安装编译环境

yum groupinstall "Development tools"
或者

yum install gcc gcc-c++ gcc-g77 flex bison autoconf automake bzip2-devel zlib-devel ncurses-devel libjpeg-devel libpng-devel libtiff-devel freetype-devel pam-devel openssl-devel libxml2-devel gettext-devel pcre-devel

删除已经安装的项目：

yum erase ruby ruby-libs ruby-mode ruby-rdoc ruby-irb ruby-ri ruby-docs

安装依赖：

yum -y install zlib-devel curl-devel openssl-devel httpd-devel apr-devel apr-util-devel mysql-devel

下载Ruby源码并解压缩：

wget http://cache.ruby-lang.org/pub/ruby/2.1/ruby-2.1.5.tar.gztar zxvf ruby-2.1.5.tar.gz

编译安装：

cd ruby-2.1.5
./configure
make
make install

检查安装：

ruby -v