Hi everyone...

Felt like installing macvim... according to the internet, it would be as simple as 'brew install macvim'.

bash-3.2$ brew install macvim

macvim: A full installation of Xcode.app is required to compile this software.

Installing just the Command Line Tools is not sufficient.

Xcode can be installed from the App Store.

Error: An unsatisfied requirement failed this build.

Oh, it wants the full XCode package, but I've just installed the CLI tools...   lets see if there is a binary package in Cask?

bash-3.2$ brew cask install macvim --override-system-vim

==> Downloading https://github.com/macvim-dev/macvim/releases/download/snapshot-77/MacVim-snapshot-77.tbz

######################################################################## 100.0%

==> Symlinking App 'MacVim.app' to '/Users/admin/Applications/MacVim.app'

==> Symlinking Binary 'mvim' to '/usr/local/bin/mvim'

🍺  macvim staged at '/opt/homebrew-cask/Caskroom/macvim/7.4-77' (1906 files, 35M)

Bingo... thanks Cask folks!