11.1. Gems

In Chapter 1, Version Selection and Installation you have already seen that you can use the command gem install rails --version '~> 3.2.0' to install a current Rails 3.2. Gems constitute the package management in the world of Ruby. If a Ruby developer wants to offer a specific feature or a certain program or collection of programs to other Ruby developers, he can create a "gem" from these. This gem can then be installed via gem install. How to create a gem and where it can be hosted goes beyond the scope of this introduction chapter. The important thing for our purposes is that for example Rails in itself is also available as gem.

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