Based on the manpage:
Request that the file-deletions on the receiving side be done incrementally as the transfer happens. The per-directory delete scan is done right before each directory is checked for updates, so it behaves like a more efficient --delete-before, including doing the deletions prior to any per-directory filter files being updated. This option was first added in rsync version 2.6.4. See --delete (which is implied) for more details on file-deletion.
--delete-after. I don't exactly understand the difference between these and
--delete. When does
--delete delete files, if not before, during, or after?
The docs also say:
Because of this, the default delete mode when you specify --delete is now --delete-during when both ends of the connection are at least 3.0.0 (use --del or --delete-during to request this improved deletion mode explicitly).
I suppose that means that
--del is intended to supercede
--delete. Is there any reason to use
--del? Could using
--del cause problems in connections that are less than 3.0.0? (I assume this is the rsync version).