Keymaps and Emacs and libreadline ?

[It's me FKtPp ;)]

Hi group:

  I have GNU Emacs installed in all my computers, and I'd love to do
  every thing Emacs's way. But, when I try use libreadline to edit
  shell commands. Problem comes boring me :( This was what I
  encountered:

  I setup-ed libreadline so that I can use Emacs key-binding and
  key-sequences to edit shell command lines. It works perfect in
  X-terminal, but, when I switch to console mode(not X) the right-alt
  key no longer act as a meta key like what left-alt key do :( I
  viewed the keymap files and find out:

    Keycode 56 = Alt
    Keycode 100 = AltGr

  What's the meaning of "AltGr"?? Why map right-alt to AltGr? And I
  also find out that left-ctrl and right-ctrl both mapped to
  control. Why ctrl keys different from alt keys?

  How can I configure right-alt do the same work as the left-alt do?
  change keymap or change inputrc??

Thank you for ur help !! And sorry for my poor English :P