Would it be possible to have an option to create the target folder on demand?
At the moment I'm using a somewhat dirty hack to make sure the target folder exists:
guard 'copy', :from => 'src/common/img', :to => 'build/img', :delete => true, :verbose => true do
puts "Starting to watch image files."
Dir.mkdir('build/img') unless File.directory?('build/img')
I also use Guard to create a build from scratch on the CI server on each commit where this is quite useful to have.
I've thought about a create option as well. The next thing on my todo list is to refactor the option validation, but I'll look into this after I finish that.