OpenSSH 8.0 released

Along the same lines, I eventually started using the -R (--relative) flag to rsync in my most confident idempotent transfer mode:

rsync -avRP host:/prefix1/./rel1 host:/prefix2/./rel2 /prefix3/.

This creates /prefix3/rel1 and /prefix3/rel2 hierarchies with the easy to understand semantics that it splices the trees at the '.' point. Also, for me the --excludes/--includes patterns are easier to understand when I know they will be rooted at the '.' as well.