A quite easy way to launch several versions of sbt.
mkdir -p ~/bin
cd ~/bin
git clone git://github.com/seratch/xsbts.git
if [ ! `grep 'PATH=${PATH}:${HOME}/bin/xsbts' ${HOME}/.bash_profile` ]; then
echo "PATH=\${PATH}:\${HOME}/bin/xsbts" >> ${HOME}/.bash_profile
fi
source ~/.bash_profile