watch(%r{^lib/(.+)\.rb$}) do |m| "spec/#{m[1]}_spec.rb" end ! # watch /spec/ files watch(%r{^spec/(.+)\.rb$}) do |m| "spec/#{m[1]}.rb" end end Guardfile $ bundle exec guard 09:53:55 - INFO - Guard is using Tmux to send notifications. 09:53:55 - INFO - Guard is using TerminalTitle to send notifications. 09:53:55 - INFO - Guard::RSpec is running 09:53:55 - INFO - Guard is now watching at '/path/to/Sinderella'