Installed Ruby 1.9.3 with RVM but command line doesn't show ruby -v

You have broken version of RVM. Ubuntu does something to RVM that produces lots of errors, the only safe way of fixing for now is to:

sudo apt-get --purge remove ruby-rvm
sudo rm -rf /usr/share/ruby-rvm /etc/rvmrc /etc/profile.d/rvm.sh

open new terminal and validate environment is clean from old RVM settings (should be no output):

env | grep rvm

if there was output, try to open new terminal, if it does not help then restart your computer.

install RVM:

\curl -L https://get.rvm.io | 
  bash -s stable --ruby --autolibs=enable --auto-dotfiles

If you find you need some hand-holding, take a look at Installing Ruby on Ubuntu 12.04, which gives a bit more explanation.

• Open Terminal.
• Go to Edit -> Profile Preferences.
• Select the Title & command Tab in the window opened.
• Mark the checkbox Run command as login shell.
• close the window and restart the Terminal.

Check this Official Link