NAME

perlmodlib - constructing new Perl modules and finding existing ones

THE PERL MODULE LIBRARY

Many modules are included in the Perl distribution. These are described below, and all end in .pm. You may discover compiled library files (usually ending in .so) or small pieces of modules to be autoloaded (ending in .al); these were automatically generated by the installation process. You may also discover files in the library directory that end in either .pl or .ph. These are old libraries supplied so that old programs that use them still run. The .pl files will all eventually be converted into standard modules, and the .ph files made by h2ph will probably end up as extension modules made by h2xs. (Some .ph values may already be available through the POSIX, Errno, or Fcntl modules.) The pl2pm file in the distribution may help in your conversion, but it's just a mechanical process and therefore far from bulletproof.

Pragmatic Modules

They work somewhat like compiler directives (pragmata) in that they tend to affect the compilation of your program, and thus will usually work well only when used within a "use", or "no". Most of these are lexically scoped, so an inner BLOCK may countermand them by saying:
    no integer;
    no strict 'refs';
    no warnings;
which lasts until the end of that BLOCK.
Some pragmas are lexically scoped--typically those that affect the $^H hints variable. Others affect the current package instead, like "use vars" and "use subs", which allow you to predeclare a variables or subroutines within a particular file rather than just a block. Such declarations are effective for the entire file for which they were declared. You cannot rescind them with "no vars" or "no subs".
The following pragmas are defined (and have their own documentation).
attributes
Get/set subroutine or variable attributes
autodie
Replace functions with ones that succeed or die with lexical scope
autodie::exception
Exceptions from autodying functions.
autodie::exception::system
Exceptions from autodying system().
autodie::hints
Provide hints about user subroutines to autodie
autodie::skip
Skip a package when throwing autodie exceptions
autouse
Postpone load of modules until a function is used
base
Establish an ISA relationship with base classes at compile time
bigfloat
Transparent big floating point number support for Perl
bigint
Transparent big integer support for Perl
bignum
Transparent big number support for Perl
bigrat
Transparent big rational number support for Perl
blib
Use MakeMaker's uninstalled version of a package
builtin
Import built-in utility functions
bytes
Expose the individual bytes of characters
charnames
Access to Unicode character names and named character sequences; also define character names
constant
Declare constants
deprecate
Perl pragma for deprecating the inclusion of a module in core
diagnostics
Produce verbose warning diagnostics
encoding
Allows you to write your script in non-ASCII and non-UTF-8
encoding::warnings
Warn on implicit encoding conversions
experimental
Experimental features made easy
feature
Enable new features
fields
Compile-time class fields
filetest
Control the filetest permission operators
if
"use" a Perl module if a condition holds
integer
Use integer arithmetic instead of floating point
less
Request less of something
lib
Manipulate @INC at compile time
locale
Use or avoid POSIX locales for built-in operations
mro
Method Resolution Order
ok
Alternative to Test::More::use_ok
open
Set default PerlIO layers for input and output
ops
Restrict unsafe operations when compiling
overload
Package for overloading Perl operations
overloading
Lexically control overloading
parent
Establish an ISA relationship with base classes at compile time
re
Alter regular expression behaviour
sigtrap
Enable simple signal handling
sort
Control sort() behaviour
strict
Restrict unsafe constructs
subs
Predeclare subroutine names
threads
Perl interpreter-based threads
threads::shared
Perl extension for sharing data structures between threads
utf8
Enable/disable UTF-8 (or UTF-EBCDIC) in source code
vars
Predeclare global variable names
version
Perl extension for Version Objects
vmsish
Control VMS-specific language features
warnings
Control optional warnings
warnings::register
Warnings import function

