vis(1) on OpenBSD
The text e04283eceffc, as OpenBSD 3.3, OpenBSD 3.2, OpenBSD 3.1, OpenBSD 3.0, OpenBSD 2.9, OpenBSD 2.8, OpenBSD 2.7 shipped it.
display non-printable characters in a visual format
Flags it lists
-
-F -
-b -
-c -
-f -
-l -
-n -
-o -
-s -
-t -
-w