There aren’t many of these as yet, I’m afraid.
Edit the apply-to-all-groups all.SCORE file. You will be popped into
gnus-score-mode buffer (see Score File Editing).
Gnus maintains a cache of score alists to avoid having to reload them
all the time. This command will flush the cache
You can do scoring from the command line by saying something like:
$ emacs -batch -l ~/.emacs -l ~/.gnus.el -f gnus-batch-score