The gems I install via sudo gem install ... can\'t be executed (I get a command not found). They seem to install into /usr/local/Cellar/
sudo gem install ...
command not found
/usr/local/Cellar/
Instead of using => $(cd $(which gem)/..; pwd)
$(cd $(which gem)/..; pwd)
You could use this instead => $(brew --prefix ruby)/bin
$(brew --prefix ruby)/bin