Standard Modules

Standard, bundled modules are all expected to behave in a well-defined manner with respect to namespace pollution because they use the Exporter module. See their own documentation for details.
It's possible that not all modules listed below are installed on your system. For example, the GDBM_File module will not be installed if you don't have the gdbm library.
Amiga::ARexx
Perl extension for ARexx support
Amiga::Exec
Perl extension for low level amiga support
AnyDBM_File
Provide framework for multiple DBMs
App::Cpan
Easily interact with CPAN from the command line
App::Prove
Implements the "prove" command.
App::Prove::State
State storage for the "prove" command.
App::Prove::State::Result
Individual test suite results.
App::Prove::State::Result::Test
Individual test results.
Archive::Tar
Module for manipulations of tar archives
Archive::Tar::File
A subclass for in-memory extracted file from Archive::Tar
Attribute::Handlers
Simpler definition of attribute handlers
AutoLoader
Load subroutines only on demand
AutoSplit
Split a package for autoloading
B
The Perl Compiler Backend
B::Concise
Walk Perl syntax tree, printing concise info about ops
B::Deparse
Perl compiler backend to produce perl code
B::Op_private
OP op_private flag definitions
B::Showlex
Show lexical variables used in functions or files
B::Terse
Walk Perl syntax tree, printing terse info about ops
B::Xref
Generates cross reference reports for Perl programs
Benchmark
Benchmark running times of Perl code
"IO::Socket::IP"
Family-neutral IP socket supporting both IPv4 and IPv6
"Socket"
Networking constants and support functions
CORE
Namespace for Perl's core routines
CPAN
Query, download and build perl modules from CPAN sites
CPAN::API::HOWTO
A recipe book for programming with CPAN.pm
CPAN::Debug
Internal debugging for CPAN.pm
CPAN::Distroprefs
Read and match distroprefs
CPAN::FirstTime
Utility for CPAN::Config file Initialization
CPAN::HandleConfig
Internal configuration handling for CPAN.pm
CPAN::Kwalify
Interface between CPAN.pm and Kwalify.pm
CPAN::Meta
The distribution metadata for a CPAN dist
CPAN::Meta::Converter
Convert CPAN distribution metadata structures
CPAN::Meta::Feature
An optional feature provided by a CPAN distribution
CPAN::Meta::History
History of CPAN Meta Spec changes
CPAN::Meta::History::Meta_1_0
Version 1.0 metadata specification for META.yml
CPAN::Meta::History::Meta_1_1
Version 1.1 metadata specification for META.yml
CPAN::Meta::History::Meta_1_2
Version 1.2 metadata specification for META.yml
CPAN::Meta::History::Meta_1_3
Version 1.3 metadata specification for META.yml
CPAN::Meta::History::Meta_1_4
Version 1.4 metadata specification for META.yml
CPAN::Meta::Merge
Merging CPAN Meta fragments
CPAN::Meta::Prereqs
A set of distribution prerequisites by phase and type
CPAN::Meta::Requirements
A set of version requirements for a CPAN dist
CPAN::Meta::Spec
Specification for CPAN distribution metadata
CPAN::Meta::Validator
Validate CPAN distribution metadata structures
CPAN::Meta::YAML
Read and write a subset of YAML for CPAN Meta files
CPAN::Nox
Wrapper around CPAN.pm without using any XS module
CPAN::Plugin
Base class for CPAN shell extensions
CPAN::Plugin::Specfile
Proof of concept implementation of a trivial CPAN::Plugin
CPAN::Queue
Internal queue support for CPAN.pm
CPAN::Tarzip
Internal handling of tar archives for CPAN.pm
CPAN::Version
Utility functions to compare CPAN versions
Carp
Alternative warn and die for modules
Class::Struct
Declare struct-like datatypes as Perl classes
Compress::Raw::Bzip2
Low-Level Interface to bzip2 compression library
Compress::Raw::Zlib
Low-Level Interface to zlib compression library
Compress::Zlib
Interface to zlib compression library
Config
Access Perl configuration information
Config::Extensions
Hash lookup of which core extensions were built.
Config::Perl::V
Structured data retrieval of perl -V output
Cwd
Get pathname of current working directory
DB
Programmatic interface to the Perl debugging API
DBM_Filter
Filter DBM keys/values
DBM_Filter::compress
Filter for DBM_Filter
DBM_Filter::encode
Filter for DBM_Filter
DBM_Filter::int32
Filter for DBM_Filter
DBM_Filter::null
Filter for DBM_Filter
DBM_Filter::utf8
Filter for DBM_Filter
DB_File
Perl5 access to Berkeley DB version 1.x
Data::Dumper
Stringified perl data structures, suitable for both printing and "eval"
Devel::PPPort
Perl/Pollution/Portability
Devel::Peek
A data debugging tool for the XS programmer
Devel::SelfStubber
Generate stubs for a SelfLoading module
Digest
Modules that calculate message digests
Digest::MD5
Perl interface to the MD5 Algorithm
Digest::SHA
Perl extension for SHA-1/224/256/384/512
Digest::base
Digest base class
Digest::file
Calculate digests of files
DirHandle
(obsolete) supply object methods for directory handles
Dumpvalue
Provides screen dump of Perl data.
DynaLoader
Dynamically load C libraries into Perl code
Encode
Character encodings in Perl
Encode::Alias
Alias definitions to encodings
Encode::Byte
Single Byte Encodings
Encode::CJKConstants
Internally used by Encode::??::ISO_2022_*
Encode::CN
China-based Chinese Encodings
Encode::CN::HZ
Internally used by Encode::CN
Encode::Config
Internally used by Encode
Encode::EBCDIC
EBCDIC Encodings
Encode::Encoder
Object Oriented Encoder
Encode::Encoding
Encode Implementation Base Class
Encode::GSM0338
ETSI GSM 03.38 Encoding
Encode::Guess
Guesses encoding from data
Encode::JP
Japanese Encodings
Encode::JP::H2Z
Internally used by Encode::JP::2022_JP*
Encode::JP::JIS7
Internally used by Encode::JP
Encode::KR
Korean Encodings
Encode::KR::2022_KR
Internally used by Encode::KR
Encode::MIME::Header
MIME encoding for an unstructured email header
Encode::MIME::Name
Internally used by Encode
Encode::PerlIO
A detailed document on Encode and PerlIO
Encode::Supported
Encodings supported by Encode
Encode::Symbol
Symbol Encodings
Encode::TW
Taiwan-based Chinese Encodings
Encode::Unicode
Various Unicode Transformation Formats
Encode::Unicode::UTF7
UTF-7 encoding
English
Use nice English (or awk) names for ugly punctuation variables
Env
Perl module that imports environment variables as scalars or arrays
Errno
System errno constants
Exporter
Implements default import method for modules
Exporter::Heavy
Exporter guts
ExtUtils::CBuilder
Compile and link C code for Perl modules
ExtUtils::CBuilder::Platform::Windows
