uninstall one distribution without affecting the others

edit

I accidently install indigo distribution while I already have hydro. I wonder if the uninstallation of the indigo distribution would affect the dependencies of hydro. Also, I type: {echo "sourcee /opt/ros/fuerte/setup.bash" >> ~/.bashrc } instead of {echo "source /opt/ros/fuerte/setup.bash" >> ~/.bashrc} and the terminal still show source: command not found. How can I fix the command?