Below script will generate the DDLs of all the tablespaces in oracle.

SQL>set heading off;
SQL>set echo off;
SQL>Set pages 999;
SQL>set long 90000;
SQL>spool ddl_list.sql
SQL>select dbms_metadata.get_ddl('TABLESPACE',tb.tablespace_name) from dba_tablespaces tb;
SQL>spool off