require 'rake/clean' file 'reveal.js/index.html' do `git submodule init` `git submodule update` end CLOBBER.include 'reveal.js' task :clobber do # Spirit of clobber is to bring repository back to pristine state # after cloning. If that's the case, then we want to rm -r reveal.js # && mkdir reveal.js. By observation, redefining the task :clobber # and adding this mkdir achieves that mkdir 'reveal.js' end