readline also seems to have a "kill ring":

    $ aaa ^U
    # now "aaa" is the only thing in the kill ring
    $ bbb ^U
    # now kill ring is ["aaa", "bbb"]
    $ ccc ^U
    # now kill ring is ["aaa", "bbb", "ccc"]
    $ ^Y
    $ ccc
    # alt+y cycles through the kill ring
    $ bbb Alt+Y
    $ aaa Alt+Y
    $ ccc Alt+Y
    $ bbb

etc. This likely feels completely natural if you're an emacs user. I don't know what the equivalent vi thing is.