Spool file creation sometimes fails ??

Question

wks_srce_sys.unl file is being created by cow_estgen.sql
My problem is that when i run the application if wks_srce_sys.unl file is created successfully
the application runs successfully.other times when wks_srce_sys.unl file is not created and application fails.
and the application exits
system is logging into oracle successfully and estgen.sql is present in the said path
i have also given path to this file wks_srce_sys.unl but it has no effect
What can the problem be??
when i run this script in the shell prompt the file wks_srce_sys.unl is created successfully.
sqlplus -s $USERNM/$PASSWRD @$SPOOL_DIR/estgen.sql wks_srce_sys.unl
sqlplus -s $USERNM/$PASSWRD @$SPOOL_DIR/estgen.sql wks_srce_sys.unl
if [ ! -s wks_srce_sys.unl ]
then
echo "No Data available for validation" >> ${LOG}
exit 1
fi
===============
estgen.sql is:
===============
set pagesize 0
spool &1
select distinct(work_source_system) from est_generates;
set pagesize 1
exit

Answer 1

I'm not sure whether I've understood your problem exactly.
if [ ! -s wks_srce_sys.unl ]
then
echo "No Data available for validation" >> ${LOG}
exit 1
fi
Your code logic says EXIT if "wks_srce_sys.unl " file doesn't exist.And you say its hapening so.So,what's wrong?
Regards,
Bhagat