According to the tutorial, I can do things like !ls inside the Sage shell (in fact, here ls works).
But
echo $PATH
doesn't work whether I prepend a !, put it in quotes, whatever. How do I get such things to work, if at all? Is PATH just not defined in the Sage session?
(Secondarily, I'm trying to figure out how to put things in a path of a Sage session; sys.path seems to be the place to do it, but I'm not 100% sure of that.)
