mountpoint(1) on Linux
The text 054268cfdf5e, as Debian 12 (Bookworm) shipped it.
see if a directory or file is a mountpoint
Flags it lists
-
--devno -
--fs-devno -
--help -
--nofollow -
--quiet -
--version -
-V -
-d -
-h -
-q -
-x