gnus: Group Levels

 
 2.6 Group Levels
 ================
 
 All groups have a level of “subscribedness”.  For instance, if a group
 is on level 2, it is more subscribed than a group on level 5.  You can
 ask Gnus to just list groups on a given level or lower (SeeListing
 Groups), or to just check for new articles in groups on a given level
 or lower (SeeScanning New Messages).
 
    Remember: The higher the level of the group, the less important it
 is.
 
 ‘S l’
      Set the level of the current group.  If a numeric prefix is given,
      the next N groups will have their levels set.  The user will be
      prompted for a level.
 
    Gnus considers groups from levels 1 to ‘gnus-level-subscribed’
 (inclusive) (default 5) to be subscribed, ‘gnus-level-subscribed’
 (exclusive) and ‘gnus-level-unsubscribed’ (inclusive) (default 7) to be
 unsubscribed, ‘gnus-level-zombie’ to be zombies (walking dead) (default
 8) and ‘gnus-level-killed’ to be killed (completely dead) (default 9).
 Gnus treats subscribed and unsubscribed groups exactly the same, but
 zombie and killed groups store no information on what articles you have
 read, etc.  This distinction between dead and living groups isn’t done
 because it is nice or clever, it is done purely for reasons of
 efficiency.
 
    It is recommended that you keep all your mail groups (if any) on
 quite low levels (e.g., 1 or 2).
 
    Maybe the following description of the default behavior of Gnus helps
 to understand what these levels are all about.  By default, Gnus shows
 you subscribed nonempty groups, but by hitting ‘L’ you can have it show
 empty subscribed groups and unsubscribed groups, too.  Type ‘l’ to go
 back to showing nonempty subscribed groups again.  Thus, unsubscribed
 groups are hidden, in a way.
 
    Zombie and killed groups are similar to unsubscribed groups in that
 they are hidden by default.  But they are different from subscribed and
 unsubscribed groups in that Gnus doesn’t ask the news server for
 information (number of messages, number of unread messages) on zombie
 and killed groups.  Normally, you use ‘C-k’ to kill the groups you
 aren’t interested in.  If most groups are killed, Gnus is faster.
 
    Why does Gnus distinguish between zombie and killed groups?  Well,
 when a new group arrives on the server, Gnus by default makes it a
 zombie group.  This means that you are normally not bothered with new
 groups, but you can type ‘A z’ to get a list of all new groups.
 Subscribe the ones you like and kill the ones you don’t want.  (‘A k’
 shows a list of killed groups.)
 
    If you want to play with the level variables, you should show some
 care.  Set them once, and don’t touch them ever again.  Better yet,
 don’t touch them at all unless you know exactly what you’re doing.
 
    Two closely related variables are ‘gnus-level-default-subscribed’
 (default 3) and ‘gnus-level-default-unsubscribed’ (default 6), which are
 the levels that new groups will be put on if they are (un)subscribed.
 These two variables should, of course, be inside the relevant valid
 ranges.
 
    If ‘gnus-keep-same-level’ is non-‘nil’, some movement commands will
 only move to groups of the same level (or lower).  In particular, going
 from the last article in one group to the next group will go to the next
 group of the same level (or lower).  This might be handy if you want to
 read the most important groups before you read the rest.
 
    If this variable is ‘best’, Gnus will make the next newsgroup the one
 with the best level.
 
    All groups with a level less than or equal to
 ‘gnus-group-default-list-level’ will be listed in the group buffer by
 default.  This variable can also be a function.  In that case, that
 function will be called and the result will be used as value.
 
    If ‘gnus-group-list-inactive-groups’ is non-‘nil’, non-active groups
 will be listed along with the unread groups.  This variable is ‘t’ by
 default.  If it is ‘nil’, inactive groups won’t be listed.
 
    If ‘gnus-group-use-permanent-levels’ is non-‘nil’, once you give a
 level prefix to ‘g’ or ‘l’, all subsequent commands will use this level
 as the “work” level.
 
    Gnus will normally just activate (i.e., query the server about)
 groups on level ‘gnus-activate-level’ or less.  If you don’t want to
 activate unsubscribed groups, for instance, you might set this variable
 to 5.  The default is 6.