I am not specifically familiar with openSUSE, since I use mostly Slackware, but in general the grub command line is made easier to use because it has an autocomplete function (use the "tab" key).
As you'll find in your /boot/grub/menu.lst, in general (and most likely openSUSE is the same), to boot in grub you need:
root (hdnum designationsometimes letter - but this is more often for BSD variants)
so type boot and tab -> grub will give you a choice of possibilities for your computer. Remember that in grub the numbering system starts at 0, so you drive "hda" will be "hd0";"hdb" will be "hd1" and so on.
After choosing a number you do tab again, then grub will offer you the choices for partitions on that drive i,e hd0,0 will be hda1, etc
Do the same for kernel and initrd and then enter the command "boot"
If your entries are right, then you will boot into your OS, if not try again.
Grub "failure" that allows you to go to the command line is usually a problem with the entries on /boot/grub/menu.lst so after you do get into your OS, check that file and edit it. The use of a live distro can make this a lot easier.
Hope this helps . .