Mark all unticked articles in this group as read
(gnus-group-catchup-current).
gnus-group-catchup-group-hook is called when
catching up a group from the group buffer.
C
Mark
all articles in this group, even the ticked ones, as read
(gnus-group-catchup-current-all).
M-c
Clear the
data from the current group—nix out marks and the list of
read articles (gnus-group-clear-data).
M-x gnus-group-clear-data-on-native-groups
If
you have switched from one NNTP server to
another, all your marks and read ranges have become worthless.
You can use this command to clear out all data that you have on
your native groups. Use with caution.