Notes for installing Ruby on a fresh CentOS minimal install.
# assuming you logged in as root if not use:
# sudo
# update package manager
> yum update
# packages you'll need
> yum groupinstall "development tools"
> yum install httpd-devel openssl-devel zlib-devel curl-devel expat-devel gettext-devel readline-devel wget
# switch to src directory
> cd /usr/local/src
# get EPEL, you'll need EPEL (Extra Packages for Enterprise Linux) for libyaml and libyaml-devel
> wget http://dl.fedoraproject.org/pub/epel/6/x86_64/epel-release-6-7.noarch.rpm
# get ruby
> wget http://ftp.ruby-lang.org/pub/ruby/1.9/ruby-1.9.3-p194.tar.gz
# install EPEL
> rpm -Uvh epel-release-6-7.noarch.rpm
# install libyaml & libyaml-devel
> yum install libyaml-devel libyaml
# extract ruby
> tar xzvf ruby-1.9.3-p194.tar.gz
## start of ruby install
> cd ruby-1.9.3-p194
# configure --prefix=/usr/local is default but lets force it
> ./configure --prefix=/usr/local --enable-shared --disable-install-doc --with-opt-dir=/usr/local/lib
# make and then install
> make && make install
# if you mess up
# > make uninstall
# check ruby
> ruby -v
ruby 1.9.3p194 (2012-04-20) [x86_64-linux]
> which ruby
/usr/local/bin/ruby