enable/disable archive log in oracle 10g/11g

Enable
----------
SQL> archive log list
SQL> shutdown immediate
SQL> startup mount
SQL> alter database archivelog;
SQL> alter database open;
SQL> archive log list


Disable
----------
SQL> archive log list;
SQL> shutdown immediate
SQL> startup mount
SQL> alter database noarchivelog;
SQL> alter database open;
SQL> archive log list;