shell script to monitor ASM DG space to send alert

Script to monitor ASM DG space. it will send alert if space is reached to 90% full and also if its full 80% with less than 100 GB space. schedule it to run for every 15min

-->  90% full --- send alert
-->  80% and avail space less than 100GB -- send alert


#!/bin/bash
export ORACLE_SID=`egrep -i ":Y|:N" /etc/oratab | cut -d":" -f1 | grep -v "\#" | grep -v "\*"|grep ASM`
if [ -z "$ORACLE_SID" ]
then
exit;
else
export ORACLE_HOME=`egrep -i ":Y|:N" /etc/oratab |grep $ORACLE_SID| cut -d":" -f2 | grep -v "\#" | grep -v "\*"`
export PATH=$ORACLE_HOME/bin:/usr/sbin:$PATH
DG_LIST=`sqlplus -s "/ as sysdba" <<EOF
       set heading off feedback off verify off
       SELECT name from v\\$asm_diskgroup ORDER BY name;
       exit
EOF`
for i in $DG_LIST; do
DG_SPACE=`sqlplus -s "/ as sysdba" <<EOF
       set heading off feedback off verify off
       SELECT name  group_name,total_mb/1024,ROUND((free_mb)/1024) Avail_GB,ROUND((1- (free_mb / total_mb))*100)  pct_used FROM v\\$asm_diskgroup where name='$i';
       exit
EOF`
DG_NAME="`echo $DG_SPACE|awk '{ print $1}'`"
PCT="`echo $DG_SPACE|awk '{ print $4}'`"
AVL_GB="`echo $DG_SPACE|awk '{ print $3}'`"
if [  $PCT -ge 80 ] && [ $PCT -lt 90 ] 
then 
 if [ $AVL_GB -lt 100 ]
 then 
 echo `hostname`  $DG_SPACE | mail -r "sender@company.com" -s "`hostname`:GOLD-oracle ASM-DG $DG_NAME utilization in critical" "yourmail@company.com"
 fi
 else if [ $PCT -ge 90 ]
 then
 echo `hostname`  $DG_SPACE | mail -r "sender@company.com" -s "`hostname`:GOLD-oracle ASM-DG $DG_NAME  utilization in critical" "yourmail@company.com"
 fi
 fi
done
fi