Ubuntu update disk configuration via hdparm to disable power management to prevent sleep

update_hdparm.sh

#!/bin/sh
#Updates /etc/hdparm.conf to prevent spindown of disks

file=/etc/hdparm.conf

cmd=$1

add_disk()
{
  echo "$1 {" >> $file
  echo "  apm = 255" >> $file
  echo "  spindown_time = 0" >> $file
  echo "}" >> $file

}

set_disk()
{
  hdparm -S 0 -B 255 $1
}

usage()
{
  echo "$0"
  echo "    -set    sets all ata drives to never sleep direcly via hdparm"
  echo "    -add    adds all ata drives to the $file so hdparm will set values on next boot"
}

if [ "$#" -eq "0" ]
then
  usage
  exit
fi

for disk in `ls /dev/disk/by-id/ata*`
do
  echo $disk | grep "\-part[0-9]" > /dev/null 2>&1
  if [ "$?" -ne "0" ]; then
    if [ "$cmd" = "-set" ]; then
      echo "Updating $disk"
      set_disk $disk
    else
      echo "Adding $disk to $file"
      add_disk $disk
    fi
  fi
done