Ruby - elementary OS

mati@laptop:~$ ruby -version
The program 'ruby' can be found in the following packages:
 * ruby1.8
 * ruby1.9.1
Try: sudo apt-get install <selected package>
 
mati@laptop:~$ gem -v
The program 'gem' can be found in the following packages:
 * ruby1.9.1
 * rubygems
Try: sudo apt-get install <selected package>
 
mati@laptop:~$