I used these 2 lines to make aliases for all my datafiles, then rename them to the alias..
This helped with a smoother RMAN active database duplicate. Otherwise it can get confused
set linesize 160
set pagesize 0
select 'alter diskgroup DATA add alias ''' || substr(name,1,instr(name,'.')) || 'dbf'' for ''' || name || ''';' from v$datafile;
set linesize 160
set pagesize 0
select 'alter database rename file '''|| name || ''' to ''' || substr(name,1,instr(name,'.')) || 'dbf'';' from v$datafile;