reverted brackets and fixed grep

ubiquiti_stock.sh

@@ -7,9 +7,9 @@ SOURCE_FILE='/tmp/source.html'
 
 wget -qO ${SOURCE_FILE} ${URL}
 
-INVENTORY_QUANTITY=$(grep -o '"inventory_quantity":.,' ${SOURCE_FILE} | grep -o '[0-9]\+')
+INVENTORY_QUANTITY=$(grep -o -m 1 '"inventory_quantity":[0-9]\+,' ${SOURCE_FILE} | grep -o '[0-9]\+')
 
-if [ ${INVENTORY_QUANTITY} -gt 0 ]; then
+if [[ ${INVENTORY_QUANTITY} -gt 0 ]]; then
     MESSAGE="There are currently ${INVENTORY_QUANTITY} in stock. ${URL}"
     echo ${MESSAGE}
 fi