There are instructions on how to install sshpass here:
https://gist.github.com/arunoda/7790979
For Mac you will need to install xcode and command line tools then use the unofficial Homewbrew command:
brew install https://raw.githubusercontent.com/kadwanev/bigboybrew/master/Library/Formula/sshpass.rb
~ Answered on 2015-08-27 19:59:03