-v is incompatible with -g and does not compare test output files.
--s means to run only a single test and exit. This is useful when Purifying
-the Python interpreter. The file /tmp/pynexttest is read to find the next
-test to run. If this file is missing, the first test_*.py file in testdir or
-on the command line is used. (actually tempfile.gettempdir() is used instead
-of /tmp).
+-s means to run only a single test and exit. This is useful when doing memory
+analysis on the Python interpreter (which tend to consume to many resources to
+run the full regression test non-stop). The file /tmp/pynexttest is read to
+find the next test to run. If this file is missing, the first test_*.py file
+in testdir or on the command line is used. (actually tempfile.gettempdir() is
+used instead of /tmp).
"""