Where does rails source file locate?

Hey guys I'm new to rails, I开发者_JS百科 read something about reading source code is good way to study rails, and I found the related rb file in rails' online document, such as this page But I can't find where the rails source file locate in my mac, could someone to help me out?

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Easiest way is to look online at the github repo

If you want to browse it locally, you can (depending on your version of rails) to a bundle show rails for Rails 3.0, this will tell you where it's installed.

For rails 2.3.x you just need to find out where the gem is installed and open that up. If you're using RVM for instance it will be somewhere in ~/.rvm