$ rvm migrate from to
Efficiently moves the gems from one ruby to another. Like 'rvm gemset copy' but removes the gems from the source ruby afterwards and runs it against all gemsets for a given ruby.
Examples:
To migrate all gemsets from rc2 of 1.9.2 to the first release, p0, you would run:
$ rvm migrate 1.9.2-rc2 1.9.2-p0
append --force to answer yes to all questions.