Quote Originally Posted by muhith
My USB key show up as 'sda' - how do I change to the sda via the command prompt?
If your USB key shows as 'sda', then partitions in it would show up as 'sda1', 'sda2', etc...

You must first mount a partition you want to use, and then you can access it at directory /mnt/sda1 or /media/sda1 for partition sda1 (I'm not sure which one your Knoppix-version uses).

If you see an icon on the desktop for your USB-key (e.g. labeled [sda1]) then just click on it, and that partition will be mounted automatically. You should also see the directory where it's mounted at (i.e. /mnt/sda1 or /media/sda1).
Then just use command cd /mnt/sda1 or cd /media/sda1 to change into that directory.