spooling out table definitions (structure) from sqlplus

Pls how can i spool out table definitions/structure from the database via sqlplus.

spool table.txt
desc table_name
spool off

Here's a DBMS_METADATA sample ...

Code:

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Set Long 100000 Pagesize 0
Execute DBMS_Metadata.Set_Transform_Param(Dbms_Metadata.Session_Transform,'STORAGE',False);
Select  DBMS_Metadata.Get_DDL('TABLE',table_name) From user_tables;
Select  DBMS_Metadata.Get_DDL('INDEX',index_name) From User_Indexes;

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thanx