gistfile1.rb

require 'slop'

opts = Slop.parse do
  banner "ruby app.rb {clean,compile,start} [OPTIONS]"

  on :v, 'Display the version of App' do
    puts 'Version 1.5!'
    exit
  end

  on :V, :verbose, 'Enable verbose mode'

  on_empty do
    puts help
  end

  command :clean do
    on :v, 'Enable verbose mode'
    on :a, :all, 'Clean all?'
  end

  command :compile do
    banner "ruby app.rb compile [OPTIONS]"
    on :d, :dir, 'Out directory', true
    on :i, :items, 'Range of items. ex: 1,10', true, :as => Range
    on_empty do
      puts help
    end
  end
end

if opts[:compile].items? # check if option is present
  p opts[:compile][:items].to_a
end

# Try with the following for ARGV:
# ruby app.rb
# ruby app.rb -v
# ruby app.rb compile
# ruby app.rb compile -i 1,10
# many more ..