unix(4) on OpenBSD
The text fba90ee067e8, as OpenBSD 2.4, OpenBSD 2.3, OpenBSD 2.2, OpenBSD 2.1 shipped it.
UNIX-domain protocol family
The text fba90ee067e8, as OpenBSD 2.4, OpenBSD 2.3, OpenBSD 2.2, OpenBSD 2.1 shipped it.
UNIX-domain protocol family