Sometimes you just want to add some extra functionality to some existing rake task.

So image having these rake tasks defined:

namespace :do do
  task :foo do
    puts "foo"
  end

  task :after do
    puts "after"
  end

  task :before do
    puts "before"
  end
end

We can prepend the do:before task to the do:foo task like this:

Rake::Task["do:foo"].enhance ["do:before"]

# output would be:
# before
# foo

And let something run after a task like this:

Rake::Task["do:foo"].enhance do
  Rake::Task["do:after"].invoke
end

# output would be:
# foo
# after

Really neat if you want to add some more stuff, to existing rails tasks for example. I got that idea from here, btw.