Right now I write to try to tell the world of the fix required to fsh when you install a recent (as of 2008) version of python. For me, the sarge -> etch debian upgrade broke fsh. You get the error message "ImportError: No module named FCNTL".
The fix is simple. You have to change "FCNTL" to "fcntl" in fshcompat.py. Do a global search and replace. That's it.
P.S. What do you call a fish with no eyes? A fsh.