first, you must be using --enable-incremental to do that. that's set at compile 
time.

second, you want the -r and -u options to remove and update, respectively.

John Paige scribbled on 5/12/05 11:04 AM:

> Hi,
>   I have a very basic question, somhow I cannot find it in the
> documentation (I must have missed it!)
> How do delete a document from an index? 
> For example, I have created an index xyz, added 10 documents to it. I
> want to update the same index xyz where I would like to add 2 more
> documents and delete the one that I indexed in the previous pass. How
> can I tell Swish to delete all the references to any document in an
> index?
> 
> Thanks,
> John

-- 
Peter Karman  .  http://peknet.com/  .  peter(at)not-real.peknet.com