sqlplus 
$DB_ACCT << EOSQL
       set heading off
       set termout off
       set pagesize 0
       set linesize 35
       set feedback off
       set serveroutput off
              spool FILE.txt

              Select col_with_a||col_with_b||col_with_c from alphabet_table;
             
              spool off;
                
        exit;
EOSQL

bcm@bcm-laptop:~$ cat a.sql 
set term off echo off pages 0
spool a.lis
select a from t2;
spool off
exit
bcm@bcm-laptop:~$ sqlplus -s user1/user1 @a.sql
bcm@bcm-laptop:~$ cat a.lis
         1                                                                      
         2                                                                      
         3                                                                      
         4