Disable and later enable all table indexes in Oracle

DECLARE
  CURSOR  usr_idxs IS select * from user_indexes;
  cur_idx  usr_idxs% ROWTYPE;
  v_sql  VARCHAR2(1024);

BEGIN
  OPEN usr_idxs;
  LOOP
    FETCH usr_idxs INTO cur_idx;
    EXIT WHEN NOT usr_idxs%FOUND;

    v_sql:= 'ALTER INDEX ' || cur_idx.index_name || ' UNUSABLE';
    EXECUTE IMMEDIATE v_sql;
  END LOOP;
  CLOSE usr_idxs;
END;

select dbms_metadata.get_ddl('INDEX', u.index_name) from user_indexes u;

alter session set skip_unusable_indexes = true;
select 'alter index ' || u.index_name || ' unusable;' from user_indexes u;

select 'alter index ' || u.index_name || ' rebuild online;' from user_indexes u;

set pagesize 0

alter session set skip_unusable_indexes = true;
spool c:tempdisable_indexes.sql
select 'alter index ' || u.index_name || ' unusable;' from user_indexes u;
spool off
@c:tempdisable_indexes.sql

select 'alter index ' || u.index_name ||
' rebuild online;' from user_indexes u;