Canon provides canonicalization and pretty-printing for various serialization formats (XML, HTML, JSON, YAML), producing standardized forms suitable for comparison, testing, digital signatures, and human-readable output.

Carioca 2: is a complete rewrite who provide a full IoC/DI light Container and a services registry, build with logs, config and Internationalization facilities for designing your applications

cfndk is AWS Cloud Formation Development Kit

Fixed bug that was breaking paperclip and s3.

Display a diff of two files (long strings...) as html

Colloquy is an evented framework for building fast and efficient USSD applications in Ruby.

Calculate the structural similarity between two HTML documents

Changes the behavior of Sass's @import directive to only import a file once. Updated for Sass 3.7 compatibility.

Ruby Concordion

tool to align and merge two tables containing different parts of the same data

Use it with cucumber_fm-plugin (<= Rails 3.0) or cucumber_fm-engine (>= Rails 3.1)

Cukable allows running Cucumber test scenarios from FitNesse

A BDD tool written in Ruby

An Extension to Del.icio.us API using Ruby.

A Ruby wrapper for www.ofdb.de, a german movie indexing page like www.imdb.com.

The di(1) command wraps around GNU diff(1) to provide reasonable default settings and some original features.

Compare two text and decorate text differences.

Diff files with multiple engines and renderers.

Tools for taking and comparing responsive website snapshots

Doppelganger helps you to find areas of your code that are good places to refactor. It does this by finding methods and blocks that are duplicates or have less then a set threshold level of difference or be less then a specified percent different. This library can either be used with in another larger code metric/heuristic library, or called from the command line.