lock.rb

with_exclusive_lock("my_operation") do
	# Something that can only happen one at a time
end

def with_exclusive_lock(lock_name, &block)
	lock_file_name = "/tmp/#{lock_name}.lock"
	FileUtils.touch(lock_file_name)
	lock_file = File.new(lock_file_name)
	lock_file.flock(File::LOCK_EX)
	yield
	lock_file.flock(File::LOCK_UN)
end

Nice :)