That is what you are doing with here document enclosed by <<EOF1 and EOF1. The back ticks return the output of the sqlplus command and
then, in your case, attempts to execute it.
If you want to capture the output of sqlplus in a variable or an array, then use the back ticks.
Code:
set -A RESULTS_ARRAY `sqlplus -s "user/pwd@service_name" <<EOF1
@xyz.sql
@pqr.sql
@abc.sql
EOF1`
for i in ${RESULTS_ARRAY[@]}
do
echo $i
done