execute

# File lib/rubygems/commands/update_command.rb, line 87
  def execute
    if options[:system]
      update_rubygems
      return
    end

    hig = highest_installed_gems

    gems_to_update = which_to_update hig, options[:args].uniq

    if options[:explain]
      say "Gems to update:"

      gems_to_update.each do |(name, version)|
        say "  #{name}-#{version}"
      end

      return
    end

    say "Updating installed gems"

    updated = update_gems gems_to_update

    updated_names = updated.map { |spec| spec.name }
    not_updated_names = options[:args].uniq - updated_names

    if updated.empty?
      say "Nothing to update"
    else
      say "Gems updated: #{updated_names.join(' ')}"
      say "Gems already up-to-date: #{not_updated_names.join(' ')}" unless not_updated_names.empty?
    end
  end