umount_usb(){
    mnt=`df -h | grep /root/usb | wc -l`
    count=0
    while [ $mnt -eq 1 -a $count -le 5 ]
    do
	umount -f /root/usb/
	mnt=`df -h | grep /root/usb | wc -l`
	count=`expr $count + 1`
	sleep 1
	if [ $count -ge 5 ];then
	    exit
	fi
    done
}

umount_usb
echo -e "d\n1\nd\n2\nd\n3\nd\n4\n\nw" | fdisk /dev/sda
sleep 1
echo -e "n\np\n1\n1\n\nw" | fdisk /dev/sda
sleep 1
umount_usb
if [ $1 == "ext4" ];then
    echo -e "\ny" | mkfs.ext4 -T largefile /dev/sda1
    sleep 1
    mount -t ext4 /dev/sda1 /root/usb
else
    mkfs.vfat -F 32 /dev/sda1
    sleep 1
    mount -t vfat /dev/sda1 /root/usb
fi