dependencies.rake

namespace :dependencies do
  task :pre_task do
    puts "pre-task"
  end

  task task1: :pre_task do
    puts "task1"
  end

  task task2: :pre_task do
    puts "task2"
  end

  task task3: :pre_task do
    puts "task3"
  end

  task meta_task: [:task1, :task2] do
    puts "meta task"
  end

  task all: [:meta_task, :task2, :task3] do
    puts "all"
  end
end

shell-output.txt

% rake dependencies:all
pre-task
task1
task2
meta task
task3
all