Where is the ruby standard library directory placed on a Mac?

I want to read some ruby code. And I think this is the good place to start dig in. But I cant find it.

Is Ruby installed by default on Mac?

First of all, Ruby is already pre-installed on your Mac. However, the pre-installed version is a few versions behind so we'll look into the other ways to install Ruby. Using a package management system makes your life easier when installing any software. On a Mac, you can use Homebrew to install newer versions of Ruby.

How do I run Ruby on Mac terminal?

Open Interactive Ruby If you're using macOS open up Terminal and type irb, then hit enter. If you're using Linux, open up a shell and type irb and hit enter. If you're using Windows, open Interactive Ruby from the Ruby section of your Start Menu.

And the way to discover weppos's answer is to launch a Terminal, run irb and enter