Note: You may also use DBMS_FILE_TRANSFER.COPY_FILE procedure to copy files. For doing that, you'd need to create 2 directory objects and copy the file. For example, to copy the above controlfile -
create directory D1 as '/home/pwprd/ravi';
create directory D2 as'+PWPRD_DATA/PWPRDDR/CONTROLFILE';
exec dbms_file_transfer.copy_file('D1','stby_PWPRD.ctl','D2', 'control01.ctl');