class Gem::Commands::UnpackCommand

def execute
  get_all_gem_names.each do |name|
    dependency = Gem::Dependency.new name, options[:version]
    path = get_path dependency
    unless path then
      alert_error "Gem '#{name}' not installed nor fetchable."
      next
    end
    if @options[:spec] then
      spec, metadata = get_metadata path
      if metadata.nil? then
        alert_error "--spec is unsupported on '#{name}' (old format gem)"
        next
      end
      spec_file = File.basename spec.spec_file
      open spec_file, 'w' do |io|
        io.write metadata
      end
    else
      basename = File.basename path, '.gem'
      target_dir = File.expand_path basename, options[:target]
      package = Gem::Package.new path
      package.extract_files target_dir
      say "Unpacked gem: '#{target_dir}'"
    end
  end
end