irb -rubygems
irb(main):001:0> require 'mustache'
=> true
irb(main):002:0> Mustache.render('This is a {{#test}}truthy{{/test}} string!', { :test => '' })
=> "This is a truthy string!"
irb(main):003:0> Mustache.render('This is a {{#test}}truthy{{/test}} string!', { :test => nil })
=> "This is a string!"