class Gem::Commands::WhichCommand

def initialize
  super 'which', 'Find the location of a library file you can require',
        :search_gems_first => false, :show_all => false
  add_option '-a', '--[no-]all', 'show all matching files' do |show_all, options|
    options[:show_all] = show_all
  end
  add_option '-g', '--[no-]gems-first',
             'search gems before non-gems' do |gems_first, options|
    options[:search_gems_first] = gems_first
  end
end