Add the following line to your ~/.bash_profile:
[[ -r "$HOMEBREW_PREFIX/etc/profile.d/bash_completion.sh" ]] && . "$HOMEBREW_PREFIX/etc/profile.d/bash_completion.sh"
This formula is mainly for use with Bash 3. If you are using Homebrew's Bash or your
system Bash is at least version 4.2, then you should install `bash-completion@2` instead.