Builder class for Windows platforms
ExtUtils::Command
Utilities to replace common UNIX commands in Makefiles etc.
ExtUtils::Command::MM
Commands for the MM's to use in Makefiles
ExtUtils::Constant
Generate XS code to import C header constants
ExtUtils::Constant::Base
Base class for ExtUtils::Constant objects
ExtUtils::Constant::Utils
Helper functions for ExtUtils::Constant
ExtUtils::Constant::XS
Generate C code for XS modules' constants.
ExtUtils::Embed
Utilities for embedding Perl in C/C++ applications
ExtUtils::Install
Install files from here to there
ExtUtils::Installed
Inventory management of installed modules
ExtUtils::Liblist
Determine libraries to use and how to use them
ExtUtils::MM
OS adjusted ExtUtils::MakeMaker subclass
ExtUtils::MM_AIX
AIX specific subclass of ExtUtils::MM_Unix
ExtUtils::MM_Any
Platform-agnostic MM methods
ExtUtils::MM_BeOS
Methods to override UN*X behaviour in ExtUtils::MakeMaker
ExtUtils::MM_Cygwin
Methods to override UN*X behaviour in ExtUtils::MakeMaker
ExtUtils::MM_DOS
DOS specific subclass of ExtUtils::MM_Unix
ExtUtils::MM_Darwin
Special behaviors for OS X
ExtUtils::MM_MacOS
Once produced Makefiles for MacOS Classic
ExtUtils::MM_NW5
Methods to override UN*X behaviour in ExtUtils::MakeMaker
ExtUtils::MM_OS2
Methods to override UN*X behaviour in ExtUtils::MakeMaker
ExtUtils::MM_OS390
OS390 specific subclass of ExtUtils::MM_Unix
ExtUtils::MM_QNX
QNX specific subclass of ExtUtils::MM_Unix
ExtUtils::MM_UWIN
U/WIN specific subclass of ExtUtils::MM_Unix
ExtUtils::MM_Unix
Methods used by ExtUtils::MakeMaker
ExtUtils::MM_VMS
Methods to override UN*X behaviour in ExtUtils::MakeMaker
ExtUtils::MM_VOS
VOS specific subclass of ExtUtils::MM_Unix
ExtUtils::MM_Win32
Methods to override UN*X behaviour in ExtUtils::MakeMaker
ExtUtils::MM_Win95
Method to customize MakeMaker for Win9X
ExtUtils::MY
ExtUtils::MakeMaker subclass for customization
ExtUtils::MakeMaker
Create a module Makefile
ExtUtils::MakeMaker::Config
Wrapper around Config.pm
ExtUtils::MakeMaker::FAQ
Frequently Asked Questions About MakeMaker
ExtUtils::MakeMaker::Locale
Bundled Encode::Locale
ExtUtils::MakeMaker::Tutorial
Writing a module with MakeMaker
ExtUtils::Manifest
Utilities to write and check a MANIFEST file
ExtUtils::Miniperl
Write the C code for miniperlmain.c and perlmain.c
ExtUtils::Mkbootstrap
Make a bootstrap file for use by DynaLoader
ExtUtils::Mksymlists
Write linker options files for dynamic extension
ExtUtils::PL2Bat
Batch file creation to run perl scripts on Windows
ExtUtils::Packlist
Manage .packlist files
ExtUtils::ParseXS
Converts Perl XS code into C code
ExtUtils::ParseXS::Constants
Initialization values for some globals
ExtUtils::ParseXS::Eval
Clean package to evaluate code in
ExtUtils::ParseXS::Utilities
Subroutines used with ExtUtils::ParseXS
ExtUtils::Typemaps
Read/Write/Modify Perl/XS typemap files
ExtUtils::Typemaps::Cmd
Quick commands for handling typemaps
ExtUtils::Typemaps::InputMap
Entry in the INPUT section of a typemap
ExtUtils::Typemaps::OutputMap
Entry in the OUTPUT section of a typemap
ExtUtils::Typemaps::Type
Entry in the TYPEMAP section of a typemap
ExtUtils::XSSymSet
Keep sets of symbol names palatable to the VMS linker
ExtUtils::testlib
Add blib/* directories to @INC
Fatal
Replace functions with equivalents which succeed or die
Fcntl
Load the C Fcntl.h defines
File::Basename
Parse file paths into directory, filename and suffix.
File::Compare
Compare files or filehandles
File::Copy
Copy files or filehandles
File::DosGlob
DOS like globbing and then some
File::Fetch
A generic file fetching mechanism
File::Find
Traverse a directory tree.
File::Glob
Perl extension for BSD glob routine
File::GlobMapper
Extend File Glob to Allow Input and Output Files
File::Path
Create or remove directory trees
File::Spec
Portably perform operations on file names
File::Spec::AmigaOS
File::Spec for AmigaOS
File::Spec::Cygwin
Methods for Cygwin file specs
File::Spec::Epoc
Methods for Epoc file specs
File::Spec::Functions
Portably perform operations on file names
File::Spec::Mac
File::Spec for Mac OS (Classic)
File::Spec::OS2
Methods for OS/2 file specs
File::Spec::Unix
File::Spec for Unix, base for other File::Spec modules
File::Spec::VMS
Methods for VMS file specs
File::Spec::Win32
Methods for Win32 file specs
File::Temp
Return name and handle of a temporary file safely
File::stat
By-name interface to Perl's built-in stat() functions
FileCache
Keep more files open than the system permits
FileHandle
Supply object methods for filehandles
Filter::Simple
Simplified source filtering
Filter::Util::Call
Perl Source Filter Utility Module
FindBin
Locate directory of original perl script
GDBM_File
Perl5 access to the gdbm library.
Getopt::Long
Extended processing of command line options
Getopt::Std
Process single-character switches with switch clustering
HTTP::Tiny
A small, simple, correct HTTP/1.1 client
Hash::Util
A selection of general-utility hash subroutines
Hash::Util::FieldHash
Support for Inside-Out Classes
I18N::Collate
Compare 8-bit scalar data according to the current locale
I18N::LangTags
Functions for dealing with RFC3066-style language tags
I18N::LangTags::Detect
Detect the user's language preferences
I18N::LangTags::List
Tags and names for human languages
I18N::Langinfo
Query locale information
IO
Load various IO modules
IO::Compress::Base
Base Class for IO::Compress modules
IO::Compress::Bzip2
Write bzip2 files/buffers
IO::Compress::Deflate
Write RFC 1950 files/buffers
IO::Compress::FAQ
Frequently Asked Questions about IO::Compress
IO::Compress::Gzip
Write RFC 1952 files/buffers
IO::Compress::RawDeflate
Write RFC 1951 files/buffers
IO::Compress::Zip
Write zip files/buffers
IO::Dir
Supply object methods for directory handles
IO::File
Supply object methods for filehandles
IO::Handle
Supply object methods for I/O handles
IO::Pipe
Supply object methods for pipes
IO::Poll
Object interface to system poll call
IO::Seekable
Supply seek based methods for I/O objects
IO::Select
OO interface to the select system call
IO::Socket
Object interface to socket communications
IO::Socket::INET
Object interface for AF_INET domain sockets
IO::Socket::UNIX
Object interface for AF_UNIX domain sockets
IO::Uncompress::AnyInflate
Uncompress zlib-based (zip, gzip) file/buffer
IO::Uncompress::AnyUncompress
Uncompress gzip, zip, bzip2, zstd, xz, lzma, lzip, lzf or lzop file/buffer
