Missing /dev/video devices in Linux

#!/bin/sh
cd /dev
for ii in 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 ; do
mknod video$ii c 81 $ii # char-major-81-[0-16]
  chown root:root video$ii
  chmod 770 video$ii
done