Check the server(s) for new articles. If the numerical prefix is used,
this command will check only groups of level arg and lower
(gnus-group-get-new-news). If given a non-numerical prefix, this
command will force a total re-reading of the active file(s) from the
back end(s).
Check whether new articles have arrived in the current group
(gnus-group-get-new-news-this-group).
gnus-goto-next-group-when-activating says whether this command is
to move point to the next group or not. It is t by default.
Activate absolutely all groups (gnus-activate-all-groups).
Restart Gnus (gnus-group-restart). This saves the .newsrc
file(s), closes the connection to all servers, clears up all run-time
Gnus variables, and then starts Gnus all over again.
gnus-get-new-news-hook is run just before checking for new news.
gnus-after-getting-new-news-hook is run after checking for new
news.