Interact with Rails via Runner

The rails runner feature of the Ruby on Rails command line interface is pretty awesome.

The documentation states:

runner runs Ruby code in the context of Rails non-interactively.

Use it like the ruby command to execute Ruby code in the context of your Rails environment. Take this file:

# rails_runner_in_action.rb
puts Developer.count # 5
puts Post.count # 40
puts Channel.count # 17

And run it with:

$ rails runner rails_runner_in_action.rb
5
40
17

It also runs Ruby code right in the terminal, so this works (rails r is an alias):

$ rails r "puts Developer.count"
5

http://guides.rubyonrails.org/command_line.html#rails-runner