IO::Uncompress::Base
Base Class for IO::Uncompress modules
IO::Uncompress::Bunzip2
Read bzip2 files/buffers
IO::Uncompress::Gunzip
Read RFC 1952 files/buffers
IO::Uncompress::Inflate
Read RFC 1950 files/buffers
IO::Uncompress::RawInflate
Read RFC 1951 files/buffers
IO::Uncompress::Unzip
Read zip files/buffers
IO::Zlib
IO:: style interface to Compress::Zlib
IPC::Cmd
Finding and running system commands made easy
IPC::Msg
SysV Msg IPC object class
IPC::Open2
Open a process for both reading and writing using open2()
IPC::Open3
Open a process for reading, writing, and error handling using open3()
IPC::Semaphore
SysV Semaphore IPC object class
IPC::SharedMem
SysV Shared Memory IPC object class
IPC::SysV
System V IPC constants and system calls
Internals
Reserved special namespace for internals related functions
JSON::PP
JSON::XS compatible pure-Perl module.
JSON::PP::Boolean
Dummy module providing JSON::PP::Boolean
List::Util
A selection of general-utility list subroutines
List::Util::XS
Indicate if List::Util was compiled with a C compiler
Locale::Maketext
Framework for localization
Locale::Maketext::Cookbook
Recipes for using Locale::Maketext
Locale::Maketext::Guts
Deprecated module to load Locale::Maketext utf8 code
Locale::Maketext::GutsLoader
Deprecated module to load Locale::Maketext utf8 code
Locale::Maketext::Simple
Simple interface to Locale::Maketext::Lexicon
Locale::Maketext::TPJ13
Article about software localization
MIME::Base64
Encoding and decoding of base64 strings
MIME::QuotedPrint
Encoding and decoding of quoted-printable strings
Math::BigFloat
Arbitrary size floating point math package
Math::BigInt
Arbitrary size integer math package
Math::BigInt::Calc
Pure Perl module to support Math::BigInt
Math::BigInt::FastCalc
Math::BigInt::Calc with some XS for more speed
Math::BigInt::Lib
Virtual parent class for Math::BigInt libraries
Math::BigRat
Arbitrary size rational number math package
Math::Complex
Complex numbers and associated mathematical functions
Math::Trig
Trigonometric functions
Memoize
Make functions faster by trading space for time
Memoize::AnyDBM_File
Glue to provide EXISTS for AnyDBM_File for Storable use
Memoize::Expire
Plug-in module for automatic expiration of memoized values
Memoize::ExpireFile
Test for Memoize expiration semantics
Memoize::ExpireTest
Test for Memoize expiration semantics
Memoize::NDBM_File
Glue to provide EXISTS for NDBM_File for Storable use
Memoize::SDBM_File
Glue to provide EXISTS for SDBM_File for Storable use
Memoize::Storable
Store Memoized data in Storable database
Module::CoreList
What modules shipped with versions of perl
Module::CoreList::Utils
What utilities shipped with versions of perl
Module::Load
Runtime require of both modules and files
Module::Load::Conditional
Looking up module information / loading at runtime
Module::Loaded
Mark modules as loaded or unloaded
Module::Metadata
Gather package and POD information from perl module files
NDBM_File
Tied access to ndbm files
NEXT
Provide a pseudo-class NEXT (et al) that allows method redispatch
Net::Cmd
Network Command class (as used by FTP, SMTP etc)
Net::Config
Local configuration data for libnet
Net::Domain
Attempt to evaluate the current host's internet name and domain
Net::FTP
FTP Client class
Net::FTP::dataconn
FTP Client data connection class
Net::NNTP
NNTP Client class
Net::Netrc
OO interface to users netrc file
Net::POP3
Post Office Protocol 3 Client class (RFC1939)
Net::Ping
Check a remote host for reachability
Net::SMTP
Simple Mail Transfer Protocol Client
Net::Time
Time and daytime network client interface
Net::hostent
By-name interface to Perl's built-in gethost*() functions
Net::libnetFAQ
Libnet Frequently Asked Questions
Net::netent
By-name interface to Perl's built-in getnet*() functions
Net::protoent
By-name interface to Perl's built-in getproto*() functions
Net::servent
By-name interface to Perl's built-in getserv*() functions
O
Generic interface to Perl Compiler backends
ODBM_File
Tied access to odbm files
Opcode
Disable named opcodes when compiling perl code
POSIX
Perl interface to IEEE Std 1003.1
Params::Check
A generic input parsing/checking mechanism.
Parse::CPAN::Meta
Parse META.yml and META.json CPAN metadata files
Perl::OSType
Map Perl operating system names to generic types
PerlIO
On demand loader for PerlIO layers and root of PerlIO::* name space
PerlIO::encoding
Encoding layer
PerlIO::mmap
Memory mapped IO
PerlIO::scalar
In-memory IO, scalar IO
PerlIO::via
Helper class for PerlIO layers implemented in perl
PerlIO::via::QuotedPrint
PerlIO layer for quoted-printable strings
Pod::Checker
Check pod documents for syntax errors
Pod::Escapes
For resolving Pod E<...> sequences
Pod::Functions
Group Perl's functions a la perlfunc.pod
Pod::Html
Module to convert pod files to HTML
Pod::Html::Util
Helper functions for Pod-Html
Pod::Man
Convert POD data to formatted *roff input
Pod::ParseLink
Parse an L<> formatting code in POD text
Pod::Perldoc
Look up Perl documentation in Pod format.
Pod::Perldoc::BaseTo
Base for Pod::Perldoc formatters
Pod::Perldoc::GetOptsOO
Customized option parser for Pod::Perldoc
Pod::Perldoc::ToANSI
Render Pod with ANSI color escapes
Pod::Perldoc::ToChecker
Let Perldoc check Pod for errors
Pod::Perldoc::ToMan
Let Perldoc render Pod as man pages
Pod::Perldoc::ToNroff
Let Perldoc convert Pod to nroff
Pod::Perldoc::ToPod
Let Perldoc render Pod as ... Pod!
Pod::Perldoc::ToRtf
Let Perldoc render Pod as RTF
Pod::Perldoc::ToTerm
Render Pod with terminal escapes
Pod::Perldoc::ToText
Let Perldoc render Pod as plaintext
Pod::Perldoc::ToTk
Let Perldoc use Tk::Pod to render Pod
Pod::Perldoc::ToXml
Let Perldoc render Pod as XML
Pod::Simple
Framework for parsing Pod
Pod::Simple::Checker
Check the Pod syntax of a document
Pod::Simple::Debug
Put Pod::Simple into trace/debug mode
Pod::Simple::DumpAsText
Dump Pod-parsing events as text
Pod::Simple::DumpAsXML
Turn Pod into XML
Pod::Simple::HTML
Convert Pod to HTML
Pod::Simple::HTMLBatch
Convert several Pod files to several HTML files
Pod::Simple::JustPod
Just the Pod, the whole Pod, and nothing but the Pod
Pod::Simple::LinkSection
Represent "section" attributes of L codes
Pod::Simple::Methody
Turn Pod::Simple events into method calls
Pod::Simple::PullParser
A pull-parser interface to parsing Pod
Pod::Simple::PullParserEndToken
End-tokens from Pod::Simple::PullParser
