Usually you just grep the log file. You can also check the return code from sqlldr.
#!/usr/bin/ksh
sqlldr ...
RETVAL=$?
# +-------+-------+------------+
# | UNIX |Windows| VMS |
# +----------------------------+-------+-------+------------+
# | Successful | 0 | 0 | 1 |
# | Unrecoverable failure | 1 | 3 | %X10000002 |
# | At least one row rejected | 2 | 2 | 2 |
# | O/S Errors | 3 | 4 | 3 |
# +----------------------------+-------+-------+------------+
if [ $RETVAL -eq 2 ]; then
exit 0;
else
exit $RETVAL;
fi