imac fan out of control 2

Hello all,

I found this brilliant script on here (on an older thread) to solve the issue in the absence of the SSD fan control application for Linux :-

smartfancontrol.sh

#### enter your preferred values here ##################
speed_min=1100 #RPM
speed_max=1200 #RPM
temp_min=46 #degrees celsius
temp_max=60 #degrees celsius

########## Do not edit below this line ###################

echo 1 > /sys/devices/platform/applesmc.768/fan2_manual

while [ 1 ]
do

temp=$(/usr/sbin/smartctl -A /dev/sda | grep ^194 | awk '{print $10}')

if [[ $temp -lt $temp_min ]]; then
speed=$speed_min
elif [[ $temp -gt $temp_max ]]; then
speed=$speed_max
else
x=$(($speed_max-$speed_min))
y=$(($(($temp-$temp_min))*100))
z=$(($(($temp_max-$temp_min))*100))
a=$(($x*$y/$z))
speed=$(($a+$speed_min))
fi

echo $speed >/sys/devices/platform/applesmc.768/fan2_output

printf '[ %i C | %i rpm ]\n' $temp $speed

sleep 60
done

I would like to run this script at start up automatically and it needs root privileges to run. I've looked at a few ways to do this but all are rather confusing. Would someone be kind enough to tell me how to get this to run automatically at start up please?