raspberry pi fan control

#!/bin/sh
timestamp() {
date +"%Y-%m-%d %T"
}
LOGDIR="/var/log/fan.log"

VALUE=55

TEMP=`/opt/vc/bin/vcgencmd measure_temp | cut -c6,7`
STATUS=`cat /sys/class/gpio/gpio2/value`

if [ -z "${STATUS}" ]; then
	echo "2">/sys/class/gpio/export
	echo "out">/sys/class/gpio/gpio2/direction
fi

#######echo `timestamp` " Info: Temperature: $TEMP">>$LOGDIR
if [ $TEMP -ge $VALUE ] && [ $STATUS -eq 0 ]
then
#######echo `timestamp` " Warning: Fan started.">>$LOGDIR
echo "1">/sys/class/gpio/gpio2/value
elif [ $TEMP -le $VALUE ] && [ $STATUS -eq 1 ]
then
#######echo `timestamp` " Warning: Fan stopped.">>$LOGDIR
echo "0">/sys/class/gpio/gpio2/value
fi