define s=&1

REM TRUNCATE IMPORTED TABLES

DECLARE
  procedure truncate_table (l_table IN varchar2) is
    csr NUMBER;
    table_does_not_exist EXCEPTION;
    PRAGMA EXCEPTION_INIT(table_does_not_exist, -00942);
  begin 
    csr := DBMS_SQL.OPEN_CURSOR;
    DBMS_SQL.PARSE(csr,'truncate table '||l_table, DBMS_SQL.V7);
    DBMS_SQL.CLOSE_CURSOR(csr); 
  exception
    when table_does_not_exist then
       null;
    when others then
      DBMS_OUTPUT.PUT_LINE ('Error: '||sqlerrm);
      DBMS_SQL.CLOSE_CURSOR(csr); 
  end;

BEGIN
  dbms_output.enable(16000); 
  truncate_table('&s');
END;
/
