How to tell which version of a gem a rails app is using

Question

I\'m investigating a rails app - the prod server has two version of a specific gem installed, how can I tell which version the prod app is using?

Answer 1

bundle exec gem which gem_name

Is probably what you can use:

$› bundle exec gem which rails
/Users/xxxx/.rvm/gems/ruby-2.1.2@gemset/gems/railties-4.1.7/lib/rails.rb