socat(1) on Linux
The text a5ba591fdd56, as Debian 11 (Bullseye) shipped it.
Multipurpose relay (SOcket CAT)
Flags it lists
-
-4 -
-6 -
-? -
-?? -
-??? -
-D -
-R -
-U -
-V -
-d -
-g -
-h -
-hh -
-hhh -
-lh -
-lm -
-ls -
-lu -
-ly -
-r -
-s -
-u -
-v -
-x