gpsctl(1) on Linux
The text af7cd4ed103f, as Debian 10 (Buster) shipped it.
control the modes of a GPS
Flags it lists
-
-D -
-R -
-T -
-V -
-b -
-c -
-e -
-f -
-h -
-l -
-n -
-s -
-t -
-x