I would suggest that you use a query to build a your cold backup script to get the paths to all your datafiles, control files, and redologs. This would eliminate the need for to know where you files resides because their locations would be gotten from the database. Also if you hardcode your paths every time you add a data file or redologs or move files around you would have to modify your backup script. The oracle scripts section of the site offers some excellent examples. Here the link to the scripts section: http://www.dbasupport.com/oracle/scripts/.
If you would like a copy of the script that I use on my Solaris system send me an email at [email protected].