Oracle: Tablespace critical threshold message

A DBA's main responsibility also include checking the tablespace space regularly,We can check this space each time with help of some useful views like dba_data_files provided by oracle.But this is tough some time whenever some developer load the data and suddenly you see the space almost occupied.So I decided to use the below script which will send me the alert mail whenever the space becomes 85% filled(critical threshold) which will be very much helpful to make sure the tablespace is having enough space. 

The script is as given below: 

Tablespace critical message when it becomes 85% occupied:
---------------------------------------------------------- 

#!/bin/ksh 

export PATH=/star/app/oracle/product/11.1.0/db_1/bin:/usr/sbin:/usr/kerberos/bin:/usr/local/bin:/bin:/usr/bin:/home/star/bin 
export ORACLE_BASE=/star/app/oracle 
export LD_LIBRARY_PATH=/star/app/oracle/product/11.1.0/db_1/lib:/lib:/usr/lib 
export LD_LIBRARY_PATH=/ora11g/app/oracle/product/11.1.0.7/lib:/usr/lib:/usr/ccs/bin:/usr/dt/lib 
export ORACLE_HOME=/star/app/oracle/product/11.1.0/db_1 


MAILLIST=`cat /home/star/scripts/email.lst` 
LOGFILE=/tmp/chk_ts_$1.log 

echo $1 

CHKUP=`ps -ef | grep pmon | grep $1 | wc -l` 

if [ "${CHKUP}" -eq 1 ] 
then 
echo "The Pmon Process is running on host" 
else 
echo " ****************************************************************" >> $LOGFILE 
echo " " `date` " Pmon Proces is not found" >> $LOGFILE 
echo " ****************************************************************" >> $LOGFILE 
exit 0 
fi 

export ORACLE_SID=$1 

sqlplus -s "/ as sysdba" <WHENEVER SQLERROR EXIT SQL.SQLCODE
set echo off
set trimspool on
set trimout on
set verify off
set feedback off
column TABLESPACE_NAME format a18
column "%ocup" format a6
set lines 200
spool /tmp/chk_ts_$1.spl
SELECT total.tablespace_name tablespace_name,
ROUND (tot / 1024 / 1024) total,
ROUND ((tot - tot_l) / 1024 / 1024) occupied,
ROUND (tot_l / 1024 / 1024) remain,
ROUND (max_l / 1024 / 1024) max_extent,
ROUND ((tot - tot_l) * 100 / tot) || '%' AS "%ocup"
FROM (SELECT tablespace_name, SUM (BYTES) tot_l, MAX (BYTES) max_l
FROM dba_free_space
GROUP BY tablespace_name
UNION
SELECT d.tablespace_name,
f.bytes_free + f.bytes_used - NVL (p.bytes_used, 0) tot_l,
0 max_l
FROM SYS.v_\$temp_space_header f,
dba_temp_files d,
SYS.v_\$temp_extent_pool p
WHERE f.tablespace_name(+) = d.tablespace_name AND f.file_id(+) = d.file_id
AND p.file_id(+) = d.file_id) libre,
(SELECT tablespace_name, SUM (BYTES) tot
FROM dba_data_files
GROUP BY tablespace_name
UNION
(SELECT tablespace_name, SUM (BYTES) tot
FROM dba_temp_files
GROUP BY tablespace_name)) total,
dba_tablespaces dba_t
WHERE total.tablespace_name = libre.tablespace_name(+)
AND total.tablespace_name = dba_t.tablespace_name
AND ROUND (tot_l / 1024 / 1024) < 1024
AND ROUND ((tot - tot_l) * 100 / tot) > 85
AND dba_t.tablespace_name NOT IN ('RBS')
ORDER BY ROUND ((tot - tot_l) * 100 / tot) DESC;
spo off
EOF
if [ -s /tmp/chk_ts_$1.spl ]; then
cat /tmp/chk_ts_$1.spl | mailx -s "Critical : ($1 on machinename.abcd.com.sg) Missing free space on tablespace of the database $1 -- Immediate Action" $MAILLIST
echo "---------------------------------------------------------------------------" >> $LOGFILE
echo `date` >> $LOGFILE
cat /tmp/chk_ts_$1.spl >> $LOGFILE
echo "---------------------------------------------------------------------------" >> $LOGFILE
rm -fr /tmp/chk_ts_$1.spl
fi