Perl module for extended processing of command line options

Getopt::Long with usage text

https://metacpan.org/release/Getopt-Long-Descriptive

Graph, the Perl module for graph operations

https://metacpan.org/release/Graph

GraphViz - Perl interface to the GraphViz graphing tool

https://metacpan.org/release/GraphViz

Simple and fast gzip and gunzip

https://metacpan.org/release/Gzip-Faster

Module to produce HTML 'breadcrumb trails'

https://metacpan.org/release/HTML-Breadcrumbs

Determine the encoding of HTML/XML/XHTML documents

https://metacpan.org/release/HTML-Encoding

Class that represents an HTML form element

https://metacpan.org/release/HTML-Form

HTML::Lint - check for HTML errors in a string or file

https://metacpan.org/release/HTML-Lint

High-performance, dynamic web site authoring system

https://metacpan.org/release/HTML-Mason

Perl module for handling CGI HTML paging of arbitrary data

https://metacpan.org/release/HTML-Pager

Perl5 module for parsing HTML documents

https://metacpan.org/release/HTML-Parser

Perl extension for scrubbing/sanitizing html

https://metacpan.org/release/HTML-Scrubber

This is a simple HTML link extractor

https://metacpan.org/release/HTML-SimpleLinkExtor

Perl5 module for strip HTML tag

https://metacpan.org/release/HTML-Strip

Generate HTML tables for CGI scripts

http://www.chime.ucl.ac.uk/~rmhiajp/htmltable/index.htm

Some useful data table in parsing HTML

https://metacpan.org/release/HTML-Tagset

Perl module to use HTML Templates from CGI scripts

https://metacpan.org/release/HTML-Template

Web validation in a Perl object using tidy

https://metacpan.org/release/HTML-Tidy

Collection of modules to manipulate HTML syntax trees

https://metacpan.org/release/HTML-Tree

HTTP Body Parser

https://metacpan.org/release/HTTP-Body

HTTP Cookie jars

https://metacpan.org/release/HTTP-Cookies

WebDAV client library

https://metacpan.org/release/HTTP-DAV

Simple HTTP server class

https://metacpan.org/release/HTTP-Daemon

Conversion routines for the HTTP protocol date formats

https://metacpan.org/release/HTTP-Date

PSGI compliant HTTP Entity Parser

https://search.mcpan.org/dist/HTTP-Entity-Parser/

Perl extension for faster implementation of HTTP::Headers

https://metacpan.org/release/HTTP-Headers-Fast

Perl5 modules for Lightweight HTTP implementation

https://metacpan.org/release/HTTP-Lite

Representation of HTTP style messages

https://metacpan.org/release/HTTP-Message

HTTP MultiPart Parser

https://search.mcpan.org/dist/HTTP-MultiPartParser/

Implementation of the HTTP content negotiation algorithm

https://metacpan.org/release/HTTP-Negotiate

Setup a CGI environment from a HTTP::Request

https://metacpan.org/release/HTTP-Request-AsCGI

Simple standalone HTTP daemon

https://metacpan.org/release/HTTP-Server-Simple

PSGI handler for HTTP::Server::Simple

https://metacpan.org/release/HTTP-Server-Simple-PSGI

Check the HTTP response code for a link

https://metacpan.org/release/HTTP-SimpleLinkChecker

Get the byte size of an internet resource

https://metacpan.org/release/HTTP-Size

Lightweight field hash implementation

https://metacpan.org/release/Hash-FieldHash

Flatten, unflatten complex data hashes

https://metacpan.org/pod/Hash::Flatten

Merges hashes

https://metacpan.org/release/Hash-Merge

Perl extension to provide the stuff missing in Hash::Util

https://metacpan.org/release/Hash-MoreUtils

Perl extension to store multiple values per key

http://search.cpan.org/dist/Hash-MultiValue/

Perl extensions for keeping data partially sorted

https://metacpan.org/release/Heap

Lexically scoped subroutine wrappers for Perl

https://metacpan.org/release/Hook-LexWrap

Abstract Base Class to build modules to capture output

https://metacpan.org/release/IO-Capture

Capture STDOUT/STDERR from subprocesses and XS/C modules

https://metacpan.org/release/IO-CaptureOutput

Perl5 compression modules (bzip2, deflate, gzip, zlib, zip)

https://metacpan.org/release/IO-Compress

Open an HTML file with automatic charset detection

https://metacpan.org/release/IO-HTML

Perl extension for working with IO::Handle like objects

https://metacpan.org/release/IO-Handle-Util

IO::Multiplex - Manage IO on many file handles

https://metacpan.org/release/IO-Multiplex

Portably create pipe() or pipe-like handles, one way or another

https://metacpan.org/release/IO-Pipely