Check Trim script

#!/bin/bash
#
if [ $# -ne 3 ]; then
echo
echo "Usage: $0 "
echo
echo " is a temporary file for the test"
echo " is the file size in MB"
echo " is the device being tested, e.g. /dev/sda"
echo
echo "Example: $0 tempfile 5 /dev/sda"
echo
echo "This would run the test for /dev/sda creating a"
echo "temporary file named \"tempfile\" with 5 MB"
echo
exit 1
fi
FILE="$1"
SIZE=$2
DEVICE="$3"
# Create the temporary file
dd if=/dev/urandom of="$FILE" count=1 bs=${SIZE}M oflag=direct
sync
# Get the address of the first sector
hdparm --fibmap "$FILE"
SECTOR=`hdparm --fibmap "$FILE" | tail -n1 | awk '{ print $2; }'`
# Read the first sector prior to deletion
hdparm --read-sector $SECTOR "$DEVICE"
echo
echo "This is a sector of the file. It should have been successfully read"
echo "and show a bunch of random data."
echo
read -n 1 -p "Press any key to continue..."
# Delete the file and re-read the sector
rm -f $FILE
sync
echo
echo "File deleted. Sleeping for 120 seconds before re-reading the sector."
echo "If TRIM is working, you should see all 0s now."
sleep 5
hdparm --read-sector $SECTOR "$DEVICE"
echo
echo "If the sector isn't filled with 0s, something is wrong with your"
echo "configuration. Try googling for \"TRIM SSD Linux\"."
echo
exit 0