This feature and keyword are not available in LISTSERV Lite.
This keyword makes it possible to define a "super-list" (as in opposite of sub-list), that is, a "container" list that includes all the subscribers in a predefined set of sub-lists. This can be done recursively to any depth.
Site maintainers can create super-lists consisting of any of the lists on the server, regardless of who owns them.
A non-maintainer list owner may convert a standard list that they own into a super-list, but may add only other lists that they own to the Sub-Lists= setting. Attempts by non-maintainer list owners to add non-owned lists to their super-list will result in an error when the list configuration is stored and the configuration will be left unchanged.
The value is a comma separated list of all the sub-lists, which must all be on the same (local) machine. For instance:
* Sub-lists= MYLIST-L,MYOTHERLIST-L
or (if you want to put each sublist on a separate line):
* Sub-lists= MYLIST-L
* Sub-lists= MYOTHERLIST-L
The default value for this keyword is null, that is, to have no sublists. Please note that the super-list and all of its sublists must reside on the same LISTSERV server.
The only difference between a normal list and a super-list is what happens when you post to it. With the super-list, the membership of all the sub-lists is added (recursively) and duplicates are suppressed. Other than that, the super-list is a normal list with its own archives, access control, etc. You can even subscribe to it, and this is actually an important aspect of the operation of super-lists. If you are subscribed to the super-list itself, the subscription options used to deliver super-messages to you are taken from your subscription to the super-list, just like with any other list. All combinations are allowed, and in particular NOMAIL is allowed, meaning you don't want to get messages posted to the super-list. When you are subscribed to multiple sub-lists, on the other hand, things work differently:
- NOMAIL subscriptions are ignored. You will get the super-message if you have an active (not NOMAIL) subscription to at least one sub-list. The idea is that the super-message must be equivalent to posting to all the sub-lists, without the duplicates. Since all it takes to get a message posted to all the sub-lists is a single non-NOMAIL subscription, this is how the super-list works. The only way not to get the super-messages is to subscribe to the super-list directly and set yourself to NOMAIL.
- The DIGEST and INDEX options are ignored and internally converted to MAIL. The first reason is that, since in most cases the user will be on multiple sub-lists (otherwise you don't need a super-list in the first place), the only safe method to set subscription options for super-messages is by subscribing to the super-list so that there is no ambiguity. The second reason is that, in most cases, super-lists will be used for out of band administrative messages rather than for large volume discussions, so it is actually preferable to have the message sent directly. The third reason is that the super-list and sub-lists may not necessarily offer the same options (DIGEST and INDEX). In particular it is expected that many super-lists will not have archives. If you want a DIGEST or INDEX for the super-messages, you must subscribe to the super-list directly.
- The REPRO option, if set, is inherited by sub-lists. That is to say, if the sub-list subscriber is set to REPRO on the sub-list AND the super-list is set up such that sub-list subscribers may post directly to it, he will receive a copy of his own posting. (That is, notwithstanding issues outside of LISTSERV's ability to control on the receiving end that may make REPRO messages impossible to receive, such as is experienced by many Gmail users.)
Topics, if defined, are evaluated on a per-list basis. That is, for every sub-list (and for the super-list), LISTSERV determines whether the topic of the message is one that you want to see. If not, it acts as if you were not subscribed to this particular list. Roughly speaking, this works very well if all the sub-lists have the same set of topics (or a well-defined set of common topics), and doesn't work well at all if every list has its own set of topics.