Pod::Simple::PullParserStartToken
Start-tokens from Pod::Simple::PullParser
Pod::Simple::PullParserTextToken
Text-tokens from Pod::Simple::PullParser
Pod::Simple::PullParserToken
Tokens from Pod::Simple::PullParser
Pod::Simple::RTF
Format Pod as RTF
Pod::Simple::Search
Find POD documents in directory trees
Pod::Simple::SimpleTree
Parse Pod into a simple parse tree
Pod::Simple::Subclassing
Write a formatter as a Pod::Simple subclass
Pod::Simple::Text
Format Pod as plaintext
Pod::Simple::TextContent
Get the text content of Pod
Pod::Simple::XHTML
Format Pod as validating XHTML
Pod::Simple::XMLOutStream
Turn Pod into XML
Pod::Text
Convert POD data to formatted text
Pod::Text::Color
Convert POD data to formatted color ASCII text
Pod::Text::Overstrike
Convert POD data to formatted overstrike text
Pod::Text::Termcap
Convert POD data to ASCII text with format escapes
Pod::Usage
Extracts POD documentation and shows usage information
SDBM_File
Tied access to sdbm files
Safe
Compile and execute code in restricted compartments
Scalar::Util
A selection of general-utility scalar subroutines
Search::Dict
Look - search for key in dictionary file
SelectSaver
Save and restore selected file handle
SelfLoader
Load functions only on demand
Storable
Persistence for Perl data structures
Sub::Util
A selection of utility subroutines for subs and CODE references
Symbol
Manipulate Perl symbols and their names
Sys::Hostname
Try every conceivable way to get hostname
Sys::Syslog
Perl interface to the UNIX syslog(3) calls
Sys::Syslog::Win32
Win32 support for Sys::Syslog
TAP::Base
Base class that provides common functionality to TAP::Parser
TAP::Formatter::Base
Base class for harness output delegates
TAP::Formatter::Color
Run Perl test scripts with color
TAP::Formatter::Console
Harness output delegate for default console output
TAP::Formatter::Console::ParallelSession
Harness output delegate for parallel console output
TAP::Formatter::Console::Session
Harness output delegate for default console output
TAP::Formatter::File
Harness output delegate for file output
TAP::Formatter::File::Session
Harness output delegate for file output
TAP::Formatter::Session
Abstract base class for harness output delegate
TAP::Harness
Run test scripts with statistics
TAP::Harness::Env
Parsing harness related environmental variables where appropriate
TAP::Object
Base class that provides common functionality to all "TAP::*" modules
TAP::Parser
Parse TAP output
TAP::Parser::Aggregator
Aggregate TAP::Parser results
TAP::Parser::Grammar
A grammar for the Test Anything Protocol.
TAP::Parser::Iterator
Base class for TAP source iterators
TAP::Parser::Iterator::Array
Iterator for array-based TAP sources
TAP::Parser::Iterator::Process
Iterator for process-based TAP sources
TAP::Parser::Iterator::Stream
Iterator for filehandle-based TAP sources
TAP::Parser::IteratorFactory
Figures out which SourceHandler objects to use for a given Source
TAP::Parser::Multiplexer
Multiplex multiple TAP::Parsers
TAP::Parser::Result
Base class for TAP::Parser output objects
TAP::Parser::Result::Bailout
Bailout result token.
TAP::Parser::Result::Comment
Comment result token.
TAP::Parser::Result::Plan
Plan result token.
TAP::Parser::Result::Pragma
TAP pragma token.
TAP::Parser::Result::Test
Test result token.
TAP::Parser::Result::Unknown
Unknown result token.
TAP::Parser::Result::Version
TAP syntax version token.
TAP::Parser::Result::YAML
YAML result token.
TAP::Parser::ResultFactory
Factory for creating TAP::Parser output objects
TAP::Parser::Scheduler
Schedule tests during parallel testing
TAP::Parser::Scheduler::Job
A single testing job.
TAP::Parser::Scheduler::Spinner
A no-op job.
TAP::Parser::Source
A TAP source & meta data about it
TAP::Parser::SourceHandler
Base class for different TAP source handlers
TAP::Parser::SourceHandler::Executable
Stream output from an executable TAP source
TAP::Parser::SourceHandler::File
Stream TAP from a text file.
TAP::Parser::SourceHandler::Handle
Stream TAP from an IO::Handle or a GLOB.
TAP::Parser::SourceHandler::Perl
Stream TAP from a Perl executable
TAP::Parser::SourceHandler::RawTAP
Stream output from raw TAP in a scalar/array ref.
TAP::Parser::YAMLish::Reader
Read YAMLish data from iterator
TAP::Parser::YAMLish::Writer
Write YAMLish data
Term::ANSIColor
Color screen output using ANSI escape sequences
Term::Cap
Perl termcap interface
Term::Complete
Perl word completion module
Term::ReadLine
Perl interface to various "readline" packages.
Test
Provides a simple framework for writing test scripts
Test2
Framework for writing test tools that all work together.
Test2::API
Primary interface for writing Test2 based testing tools.
Test2::API::Breakage
What breaks at what version
Test2::API::Context
Object to represent a testing context.
Test2::API::Instance
Object used by Test2::API under the hood
Test2::API::InterceptResult
Representation of a list of events.
Test2::API::InterceptResult::Event
Representation of an event for use in
Test2::API::InterceptResult::Hub
Hub used by InterceptResult.
Test2::API::InterceptResult::Squasher
Encapsulation of the algorithm that
Test2::API::Stack
Object to manage a stack of Test2::Hub
Test2::Event
Base class for events
Test2::Event::Bail
Bailout!
Test2::Event::Diag
Diag event type
Test2::Event::Encoding
Set the encoding for the output stream
Test2::Event::Exception
Exception event
Test2::Event::Fail
Event for a simple failed assertion
Test2::Event::Generic
Generic event type.
Test2::Event::Note
Note event type
Test2::Event::Ok
Ok event type
Test2::Event::Pass
Event for a simple passing assertion
Test2::Event::Plan
The event of a plan
Test2::Event::Skip
Skip event type
Test2::Event::Subtest
Event for subtest types
Test2::Event::TAP::Version
Event for TAP version.
Test2::Event::V2
Second generation event.
Test2::Event::Waiting
Tell all procs/threads it is time to be done
Test2::EventFacet
Base class for all event facets.
Test2::EventFacet::About
Facet with event details.
Test2::EventFacet::Amnesty
Facet for assertion amnesty.
Test2::EventFacet::Assert
Facet representing an assertion.
Test2::EventFacet::Control
Facet for hub actions and behaviors.
Test2::EventFacet::Error
Facet for errors that need to be shown.
Test2::EventFacet::Hub
Facet for the hubs an event passes through.
Test2::EventFacet::Info
Facet for information a developer might care about.
Test2::EventFacet::Info::Table
