Upgrade rbenv and ruby-build at first.
$ brew update $ brew upgrade rbenv ruby-build
Check available version list.
And install version 2.2.3 which is latest 2.2 stable version.
$ rbenv install --list $ rbenv install 2.2.3
It looks working.
$ rbenv shell 2.2.3 $ ruby -v ruby 2.2.3p173 (2015-08-18 revision 51636) [x86_64-darwin13]
