Setting the BASETOOLS variable on a separate line sets it for the life of the window.
Used on the same line sets it only for the following command.
I am not sure it matters in this case; I am reasonably confident I used the two line method when I fixed my problem.
Nice thing about having Galileo always up - you can test little things like this from the command line.
Using SSH from your tablet to Galileo, try:
BASE=/tmp
echo $BASE
cd $BASE
or the combined way:
BASE=~/
BASE=/tmp cd $BASE
echo $BASE (/tmp was only used for the combined command - ~/ is still set in window)