Intermediary representation of a table.
Test2::EventFacet::Meta
Facet for meta-data
Test2::EventFacet::Parent
Facet for events contains other events
Test2::EventFacet::Plan
Facet for setting the plan
Test2::EventFacet::Render
Facet that dictates how to render an event.
Test2::EventFacet::Trace
Debug information for events
Test2::Formatter
Namespace for formatters.
Test2::Formatter::TAP
Standard TAP formatter
Test2::Hub
The conduit through which all events flow.
Test2::Hub::Interceptor
Hub used by interceptor to grab results.
Test2::Hub::Interceptor::Terminator
Exception class used by
Test2::Hub::Subtest
Hub used by subtests
Test2::IPC
Turn on IPC for threading or forking support.
Test2::IPC::Driver
Base class for Test2 IPC drivers.
Test2::IPC::Driver::Files
Temp dir + Files concurrency model.
Test2::Tools::Tiny
Tiny set of tools for unfortunate souls who cannot use
Test2::Transition
Transition notes when upgrading to Test2
Test2::Util
Tools used by Test2 and friends.
Test2::Util::ExternalMeta
Allow third party tools to safely attach meta-data
Test2::Util::Facets2Legacy
Convert facet data to the legacy event API.
Test2::Util::HashBase
Build hash based classes.
Test2::Util::Trace
Legacy wrapper fro Test2::EventFacet::Trace.
Test::Builder
Backend for building test libraries
Test::Builder::Formatter
Test::Builder subclass of Test2::Formatter::TAP
Test::Builder::IO::Scalar
A copy of IO::Scalar for Test::Builder
Test::Builder::Module
Base class for test modules
Test::Builder::Tester
Test testsuites that have been built with
Test::Builder::Tester::Color
Turn on colour in Test::Builder::Tester
Test::Builder::TodoDiag
Test::Builder subclass of Test2::Event::Diag
Test::Harness
Run Perl standard test scripts with statistics
Test::Harness::Beyond
Beyond make test
Test::More
Yet another framework for writing test scripts
Test::Simple
Basic utilities for writing tests.
Test::Tester
Ease testing test modules built with Test::Builder
Test::Tester::Capture
Help testing test modules built with Test::Builder
Test::Tester::CaptureRunner
Help testing test modules built with Test::Builder
Test::Tutorial
A tutorial about writing really basic tests
Test::use::ok
Alternative to Test::More::use_ok
Text::Abbrev
Abbrev - create an abbreviation table from a list
Text::Balanced
Extract delimited text sequences from strings.
Text::ParseWords
Parse text into an array of tokens or array of arrays
Text::Tabs
Expand and unexpand tabs like unix expand(1) and unexpand(1)
Text::Wrap
Line wrapping to form simple paragraphs
Thread
Manipulate threads in Perl (for old code only)
Thread::Queue
Thread-safe queues
Thread::Semaphore
Thread-safe semaphores
Tie::Array
Base class for tied arrays
Tie::File
Access the lines of a disk file via a Perl array
Tie::Handle
Base class definitions for tied handles
Tie::Hash
Base class definitions for tied hashes
Tie::Hash::NamedCapture
Named regexp capture buffers
Tie::Memoize
Add data to hash when needed
Tie::RefHash
Use references as hash keys
Tie::Scalar
Base class definitions for tied scalars
Tie::StdHandle
Base class definitions for tied handles
Tie::SubstrHash
Fixed-table-size, fixed-key-length hashing
Time::HiRes
High resolution alarm, sleep, gettimeofday, interval timers
Time::Local
Efficiently compute time from local and GMT time
Time::Piece
Object Oriented time objects
Time::Seconds
A simple API to convert seconds to other date values
Time::gmtime
By-name interface to Perl's built-in gmtime() function
Time::localtime
By-name interface to Perl's built-in localtime() function
Time::tm
Internal object used by Time::gmtime and Time::localtime
UNIVERSAL
Base class for ALL classes (blessed references)
Unicode::Collate
Unicode Collation Algorithm
Unicode::Collate::CJK::Big5
Weighting CJK Unified Ideographs
Unicode::Collate::CJK::GB2312
Weighting CJK Unified Ideographs
Unicode::Collate::CJK::JISX0208
Weighting JIS KANJI for Unicode::Collate
Unicode::Collate::CJK::Korean
Weighting CJK Unified Ideographs
Unicode::Collate::CJK::Pinyin
Weighting CJK Unified Ideographs
Unicode::Collate::CJK::Stroke
Weighting CJK Unified Ideographs
Unicode::Collate::CJK::Zhuyin
Weighting CJK Unified Ideographs
Unicode::Collate::Locale
Linguistic tailoring for DUCET via Unicode::Collate
Unicode::Normalize
Unicode Normalization Forms
Unicode::UCD
Unicode character database
User::grent
By-name interface to Perl's built-in getgr*() functions
User::pwent
By-name interface to Perl's built-in getpw*() functions
VMS::DCLsym
Perl extension to manipulate DCL symbols
VMS::Filespec
Convert between VMS and Unix file specification syntax
VMS::Stdio
Standard I/O functions via VMS extensions
Win32
Interfaces to some Win32 API Functions
Win32API::File
Low-level access to Win32 system API calls for files/dirs.
Win32CORE
Win32 CORE function stubs
XS::APItest
Test the perl C API
XS::Typemap
Module to test the XS typemaps distributed with perl
XSLoader
Dynamically load C libraries into Perl code
autodie::Scope::Guard
Wrapper class for calling subs at end of scope
autodie::Scope::GuardStack
Hook stack for managing scopes via %^H
autodie::Util
Internal Utility subroutines for autodie and Fatal
version::Internals
Perl extension for Version Objects
To find out all modules installed on your system, including those without documentation or outside the standard release, just use the following command (under the default win32 shell, double quotes should be used instead of single quotes).
    % perl -MFile::Find=find -MFile::Spec::Functions -Tlwe \
      'find { wanted => sub { print canonpath $_ if /\.pm\z/ },
      no_chdir => 1 }, @INC'
(The -T is here to prevent @INC from being populated by "PERL5LIB", "PERLLIB", and "PERL_USE_UNSAFE_INC".) They should all have their own documentation installed and accessible via your system man(1) command. If you do not have a find program, you can use the Perl find2perl program instead, which generates Perl code as output you can run through perl. If you have a man program but it doesn't find your modules, you'll have to fix your manpath. See perl for details. If you have no system man command, you might try the perldoc program.
Note also that the command "perldoc perllocal" gives you a (possibly incomplete) list of the modules that have been further installed on your system. (The perllocal.pod file is updated by the standard MakeMaker install process.)

