Delete local branches that have been merged into master.

clean_local_branches.rb

#!/usr/bin/env ruby

branches = %x(git fetch origin && git branch --merged master)
exclude  = /master|test|production|staging/

deletable = branches.split("\n").select { |branch| branch.strip !~ exclude }

if deletable.empty?
  puts 'nothing to delete :('
else
  deletable.each { |branch| p %x(git branch -d #{ branch.strip }) }
end