Basically, i'm looking to run Bitcoin Armory, and Litecoin on TailsDVD, with an LUKS encrypted SD card for persistence.
Right now, i'm practicing in xubuntu.
so how do i type in the "datadir" command in xubuntu?
First, i type "lsblk" to see the drives.
it lists my SD as:

sr0
/media/xub
mmcblk0
  mmcblk0p1
    luks-8928212337-8b5h-42h7-vg2f-f4e429jdn2k22(dm-1)
/media/xub

i tried this and it doesnt work:
./bitcoin-qt -datadir=/media/xub

Eventually, i want to run Armory on TailsDVD, but i gotta figure out the basics first...

Thanks for any help guys!