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

In the terminal

  bundle show 
  bundle show | grep 

or

  gem list | grep 

For example:

  bundle show rails
  bundle show | grep rails

  gem list | grep rails