
file "b_f1" => ["r_f4", "b_f2"] do |t|
    sys.touch t.name
end

file "b_f2" do |t|
    sys.touch t.name
end

task :clean do |t|
    sys.rm_f Dir["b_f*"]
end

subdirs %w(sub1 sub2)

:return_val
