[tex-live] how to update 2009 pretest

[Karl Berry]

    Could I upgrade the 2009 pretest just via "tlmgr update --all" without  
    affecting my stable TeXLive 2008 installation?

To the best of my knowledge, yes.

It may be that some critical bug appears at some point such that the 09
update won't work.  We'll see.  In any case, 08 should never be
affected, assuming you don't have anything (envvars, PATH) pointing to it.

k