csplit(1) on OpenBSD
The text 70a10ed1c2f9, as OpenBSD 5.4, OpenBSD 5.3, OpenBSD 5.2, OpenBSD 5.1, OpenBSD 5.0, OpenBSD 4.9 shipped it.
split files based on context
Flags it lists
-
-f -
-k -
-n -
-s