Just an update, did not see the note, but you can try this
1.- connect and start in mount mode only
sqlplus / as sysdba
shutdown immediate
startup mount
set linesize 1024
set pagesize 0
2.- Generates mv for os commands
spool /tmp/script_rename.sh
select '! mv '||name||' '||name||'_'||file# from v$datafile;
spool off
3.-Generates alter database rename files
spool /tmp/script_rename.sql
select 'alter database rename file '''||name||''' TO '''||name||'_'||file#||''' ;' from v$datafile;
spool off
4.- Edit, adatpt & run /tmp/script_rename.sh - just remove unwanted lines
5.- Edit adapt & run /tmp/script_rename.sql - just remove unwanted lines
Actually this thread helped me quite a lot yesterday,