When mutex_m is required, any object that extends or includes Mutex_m will be treated like a Mutex.

WEBrick is an HTTP server toolkit that can be configured as an HTTPS server, a proxy server, and a virtual-host server.

Archive::Tar::Minitar is a pure-Ruby library and command-line utility that provides the ability to deal with POSIX tar archive files.

Timeout provides a way to auto-terminate a potentially long-running operation if it hasn't finished in a fixed amount of time.

Daemons provides a way to wrap existing Ruby scripts to be run as a daemon and to be controlled by simple start/stop/restart commands.

This package provides a set of Hoe plugins for tighter Git integration. It provides tasks to automate release tagging and pushing and changelog generation.

Builder provides a number of builder objects that make it easy to create structured data. Currently the following builder objects are supported: XML Markup and XML Events.

This package provides a Ruby binding to the Ed25519 elliptic curve public-key signature system described in RFC 8032.

Hamster provides 6 persistent data structures: Hash, Vector, Set, SortedSet, List, and Deque (which works as an immutable queue or stack).

This package containse the XML parsing tools shared between a number of providers in the fog gem. fog is a Ruby cloud services library.

Spinach is a high-level BDD framework that leverages the expressive Gherkin language to help you define executable specifications of your code.

MessagePack is a binary-based efficient object serialization library. It enables to exchange structured objects between many languages like JSON. Unlike JSON, it is very fast and small.

This library provides functionality for retrieving email via POP3, the Post Office Protocol version 3, as specified by RFC1939.

The ammeter gem makes it easy to write specs for Rails generators. An existing user is rspec-rails, which uses ammeter to spec its own generators.

Promise is a Ruby implementation of the Promises/A+ specification. It provides 100% mutation coverage, tested on MRI 1.9, 2.0, 2.1, 2.2, Rubinius, and JRuby.

This library provides methods to encode and decode Ascii85 binary-to-text encoding. The main modern use of Ascii85 is in PostScript and Portable Document Format (PDF) file formats.

Markaby allows writing HTML packages in pure Ruby. This is similar to the functionality provided by ERB, but without the mixture of HTML and additional ERB syntax.

Launchy is helper class for launching applications in a fire and forget manner. The aim of Launchy is to provide a common approach to launching external applications from within Ruby programs.

Net::SSH is a pure-Ruby implementation of the SSH2 client protocol. It allows you to write programs that invoke and interact with processes on remote servers, via SSH2.

Fivemat is a MiniTest/RSpec/Cucumber formatter that gives each test file its own line of dots during testing. It aims to provide test output that is neither too verbose nor too minimal.

Gettext is a GNU gettext-like program for Ruby. The catalog file (po-file) used is the same as that used by GNU gettext, allowing you to use GNU gettext tools for maintenance.

This package is a Ruby parser library for Gemtext (hypertext format which is intended to serve as the native response format of the Gemini file transfer protocol) and produces a document object of various nodes.

The mapping gem maps model objects based on their class to a given output model. It is useful for versioning external interfaces (e.g. JSON APIs) or processing structured data from one format to another.

Timecop provides "time travel" and "time freezing" capabilities, making it easier to test time-dependent code. It provides a unified method to mock Time.now, Date.today, and DateTime.now in a single call.