Extension Modules

Extension modules are written in C (or a mix of Perl and C). They are usually dynamically loaded into Perl if and when you need them, but may also be linked in statically. Supported extension modules include Socket, Fcntl, and POSIX.
Many popular C extension modules do not come bundled (at least, not completely) due to their sizes, volatility, or simply lack of time for adequate testing and configuration across the multitude of platforms on which Perl was beta-tested. You are encouraged to look for them on CPAN (described below), or using web search engines like Google or DuckDuckGo.

CPAN

CPAN stands for Comprehensive Perl Archive Network; it's a globally replicated trove of Perl materials, including documentation, style guides, tricks and traps, alternate ports to non-Unix systems and occasional binary distributions for these. Search engines for CPAN can be found at https://www.cpan.org/
Most importantly, CPAN includes around a thousand unbundled modules, some of which require a C compiler to build. Major categories of modules are:
Language Extensions and Documentation Tools
Development Support
Operating System Interfaces
Networking, Device Control (modems) and InterProcess Communication
Data Types and Data Type Utilities
Database Interfaces
User Interfaces
Interfaces to / Emulations of Other Programming Languages
File Names, File Systems and File Locking (see also File Handles)
String Processing, Language Text Processing, Parsing, and Searching
Option, Argument, Parameter, and Configuration File Processing
Internationalization and Locale
Authentication, Security, and Encryption
World Wide Web, HTML, HTTP, CGI, MIME
Server and Daemon Utilities
Archiving and Compression
Images, Pixmap and Bitmap Manipulation, Drawing, and Graphing
Mail and Usenet News
Control Flow Utilities (callbacks and exceptions etc)
File Handle and Input/Output Stream Utilities
Miscellaneous Modules
You can find the CPAN online at <https://www.cpan.org/>

Modules: Creation, Use, and Abuse

(The following section is borrowed directly from Tim Bunce's modules file, available at your nearest CPAN site.)
Perl implements a class using a package, but the presence of a package doesn't imply the presence of a class. A package is just a namespace. A class is a package that provides subroutines that can be used as methods. A method is just a subroutine that expects, as its first argument, either the name of a package (for "static" methods), or a reference to something (for "virtual" methods).
A module is a file that (by convention) provides a class of the same name (sans the .pm), plus an import method in that class that can be called to fetch exported symbols. This module may implement some of its methods by loading dynamic C or C++ objects, but that should be totally transparent to the user of the module. Likewise, the module might set up an AUTOLOAD function to slurp in subroutine definitions on demand, but this is also transparent. Only the .pm file is required to exist. See perlsub, perlobj, and AutoLoader for details about the AUTOLOAD mechanism.

Guidelines for Module Creation

Do similar modules already exist in some form? If so, please try to reuse the existing modules either in whole or by inheriting useful features into a new class. If this is not practical try to get together with the module authors to work on extending or enhancing the functionality of the existing modules. A perfect example is the plethora of packages in perl4 for dealing with command line options. If you are writing a module to expand an already existing set of modules, please coordinate with the author of the package. It helps if you follow the same naming scheme and module interaction scheme as the original author.
Try to design the new module to be easy to extend and reuse. Try to "use warnings;" (or "use warnings qw(...);"). Remember that you can add "no warnings qw(...);" to individual blocks of code that need less warnings. Use blessed references. Use the two argument form of bless to bless into the class name given as the first parameter of the constructor, e.g.,:
 sub new {
     my $class = shift;
     return bless {}, $class;
 }
    
or even this if you'd like it to be used as either a static or a virtual method.
 sub new {
     my $self  = shift;
     my $class = ref($self) || $self;
     return bless {}, $class;
 }
    
Pass arrays as references so more parameters can be added later (it's also faster). Convert functions into methods where appropriate. Split large methods into smaller more flexible ones. Inherit methods from other modules if appropriate. Avoid class name tests like: "die "Invalid" unless ref $ref eq 'FOO'". Generally you can delete the "eq 'FOO'" part with no harm at all. Let the objects look after themselves! Generally, avoid hard-wired class names as far as possible. Avoid "$r->Class::func()" where using "@ISA=qw(... Class ...)" and "$r->func()" would work. Use autosplit so little used or newly added functions won't be a burden to programs that don't use them. Add test functions to the module after __END__ either using AutoSplit or by saying:
 eval join('',<main::DATA>) || die $@ unless caller();
    
Does your module pass the 'empty subclass' test? If you say "@SUBCLASS::ISA = qw(YOURCLASS);" your applications should be able to use SUBCLASS in exactly the same way as YOURCLASS. For example, does your application still work if you change: "$obj = YOURCLASS->new();" into: "$obj = SUBCLASS->new();" ? Avoid keeping any state information in your packages. It makes it difficult for multiple other packages to use yours. Keep state information in objects. Always use -w. Try to "use strict;" (or "use strict qw(...);"). Remember that you can add "no strict qw(...);" to individual blocks of code that need less strictness. Always use -w. Follow the guidelines in perlstyle. Always use -w.
Some simple style guidelines The perlstyle manual supplied with Perl has many helpful points. Coding style is a matter of personal taste. Many people evolve their style over several years as they learn what helps them write and maintain good code. Here's one set of assorted suggestions that seem to be widely used by experienced developers: Use underscores to separate words. It is generally easier to read $var_names_like_this than $VarNamesLikeThis, especially for non-native speakers of English. It's also a simple rule that works consistently with VAR_NAMES_LIKE_THIS. Package/Module names are an exception to this rule. Perl informally reserves lowercase module names for 'pragma' modules like integer and strict. Other modules normally begin with a capital letter and use mixed case with no underscores (need to be short and portable). You may find it helpful to use letter case to indicate the scope or nature of a variable. For example:
 $ALL_CAPS_HERE   constants only (beware clashes with Perl vars)
 $Some_Caps_Here  package-wide global/static
 $no_caps_here    function scope my() or local() variables
    
