How I installed Ruby on a clean Mac (August 2015)

howtoruby.md

First prepare your Mac for Developer Mode™.

• xcode-select --install (now all sorts of stuff works)
• Install homebrew

Install rbenv and use it to install a Ruby:

• brew install rbenv ruby-build
• echo 'eval "$(rbenv init -)"' >> ~/.bash_profile
• rbenv install <whatever ruby version>

Now you can install Gems.

If you're a Ruby developer, the first thing you should do is install bundler. If you're an iOS developer, the first thing you probably want to do is install cocoapods.

• gem install bundler or gem install cocoapods
• rbenv rehash (now bundler or cocoapods or whatever will have a rbenv shim on the PATH)

Finally, if you depend on Postgres (of course you do):

• Install Postgres.app. Add its /bin directory to your PATH
• gem install -v <whatever version your Gemfile[.lock] demands> pg -- --with-pg-config=/Applications/Postgres.app/Contents/Versions/9.4/bin/pg_config

Now you can bundle install inside your Rails project.