#!/usr/bin/env bash

count_current=`df -hTP | grep -v Filesystem|awk '{print $1}'|wc -l`
echo "Currently mounted filesystems count is:"  $count_current
count_fstab=`cat /etc/fstab | grep -v '#'|awk '{print $1}'|wc -l`
echo "Total number of filesystems are:" $count_fstab
readonly differ=$(( count_current - count_fstab ))
if (( differ -eq  $((count_current - count_fstab)) ))
then
 echo "All filesystems are mounted correctly"

else
 echo "checking on it"
fi

[root@host ~]# ./script
Currently mounted filesystems count is: 10
Total number of filesystems are: 15
All filesystems are mounted correctly
[root@host ~]# umount /var/crash
[root@host ~]# ./script
Currently mounted filesystems count is: 9
Total number of filesystems are: 15
All filesystems are mounted correctly
[root@host ~]#