Railsアプリケーションの環境変数を確認する方法

手順

1. rails console を起動

$ rails console

2. ENV オブジェクトを確認

# キーを指定して表示
irb(main):005:0> ENV['RAILS_ENV']
=> "development"

# 全て表示
irb(main):001:0> ENV
=>
{"BUNDLER_ORIG_BUNDLER_VERSION"=>"BUNDLER_ENVIRONMENT_PRESERVER_INTENTIONALLY_NIL",
 "BUNDLER_ORIG_BUNDLE_BIN_PATH"=>"BUNDLER_ENVIRONMENT_PRESERVER_INTENTIONALLY_NIL",
 "BUNDLER_ORIG_BUNDLE_GEMFILE"=>"BUNDLER_ENVIRONMENT_PRESERVER_INTENTIONALLY_NIL",
 "BUNDLER_ORIG_GEM_HOME"=>"BUNDLER_ENVIRONMENT_PRESERVER_INTENTIONALLY_NIL",
 "BUNDLER_ORIG_GEM_PATH"=>"BUNDLER_ENVIRONMENT_PRESERVER_INTENTIONALLY_NIL",
 "BUNDLER_ORIG_MANPATH"=>"BUNDLER_ENVIRONMENT_PRESERVER_INTENTIONALLY_NIL",
 "RAILS_ENV"=>"development"}

参考