brew install bash-completion

bash_completion

$ brew install bash-completion
==> Downloading http://bash-completion.alioth.debian.org/files/bash-completion-1.3.tar.bz2
######################################################################## 100.0%
==> ./configure --prefix=/usr/local/Cellar/bash-completion/1.3
==> make install
==> Caveats
Add the following lines to your ~/.bash_profile file:
  if [ -f `brew --prefix`/etc/bash_completion ]; then
    . `brew --prefix`/etc/bash_completion
  fi

To install Homebrew's own completion script:
  ln -s "/usr/local/Library/Contributions/brew_bash_completion.sh" "/usr/local/etc/bash_completion.d"
==> Summary
/usr/local/Cellar/bash-completion/1.3: 187 files, 1.0M, built in 9 seconds

@milligramme awesome! thanks

Very cool indeed 👍