vis(1) on OpenBSD
The text c05f517d64a1, as OpenBSD 3.7, OpenBSD 3.6, OpenBSD 3.5, OpenBSD 3.4 shipped it.
display non-printable characters in a visual format
Flags it lists
-
-F -
-b -
-c -
-f -
-l -
-n -
-o -
-s -
-t -
-w