Reach the command line interface (text mode) at boot time

This work with Grub2:

• When you are on the bootloader, hover over your distribution name and press e (e for edit)
• You can now add options in the window that just opened
• On the line beginning with linux, add 3 at the end of the line (with a space)
• Press F10 to start

PS : This modification is temporary, next start up openSUSE will boot normaly.:x