"Uff" (expression of exhaustion...), I think I've just found the subtle cause of a remaining bug in my py4gretl functions, leading to temp files not being deleted on windows. The following python call (shell command) fails: ! python -c 'import os; os.remove("testhome.txt")' while swapping the single/double quotes works: ! python -c "import os; os.remove('testhome.txt')" I guess this is actually a windows shell thing (because the functions worked ok on Linux IIRC), does anybody know something about that stuff? Or does gretl parsing play a role, too? Thanks, Sven