Preventing rsync from picking up rsync temp files.

If you have multiple vias in your rsync path (e.g. a -> b -> c) you
can use an rsync filter rule to tell rsync: don’t transfer files that
have . in the beginning of the filename!

–filter ‘- .*’

This way you won’t have rsync temp files (named something like
.filename.xxyyzz) from the a -> b transfer ending up on c.