12-ckmount

#!/usr/bin/env sh
# Purpose: determine device on which 'boot' is mounted
# REF: https://unix.stackexchange.com/a/217412/286615
device1="/dev/nvme0n1p1"
device2="/dev/mmcblk0p1"
#
if mountpoint=$(findmnt -nr -o target -S "$device1"); then
  printf 'Using NVME:\t"%s" is mounted on "%s"\n' "$mountpoint" "$device1"

elif mountpoint=$(findmnt -nr -o target -S "$device2"); then
  printf 'Using SD card:\t"%s" is mounted on "%s"\n' "$mountpoint" "$device2"

else
  printf '"%s" does not appear to be directly mounted\n' "$device"
fi