key , CLEAR this , EXISTS this, key , FIRSTKEY this , NEXTKEY this, lastkey , SCALAR this , UNTIE this , DESTROY this

Tying FileHandles

TIEHANDLE classname, LIST , WRITE this, LIST , PRINT this, LIST , PRINTF this, LIST , READ this, LIST , READLINE this , GETC this , CLOSE this , UNTIE this , DESTROY this

UNTIE this

The "untie" Gotcha

SEE ALSO

BUGS

AUTHOR

perldbmfilter − Perl DBM Filters

SYNOPSIS

DESCRIPTION

filter_store_key, filter_store_value, filter_fetch_key, filter_fetch_value

The Filter

An Example -- the NULL termination problem.

Another Example -- Key is a C int.

SEE ALSO

AUTHOR

perlipc − Perl interprocess communication (signals, fifos, pipes, safe subprocesses, sockets, and semaphores)

DESCRIPTION

Signals

Handling the SIGHUP Signal in Daemons

Named Pipes

Deferred Signals (Safe Signals)

Long-running opcodes, Interrupting IO , Restartable system calls, Signals as "faults", Signals triggered by operating system state

Using open() for IPC

Filehandles

Background Processes

Complete Dissociation of Child from Parent

Safe Pipe Opens

Avoiding Pipe Deadlocks

Bidirectional Communication with Another Process

Bidirectional Communication with Yourself

Sockets: Client/Server Communication

Internet Line Terminators

Internet TCP Clients and Servers

Unix-Domain TCP Clients and Servers

TCP Clients with IO::Socket

A Simple Client

"Proto", "PeerAddr", "PeerPort"

A Webget Client

Interactive Client with IO::Socket

TCP Servers with IO::Socket

Proto, LocalPort, Listen, Reuse

UDP: Message Passing

SysV IPC

NOTES

BUGS

AUTHOR

SEE ALSO

perlfork − Perl’s fork() emulation

SYNOPSIS

DESCRIPTION

Behavior of other Perl features in forked pseudo-processes

$$ or $PROCESS_ID, %ENV, chdir() and all other builtins that accept filenames, wait() and waitpid(), kill(), exec(), exit(), Open handles to files, directories and network sockets

Resource limits

Killing the parent process

Lifetime of the parent process and pseudo-processes

CAVEATS AND LIMITATIONS

BEGIN blocks, Open filehandles, Forking pipe open() not yet implemented, Global state maintained by XSUBs, Interpreter embedded in larger application, Thread-safety of extensions

BUGS

AUTHOR

SEE ALSO

perlnumber − semantics of numbers and numeric operations in Perl

SYNOPSIS

DESCRIPTION

Storing numbers

Numeric operators and numeric conversions

Flavors of Perl numeric operations

Arithmetic operators, ++, Arithmetic operators during "use integer", Other mathematical operators, Bitwise operators, Bitwise operators during "use integer", Operators which expect an integer, Operators which expect a string

AUTHOR

SEE ALSO

perlthrtut − Tutorial on threads in Perl

DESCRIPTION

What Is A Thread Anyway?

Threaded Program Models

Boss/Worker

Work Crew