How to correct text form SQL Prompt in anonymous block

How to correct text form SQL Prompt in anonymous block

Example: In below PL/SQL block i've user invalid identifier "timestamp"

SQL> declare
v_date timestamp;
begin
select timestamp - 1/24 into v_date from dual;
dbms_output.put_line('one hour ago: '||v_date);
end;
/  2    3    4    5    6    7
select timestamp - 1/24 into v_date from dual;
       *
ERROR at line 4:
ORA-06550: line 4, column 8:
PL/SQL: ORA-00904: "TIMESTAMP": invalid identifier
ORA-06550: line 4, column 1:
PL/SQL: SQL Statement ignored


SQL> c /timestamp/systimestamp -- correcting spelling.
  4* select systimestamp - 1/24 into v_date from dual;

# Again we've executed, now its working

SQL> /
one hour ago: 26-NOV-14 05.50.37.000000 PM

PL/SQL procedure successfully completed.

SQL>
SQL>