On my server I did a search with sudo find . -name "application_controller.rb". There's so many files of that name. Which one should I edit so the changes will be reflected on my server?
./home/myapp/apps/myapp/releases/20140208000704/app/controllers/application_controller.rb
./home/myapp/apps/myapp/releases/20140116094931/app/controllers/application_controller.rb
./home/myapp/apps/myapp/releases/20140114154804/app/controllers/application_controller.rb
./home/myapp/apps/myapp/releases/20140117124202/app/controllers/application_controller.rb
./home/myapp/apps/myapp/releases/20140120094758/app/controllers/application_controller.rb
./home/myapp/apps/myapp/releases/20140116102758/app/controllers/application_controller.rb
./home/myapp/apps/myapp/releases/20140117125636/app/controllers/application_controller.rb
./home/myapp/apps/myapp/releases/20140116123905/app/controllers/application_controller.rb
./home/myapp/apps/myapp/releases/20140116115403/app/controllers/application_controller.rb
./home/myapp/apps/myapp/releases/20140117090645/app/controllers/application_controller.rb
./home/myapp/apps/myapp/releases/20140121091622/app/controllers/application_controller.rb
./home/myapp/apps/myapp/releases/20140212214841/app/controllers/application_controller.rb
./home/myapp/apps/myapp/releases/20140205001541/app/controllers/application_controller.rb
./home/myapp/apps/myapp/shared/cached-copy/app/controllers/application_controller.rb
./home/myapp/apps/myapp/shared/bundle/ruby/1.8/gems/best_in_place-1.1.2/test_app/app/controllers/application_co ntroller.rb
./home/myapp/apps/myapp/shared/bundle/ruby/1.8/gems/sass-rails-3.2.5/test/fixtures/sass_project/app/controllers /application_controller.rb
./home/myapp/apps/myapp/shared/bundle/ruby/1.8/gems/sass-rails-3.2.5/test/fixtures/engine_project/app/controlle rs/engine_project/application_controller.rb
./home/myapp/apps/myapp/shared/bundle/ruby/1.8/gems/sass-rails-3.2.5/test/fixtures/engine_project/test/dummy/ap p/controllers/application_controller.rb
./home/myapp/apps/myapp/shared/bundle/ruby/1.8/gems/sass-rails-3.2.5/test/fixtures/scss_project/app/controllers /application_controller.rb
./home/myapp/apps/myapp/shared/bundle/ruby/1.8/gems/devise-2.0.6/test/rails_app/app/controllers/application_con troller.rb
./home/myapp/apps/myapp/shared/bundle/ruby/1.8/gems/rest-graph-2.0.1/example/rails3/app/controllers/application _controller.rb
./home/myapp/apps/myapp/shared/bundle/ruby/1.8/gems/rest-graph-2.0.1/example/rails2/app/controllers/application _controller.rb
./home/myapp/apps/myapp/shared/bundle/ruby/1.8/gems/railties-3.2.3/lib/rails/generators/rails/app/templates/app /controllers/application_controller.rb
./home/myapp/apps/myapp/shared/bundle/ruby/1.8/gems/railties-3.2.3/guides/code/getting_started/app/controllers/ application_controller.rb
./home/myapp/apps/myapp/shared/bundle/ruby/1.8/gems/gmaps4rails-1.5.6/spec/dummy/app/controllers/application_co ntroller.rb
./home/myapp/.rvm/gems/ruby-1.8.7-p374/gems/best_in_place-1.1.2/test_app/app/controllers/application_controller.rb
./home/myapp/.rvm/gems/ruby-1.8.7-p374/gems/email_spec-1.2.1/examples/rails3_root/app/controllers/application_contr oller.rb
./home/myapp/.rvm/gems/ruby-1.8.7-p374/gems/sass-rails-3.2.5/test/fixtures/sass_project/app/controllers/application _controller.rb
./home/myapp/.rvm/gems/ruby-1.8.7-p374/gems/sass-rails-3.2.5/test/fixtures/engine_project/app/controllers/engine_pr oject/application_controller.rb
./home/myapp/.rvm/gems/ruby-1.8.7-p374/gems/sass-rails-3.2.5/test/fixtures/engine_project/test/dummy/app/controller s/application_controller.rb
./home/myapp/.rvm/gems/ruby-1.8.7-p374/gems/sass-rails-3.2.5/test/fixtures/scss_project/app/controllers/application _controller.rb
./home/myapp/.rvm/gems/ruby-1.8.7-p374/gems/devise-2.0.6/test/rails_app/app/controllers/application_controller.rb
./home/myapp/.rvm/gems/ruby-1.8.7-p374/gems/rest-graph-2.0.1/example/rails3/app/controllers/application_controller. rb
./home/myapp/.rvm/gems/ruby-1.8.7-p374/gems/rest-graph-2.0.1/example/rails2/app/controllers/application_controller. rb
./home/myapp/.rvm/gems/ruby-1.8.7-p374/gems/railties-3.2.3/lib/rails/generators/rails/app/templates/app/controllers /application_controller.rb
./home/myapp/.rvm/gems/ruby-1.8.7-p374/gems/railties-3.2.3/guides/code/getting_started/app/controllers/application_ controller.rb
./home/myapp/.rvm/gems/ruby-1.8.7-p374/gems/passenger-4.0.14/test/stub/rails3.0/app/controllers/application_control ler.rb
./home/myapp/.rvm/gems/ruby-1.8.7-p374/gems/passenger-4.0.14/test/stub/rails3.2/app/controllers/application_control ler.rb
./home/myapp/.rvm/gems/ruby-1.8.7-p374/gems/passenger-4.0.14/test/stub/rails2.3/app/controllers/application_control ler.rb
./home/myapp/.rvm/gems/ruby-1.8.7-p374/gems/passenger-4.0.14/test/stub/rails4.0/app/controllers/application_control ler.rb
./home/myapp/.rvm/gems/ruby-1.8.7-p374/gems/passenger-4.0.14/test/stub/rails3.1/app/controllers/application_control ler.rb
./home/myapp/.rvm/gems/ruby-1.8.7-p374/gems/passenger-4.0.14/test/stub/rails_apps/2.3/empty/app/controllers/applica tion_controller.rb
./home/myapp/.rvm/gems/ruby-1.8.7-p374/gems/passenger-4.0.14/test/stub/rails_apps/2.3/mycook/app/controllers/applic ation_controller.rb
myapp@myapp:/$ sufo nano ./home/myapp/.rvm/gems/ruby-1.8.7-p374/gems/passenger-4.0.14/test/stub/rails_apps/ 2.3/mycook/app/controllers/application_controller.rb
-bash: sufo: command not found
myapp@myapp:/$ sudo nano ./home/myapp/.rvm/gems/ruby-1.8.7-p374/gems/passenger-4.0.14/test/stub/rails_apps/ 2.3/mycook/app/controllers/application_controller.rb
myapp@myapp:/$
You shouldn't change any of them. Really.
./home/myapp/apps/myapp/releases suggests you are using something like Capistrano to deploy your application. You should update your source code, commit, and deploy it.
If that's not an option, then you should see if ./home/myapp/apps/myapp/current/app/controllers/application_controller.rb exists and edit that. If not, pick the most recent version in `./home/myapp/apps/myapp/releases.
Once edited you'll need to restart the web server for it to pick up the changes.
Again.. I would highly suggest not doing this unless you have no other option.