If you need to quickly find out the version of OpenGL you have along with the version of GLSL you can use then run the following at the command line.
glxinfo | grep -e "OpenGL.*version string"
Remember that if you have 2 graphics cards that you will need to be aware of which one it will be checking. For me that meant running:
optirun glxinfo | grep -e "OpenGL.*version string"
As I am using Bumblebee to enable use of the optimus graphics setup.