ARRAY=(/ /boot /var /usr) # fstab
ARRAY2=(/ /xboot /var) # df
max=${#ARRAY[@]}
max2=${#ARRAY2[@]}
if [ $max -ne $max2 ]
then
  echo "different no of elements, let's find out"
  i=0 j=0
  while [ $i -lt $max ] || [ $j -lt $max2 ]
  do
    if [[ "${ARRAY[$i]}" != "${ARRAY2[$j]}" ]]
    then
      if [[ "${ARRAY[$i]}" = "${ARRAY2[$((j+1))]}" ]]
      then
        echo "df ${ARRAY2[$j]} doesnt exist in fstab ${ARRAY[$i]}"
        j=$((j+1))
      elif [[ "${ARRAY[$((i+1))]}" = "${ARRAY2[$j]}" ]]
      then
        echo "fstab ${ARRAY[$i]} doesnt exist in df ${ARRAY2[$j]}"
        i=$((i+1))
      else
        echo "mismatch fstab ${ARRAY[$i]} and df ${ARRAY2[$j]}"
        i=$((i+1)) j=$((j+1))
      fi
    else
      i=$((i+1)) j=$((j+1))
    fi
  done
fi