Function and method names seem to work best as all lowercase. e.g., "$obj->as_string()". You can use a leading underscore to indicate that a variable or function should not be used outside the package that defined it.
Select what to export. Do NOT export method names! Do NOT export anything else by default without a good reason! Exports pollute the namespace of the module user. If you must export try to use @EXPORT_OK in preference to @EXPORT and avoid short or common names to reduce the risk of name clashes. Generally anything not exported is still accessible from outside the module using the ModuleName::item_name (or "$blessed_ref->method") syntax. By convention you can use a leading underscore on names to indicate informally that they are 'internal' and not for public use. (It is actually possible to get private functions by saying: "my $subref = sub { ... }; &$subref;". But there's no way to call that directly as a method, because a method must have a name in the symbol table.) As a general rule, if the module is trying to be object oriented then export nothing. If it's just a collection of functions then @EXPORT_OK anything but use @EXPORT with caution.
Select a name for the module. This name should be as descriptive, accurate, and complete as possible. Avoid any risk of ambiguity. Always try to use two or more whole words. Generally the name should reflect what is special about what the module does rather than how it does it. Please use nested module names to group informally or categorize a module. There should be a very good reason for a module not to have a nested name. Module names should begin with a capital letter. Having 57 modules all called Sort will not make life easy for anyone (though having 23 called Sort::Quick is only marginally better :-). Imagine someone trying to install your module alongside many others. If you are developing a suite of related modules/classes it's good practice to use nested classes with a common prefix as this will avoid namespace clashes. For example: Xyz::Control, Xyz::View, Xyz::Model etc. Use the modules in this list as a naming guide. If adding a new module to a set, follow the original author's standards for naming modules and the interface to methods in those modules. If developing modules for private internal or project specific use, that will never be released to the public, then you should ensure that their names will not clash with any future public module. You can do this either by using the reserved Local::* category or by using a category name that includes an underscore like Foo_Corp::*. To be portable each component of a module name should be limited to 11 characters. If it might be used on MS-DOS then try to ensure each is unique in the first 8 characters. Nested modules make this easier. For additional guidance on the naming of modules, please consult:
    https://pause.perl.org/pause/query?ACTION=pause_namingmodules
    
or send mail to the <[email protected]> mailing list.
Have you got it right? How do you know that you've made the right decisions? Have you picked an interface design that will cause problems later? Have you picked the most appropriate name? Do you have any questions? The best way to know for sure, and pick up many helpful suggestions, is to ask someone who knows. The <[email protected]> mailing list is useful for this purpose; it's also accessible via news interface as perl.module-authors at nntp.perl.org. All you need to do is post a short summary of the module, its purpose and interfaces. A few lines on each of the main methods is probably enough. (If you post the whole module it might be ignored by busy people - generally the very people you want to read it!) Don't worry about posting if you can't say when the module will be ready - just say so in the message. It might be worth inviting others to help you, they may be able to complete it for you!
README and other Additional Files. It's well known that software developers usually fully document the software they write. If, however, the world is in urgent need of your software and there is not enough time to write the full documentation please at least provide a README file containing:
A description of the module/package/extension etc.
A copyright notice - see below.
Prerequisites - what else you may need to have.
How to build it - possible changes to Makefile.PL etc.
How to install it.
Recent changes in this release, especially incompatibilities
Changes / enhancements you plan to make in the future.
 
If the README file seems to be getting too large you may wish to split out some of the sections into separate files: INSTALL, Copying, ToDo etc.
Adding a Copyright Notice. How you choose to license your work is a personal decision. The general mechanism is to assert your Copyright and then make a declaration of how others may copy/use/modify your work. Perl, for example, is supplied with two types of licence: The GNU GPL and The Artistic Licence (see the files README, Copying, and Artistic, or perlgpl and perlartistic). Larry has good reasons for NOT just using the GNU GPL. My personal recommendation, out of respect for Larry, Perl, and the Perl community at large is to state something simply like:
 Copyright (c) 1995 Your Name. All rights reserved.
 This program is free software; you can redistribute it and/or
 modify it under the same terms as Perl itself.
    
This statement should at least appear in the README file. You may also wish to include it in a Copying file and your source files. Remember to include the other words in addition to the Copyright.
Give the module a version/issue/release number. To be fully compatible with the Exporter and MakeMaker modules you should store your module's version number in a non-my package variable called $VERSION. This should be a positive floating point number with at least two digits after the decimal (i.e., hundredths, e.g, "$VERSION = "0.01""). Don't use a "1.3.2" style version. See Exporter for details. It may be handy to add a function or method to retrieve the number. Use the number in announcements and archive file names when releasing the module (ModuleName-1.02.tar.Z). See perldoc ExtUtils::MakeMaker.pm for details.
How to release and distribute a module. If possible, register the module with CPAN. Follow the instructions and links on:
   https://www.cpan.org/modules/04pause.html
    
and upload to:
   https://pause.perl.org/
    
and notify <[email protected]>. This will allow anyone to install your module using the "cpan" tool distributed with Perl. By using the WWW interface you can ask the Upload Server to mirror your modules from your ftp or WWW site into your own directory on CPAN!
Take care when changing a released module. Always strive to remain compatible with previous released versions. Otherwise try to add a mechanism to revert to the old behavior if people rely on it. Document incompatible changes.

Guidelines for Converting Perl 4 Library Scripts into Modules

There is no requirement to convert anything. If it ain't broke, don't fix it! Perl 4 library scripts should continue to work with no problems. You may need to make some minor changes (like escaping non-array @'s in double quoted strings) but there is no need to convert a .pl file into a Module for just that.
Consider the implications. All Perl applications that make use of the script will need to be changed (slightly) if the script is converted into a module. Is it worth it unless you plan to make other changes at the same time?
Make the most of the opportunity. If you are going to convert the script to a module you can use the opportunity to redesign the interface. The guidelines for module creation above include many of the issues you should consider.
The pl2pm utility will get you started. This utility will read *.pl files (given as parameters) and write corresponding *.pm files. The pl2pm utilities does the following:
Adds the standard Module prologue lines
Converts package specifiers from ' to ::
Converts die(...) to croak(...)
Several other minor changes
 
Being a mechanical process pl2pm is not bullet proof. The converted code will need careful checking, especially any package statements. Don't delete the original .pl file till the new .pm one works!

Guidelines for Reusing Application Code

Complete applications rarely belong in the Perl Module Library.
Many applications contain some Perl code that could be reused. Help save the world! Share your code in a form that makes it easy to reuse.
Break-out the reusable code into one or more separate module files.
Take the opportunity to reconsider and redesign the interfaces.
In some cases the 'application' can then be reduced to a small fragment of code built on top of the reusable modules. In these cases the application could invoked as:
     % perl -e 'use Module::Name; method(@ARGV)' ...
or
     % perl -mModule::Name ...    (in perl5.002 or higher)
    

NOTE

Perl does not enforce private and public parts of its modules as you may have been used to in other languages like C++, Ada, or Modula-17. Perl doesn't have an infatuation with enforced privacy. It would prefer that you stayed out of its living room because you weren't invited, not because it has a shotgun.
The module and its user have a contract, part of which is common law, and part of which is "written". Part of the common law contract is that a module doesn't pollute any namespace it wasn't asked to. The written contract for the module (A.K.A. documentation) may make other provisions. But then you know when you "use RedefineTheWorld" that you're redefining the world and willing to take the consequences.

Recommended readings

Pages related to perlmodlib you should read also: