root@dur:~#
root@dur:~# ruby -v
ruby 1.8.7 (2011-06-30 patchlevel 352) [i686-linux]
root@dur:~#
root@dur:~# apt-get install ri1.9.1
Reading package lists... Done
Building dependency tree
Reading state information... Done
ri1.9.1 is already the newest version.
0 upgraded, 0 newly installed, 0 to remove and 388 not upgraded.
root@dur:~#
root@dur:~# cat /etc/lsb-release
DISTRIB_ID=Ubuntu
DISTRIB_RELEASE=12.04
DISTRIB_CODENAME=precise
DISTRIB_DESCRIPTION="Ubuntu 12.04.2 LTS"
root@dur:~#