show_help

# File lib/rubygems/commands/help_command.rb, line 373
  def show_help # :nodoc:
    command = @command_manager[options[:help]]
    if command then
      # help with provided command
      command.invoke("--help")
    else
      alert_error "Unknown command #{options[:help]}.  Try 'gem help commands'"
    end
  end