To use a Ruby installed with RVM in shell scripts, cron jobs, Keyboard Maestro& Alfred workflows, &c..
# Source RVM
if [[ -s "$HOME/.rvm/scripts/rvm" ]] ; then
elif [[ -s "/usr/local/rvm/scripts/rvm" ]] ; then
printf "ERROR: RVM doesn't seem to be installed.\n"
# Use a Ruby
rvm use 1.9.3-p194