export ADFOLDER="//SERVER/FOLDER"

if grep -qs '/mnt/folderwin' /proc/mounts; then
    echo "It's mounted.";
else
    echo "It's not mounted.";
    mkdir -p /mnt/folderwin
    mount -t cifs -o "username=$ADUSER,password=$ADPASS,domain=$ADDOMAIN" $ADFOLDER /mnt/folderwin
fi