From OpenZFS on OS X
Assuming you already have Homebrew installed
brew install bash-completion
Add the following lines to your ~/.bash_profile:
if [ -f $(brew --prefix)/etc/bash_completion ]; then . $(brew --prefix)/etc/bash_completion fi
Install the ZFS bash completions:
cd /usr/local/etc/bash_completion.d curl -O https://raw.githubusercontent.com/zfsonlinux/zfs/master/contrib/bash_completion.d/zfs sudo chmod -R ugo+x /usr/local/etc/bash_completion.d/zfs
Open a new terminal window.