Process marks are
displayed as # in the summary buffer, and are used
for marking articles in such a way that other commands will
process these articles. For instance, if you process mark four
articles and then use the * command, Gnus will enter
these four articles into the cache. For more information, see
Process/Prefix.
gnus-summary-mark-as-processable). gnus-summary-unmark-as-processable).gnus-summary-unmark-all-processable).gnus-uu-invert-processable).Subject header that matches a
regular expression
(gnus-uu-mark-by-regexp).Subject header that matches a
regular expression
(gnus-uu-unmark-by-regexp).gnus-uu-mark-region).gnus-uu-unmark-region).gnus-uu-mark-thread).gnus-uu-unmark-thread).gnus-uu-mark-over).gnus-uu-mark-series).gnus-uu-mark-sparse).gnus-uu-mark-all).gnus-uu-mark-buffer).gnus-summary-kill-process-mark).gnus-summary-yank-process-mark).gnus-summary-save-process-mark).Also see the & command in Searching for Articles, for how to set process marks based on article body contents.