How to save a value in a bind variable

Useful for tracing or explaining queries that use bind variables:

connect scott/tiger
var leom char(10);
var eod char(10);

exec :leom := to_date('30.09.2013','DD.MM.YYYY');
exec  :eod := to_date('31.10.2013','DD.MM.YYYY');

SELECT col1, col2 ....col n
FROM   TABLE1
WHERE  START_DATE <= :eod
AND    END_DATE   <= :leom;