Why are there two rake gemspecs in an rvm installation?

Why are there two rake gemspecs in an rvm installation?

~ - 10:59>find ~/.rvm/ -name 'rake-0.8.7.gemspec'
~/.rvm/gems/ruby-1.9.2-p136/specifications/rake-0.8.7.gemspec
~/.rvm/gems/ruby-1.9.2-p13开发者_如何学C6@global/specifications/rake-0.8.7.gemspec  # alias
~/.rvm/rubies/ruby-1.9.2-p136/lib/ruby/gems/1.9.1/specifications/rake-0.8.7.gemspec

Why are they different? (The non-gem version only contains the name and version).

Why doesn't the gem command always use the spec in the .rvm/gems dir, and how do I convince it to do so?

(This is a piece of the puzzle in order to solve this problem with installing ffi.

This has to do with the RVM concept of gemsets. It allows you have different groups of gem installs that you can make active.

Read more about gemsets here:

• https://rvm.io/gemsets/