ruby ubuntu安装

看这里：
http://www.cnblogs.com/keen-allan/archive/2012/04/22/2464541.html

和这里：
https://www.digitalocean.com/community/tutorials/how-to-install-ruby-on-rails-on-ubuntu-12-04-lts-precise-pangolin-with-rvm

适用于ruby2.2.1,
使用rvm info命令可以查看已经安装的工具及安装的路径

此时输入ruby或irb
The program 'ruby' can be found in the following packages

解决方案

http://stackoverflow.com/questions/23590983/rails-installation-not-found

https://rvm.io/integration/gnome-terminal（这个是我采用的，最简单）
https://rvm.io/support/faq#shell_login

http://stackoverflow.com/questions/9056008/installed-ruby-1-9-3-with-rvm-but-command-line-doesnt-show-ruby-v

http://stackoverflow.com/questions/14135612/the-program-rails-can-be-found-in-the-following-packages-issue-with-some-app