Disk Cloner Script that uses dd to clone disks

diskclone.sh

#!/bin/bash
# https://asciinema.org/a/6LZefsbvLjgsuwQHOnQsBEaSj
IF=notset
OF=notset
BS=128M
CURDIR=$(dirname $(realpath -s $0))
SCRIPT=`basename "$0"`

if [[ ! -f /usr/bin/pv ]]; then
   echo "pv is not installed. Please install pv and try again"
   exit 1
fi

if [[ ! -f /usr/bin/whiptail ]]; then
   echo "whiptail is not installed. Please install newt and try again"
   exit 1
fi

if [[ $EUID -ne 0 ]]; then
   echo "This script must be run as root" 
   exit 1
fi

options=':i:o:b:'
while getopts $options option
do
    case $option in
        i) IF=$OPTARG;;
        o) OF=$OPTARG;;
	b) BS=$OPTARG;;
        *) echo "Unknown option"; exit;;
    esac
done

if [ "$IF" == "notset" ]; then
  echo "Input file is not set. Bailing out!"
  exit
fi

if [ "$OF" == "notset" ]; then
  echo "Output file is not set. Bailing out!"
  exit
fi


test_mount() {
  clear
  if [[ ! -d /tmp/test-mount ]]
  then
    mkdir /tmp/test-mount
  fi
  mount $OF /tmp/test-mount||exit 1
  whiptail --title "$SCRIPT" --msgbox "$OF Mounted!" 8 78
}

test_write() {
  touch /tmp/test-mount/.test
  if [[ -f /tmp/test-mount/.test ]]
  then
    whiptail --title "$SCRIPT" --msgbox "Successfully wrote file." 8 78
    test_umount
  else
    whiptail --title "$SCRIPT" --msgbox "Could not complete test write!" 8 78
    exit 1
  fi
}

test_umount() {
  rm /tmp/test-mount/.test
  umount /tmp/test-mount
  whiptail --title "$SCRIPT" --msgbox "Disk Image Unmounted." 8 78 
  whiptail --title "$SCRIPT" --msgbox "Disk Clone Validated." 8 78
  whiptail --title "$SCRIPT" --msgbox "Image created at $CURDIR/$OF" 8 78
}

(pv -n $IF | dd of=$OF bs=$BS conv=notrunc,noerror) 2>&1 | whiptail --gauge "Cloning $IF to $OF..." 10 70 0

if (whiptail --title "$SCRIPT" --yesno "Would you like to validate $OF" 8 78); then
  test_mount
  test_write
else
  whiptail --title "$SCRIPT" --msgbox "Image created at $CURDIR/$OF" 8 78
fi