I tried also with mounting - it seems this device already exists
Code:
# mkdir /var/sysfs
mkdir: Cannot create directory `/var/sysfs': File exists
# mount sys /var/sysfs -t sysfs
mount: Mounting sys on /var/sysfs failed: Device or resource busy
# mknod -m 640 /dev/sda b 8 0
mknod: /dev/sda: File exists
# ./sd.sh
# ./spindown.sh: ./spindown.sh: 32: head: not found
./spindown.sh: ./spindown.sh: 32: awk: not found
Error: no sysfs found.