skyscribe:~$ rvm install 1.9.3
skyscribe:~$ rvm list

rvm rubies

   ruby-1.9.3-p125 [ i686 ]

# Default ruby not set. Try 'rvm alias create default <ruby>'.

# => - current
# =* - current && default
#  * - default

skyscribe:~$ rvm alias create default ruby-1.9.3-p125
Creating alias default for ruby-1.9.3-p125.
Recording alias default for ruby-1.9.3-p125.
Creating default links/files

skyscribe:~$ cat >> ~/.bashrc
[[ -s "$HOME/.rvm/scripts/rvm" ]] && . "$HOME/.rvm/scripts/rvm" # This loads RVM into a shell session.
^C
skyscribe:~$ bash
skyscribe:~$ rvm use 1.9.3
Using /home/skyscribe/.rvm/gems/ruby-1.9.3-p125
skyscribe:~$ ruby -v
ruby 1.9.3p125 (2012-02-16 revision 34643) [i686-linux]

• An experimental profile mode has been added. This is an implementation of many C++ standard library constructs with an additional analysis layer that gives performance improvement advice based on recognition of suboptimal usage patterns. For example,

  #include <vector>
  int main() 
  {
    std::vector<int> v;
    for (int k = 0; k < 1024; ++k) 
      v.insert(v.begin(), k);
  }
  

  When instrumented via the profile mode, can return suggestions about the initial size and choice of the container used as follows:

  vector-to-list: improvement = 5: call stack = 0x804842c ...
      : advice = change std::vector to std::list
  vector-size: improvement = 3: call stack = 0x804842c ...
      : advice = change initial container size from 0 to 1024
  

  These constructs can be substituted for the normal libstdc++ constructs on a piecemeal basis, or all existing components can be transformed via the -D_GLIBCXX_PROFILE macro.