Export has multiple meanings in Oracle. The actual Export utility will only export binary files that oracle can read to import back into a database. However you can use sqlplus and concatentation operators to export to an ascii text file.
Warning watch out for columns with embedded commas in data like a name field example.
sqlplus -s /nolog
set heading off;
set pagesize 0;
set feedback off;
set echo off;
set pause off;
set termout off;
select col1||','||col2||','||col3 from tableA;
the file /tmp/comma.out now contains your comma delimeted ascii text file.