I bought a new Mac (:P) in these days, and I found that Leopard built-
in rails 1.2.6
But it’s rails 2.2.2 right now, so I upgraded Rubygems before I
upgraded rails…
and after I upgraded Rubygems and Rails… I run “gem clean” and got
the error message:
bash-3.2# gem clean
Cleaning up installed gems…
Attempting to uninstall rails-1.2.6
ERROR: While executing gem … (Gem::InstallError)
Unknown gem rails = 1.2.6
hmm… I don’t know how to solve it 
Could anyone tell me how to solve it? thanks!