You can even use methods like map & select:

Ruby has this ENV object that behaves like a hash & it gives you access to all the environment variables that are available to you. Let’s discover how it works! Using Environment Variables in Ruby If you want to access these environment variables from Ruby there is a special object you can use. You can also print all the gem-specific variables & configuration with the gem env command. The list can be pretty long, but you don’t have to memorize it.

You can find a list of ALL your environment variables with the env command in Linux / Mac & the set command in Windows.

Making Rails start in test/development/production mode.

Defining where your operating system should look for binary files (.exe in Windows).

Passing API keys into your application, without having to commit them to source control (git).

Telling Ruby where to find gems ( GEM_PATH / GEM_HOME).That’s why it’s important to learn how they work & how to access them from your Ruby programs using the ENV special variable. We use these variables to share configuration options between all the programs in your computer. An environment variable is a key/value pair, it looks like this:

Ruby on rails windows vs mac