RVMの更新、Ruby 1.9.2p290の更新

# update rvm  
$ rvm get head  
# or older versions such as 1.0.0  
$ rvm update --head  
# you need to run reload to reflect the update  
$ rvm reload         
$ rvm -v
  rvm 1.7.2 by Wayne E. Seguin (wayneeseguin@gmail.com) [https://rvm.beginrescueend.com/]

# install ruby 1.9.2.p290  
$ rvm install 1.9.2-p290
  ...  
$ rvm list
  ruby-1.9.2-p0
  ruby-1.9.2-p180  
# you need to replace the p0 based on your environment  
$ rvm upgrade ruby-1.9.2-p0 ruby-1.9.2-p290
yes  
yes  
yes  ...  
Upgrade complete!  
$ rvm list
  ruby-1.9.2-p290 [ x86_64 ]  
$ rvm --default use 1.9.2
$ ruby -v
  ruby 1.9.2p290 (2011-07-09 revision 32553) [x86_64-darwin10.8.0]