Unfortunately ruby-install won’t let you install Ruby version 1.8.7 any more. Here’s how to install it using ruby-build so that it could still be used by chruby:
brew install ruby-build brew install openssl libyaml libffi brew install apple-gcc42 brew install openssl098 # dependencies mkdir -p ~/.rubies # if doesn't exist brew link openssl098 --force # 1.8.7 requires OpenSSL 0.9.8 (or lower) ruby-build 1.8.7-p375 ~/.rubies/ruby-1.8.7 # compile 1.8.7-head (p375 is the same as HEAD) brew unlink openssl098 # revert symlinking chruby 1.8.7 # switch to 1.8.7