mode to allow eg vi or vim WITHIN *SHELL* -- forgot its name

[David Combs]

I think it was in a recent thread -- a mode-like .el-file that
once executed would all you to freely use cursor-moving 
programs like vi, vim, page, and the like, within an
ordinary *shell* window.

What was the name of it?   (And where to find it, too?)

THANK YOU SO VERY MUCH!!!

David