https://blog.toright.com/posts/3564/%e9%80%8f%e9%81%8e-rvm-%e5%ae%89%e8%a3%9d-ruby-2-1-0-%e8%a7%a3%e6%b1%ba-centos-ruby-1-8-7-%e5%9f%b7%e8%a1%8c-sencha-cmd-%e6%9c%83%e3%80%8cregexp-buffer-overflow%e3%80%8d%e7%9a%84%e5%95%8f%e9%a1%8c