This package provides a implementations of custom cops that are bundled as defaults in Standard Ruby.

Pry is an IRB alternative and runtime developer console for Ruby. It features syntax highlighting, a plugin architecture, runtime invocation, and source and documentation browsing.

Psych is a YAML parser and emitter. Psych leverages libyaml for its YAML parsing and emitting capabilities. In addition to wrapping libyaml, Psych also knows how to serialize and de-serialize most Ruby objects to and from the YAML format.

HTTP::Cookie is a Ruby library to handle HTTP Cookies based on RFC 6265. It has been designed with security, standards compliance and compatibility in mind, to behave just the same as today's major web browsers. It has built-in support for the legacy cookies.txt and cookies.sqlite formats of Mozilla Firefox.

RJB is a bridge program that connects Ruby and Java via the Java Native Interface.

This Ruby library uses ANSI escape sequences to control the attributes of terminal output.

This package provides C extensions to optimize the concurrent-ruby gem when running under the Matz's Ruby Interpreter (MRI, also known as CRuby).

Shindo is a simple depth first testing library for Ruby.

Timers offers a collections of one-shot and periodic timers, intended for use with event loops such as async.

This library provides functions to calculate the differences between two tree-like structures. It is similar to Ruby's built-in TSort module.

This library provides functionality to send Internet mail via SMTP, the Simple Mail Transfer Protocol. The SMTP protocol specification is known as RFC2821.

This package can speed up Test::Unit, RSpec, Cucumber, and Spinach tests by running them concurrently across multiple CPU cores.

Net::HTTP::Persistent manages persistent HTTP connections using Net::HTTP, supporting reconnection and retry according to RFC 2616.

This package provides a common interface to multiple JSON libraries, including Oj, Yajl, the JSON gem (with C-extensions), the pure-Ruby JSON gem, NSJSONSerialization, gson.rb, JrJackson, and OkJson.

Erubi is a ERB template engine for Ruby. It is a simplified fork of Erubis

PandocRuby is a wrapper for Pandoc, a Haskell library with command line tools for converting one markup format to another. Pandoc can convert documents from a variety of formats including markdown, reStructuredText, textile, HTML, DocBook, LaTeX, and MediaWiki markup to a variety of other formats, including markdown, reStructuredText, HTML, LaTeX, ConTeXt, PDF, RTF, DocBook XML, OpenDocument XML, ODT, GNU Texinfo, MediaWiki markup, groff man pages, HTML slide shows, EPUB, Microsoft Word docx, and more.

This library provides a way to run code around tests in Minitest, written using either the unit test or spec style.

Aruba is an extension for Cucumber, RSpec and Minitest for testing command-line applications. It supports applications written in any language.

Metaclass is a Ruby library adding a metaclass method to all Ruby objects.

Skinny is a simple, upgradable WebSockets for Ruby, using the Thin library.

This library uses the output of the ps command to create a process tree data structure for the current host.

IRB is an interactive Ruby command-line tool for REPL (Read Eval Print Loop).

This gem generates a treemap showing the complexity of Ruby code on which it is run. It uses Saikuro under the covers to analyze Ruby code complexity.

Shoulda Matchers provides RSpec- and Minitest-compatible one-liners that test common Rails functionality. These tests would otherwise be much longer, more complex, and error-prone.