gnus: Checking New Groups

 
 1.4.1 Checking New Groups
 -------------------------
 
 Gnus normally determines whether a group is new or not by comparing the
 list of groups from the active file(s) with the lists of subscribed and
 dead groups.  This isn’t a particularly fast method.  If
 ‘gnus-check-new-newsgroups’ is ‘ask-server’, Gnus will ask the server
 for new groups since the last time.  This is both faster and cheaper.
 This also means that you can get rid of the list of killed groups (See
 Group Levels) altogether, so you may set ‘gnus-save-killed-list’ to
 ‘nil’, which will save time both at startup, at exit, and all over.
 Saves disk space, too.  Why isn’t this the default, then?
 Unfortunately, not all servers support this command.
 
    I bet I know what you’re thinking now: How do I find out whether my
 server supports ‘ask-server’?  No?  Good, because I don’t have a
 fail-safe answer.  I would suggest just setting this variable to
 ‘ask-server’ and see whether any new groups appear within the next few
 days.  If any do, then it works.  If none do, then it doesn’t work.  I
 could write a function to make Gnus guess whether the server supports
 ‘ask-server’, but it would just be a guess.  So I won’t.  You could
 ‘telnet’ to the server and say ‘HELP’ and see whether it lists
 ‘NEWGROUPS’ among the commands it understands.  If it does, then it
 might work.  (But there are servers that lists ‘NEWGROUPS’ without
 supporting the function properly.)
 
    This variable can also be a list of select methods.  If so, Gnus will
 issue an ‘ask-server’ command to each of the select methods, and
 subscribe them (or not) using the normal methods.  This might be handy
 if you are monitoring a few servers for new groups.  A side effect is
 that startup will take much longer, so you can meditate while waiting.
 Use the mantra “dingnusdingnusdingnus” to achieve permanent bliss.