RubyGems

RubyGems is a package manager for the Ruby programming language. It provides a standard format for distributing Ruby programs and libraries as gems, and includes a central repository and a command-line tool to install, manage, and publish them.

A gem is a packaged Ruby application or library that includes code and metadata, defined in a gemspec file. Gems may declare dependencies on other gems, and can specify platform compatibility. The RubyGems system resolves and installs dependencies when you install a gem.

Key components include the gem command-line tool bundled with RubyGems, and the RubyGems.org repository that hosts thousands of gems. Users can install gems with gem install, search with gem search, list installed gems with gem list, update with gem update, and uninstall with gem uninstall. Gems can also be built with gem build and published with gem push.

Bundler is a separate tool frequently used with RubyGems to manage a project's gem dependencies through a Gemfile, ensuring reproducible environments. Bundler resolves versions and records them in a Gemfile.lock, while RubyGems handles the actual distribution and installation from RubyGems.org or other sources.

Publishing and maintenance: authors package their code into a .gem file using gem build and publish it to RubyGems.org with gem push, typically after creating a gemspec and configuring an API key. RubyGems.org provides metadata, versioning, and search features, and can enforce ownership controls and security practices.

Impact: RubyGems has become the de facto distribution mechanism for Ruby software, enabling a large ecosystem of reusable libraries and applications and helping developers share and reuse code across projects.