RubyGems is a packaging system for Ruby programs and libraries.
It packages Ruby libraries in a form that's easy for users to maintain and install.
RubyGems makes it easy to manage different versions of the same libraries on your machine.
You can install them with a single line at the command prompt.
Each individually packaged Ruby library or application is known as a gem or RubyGem.
Gems have names, version numbers, and descriptions.
You can manage your computer's local installations of gems using the gem command.