Oracle Offline Database Backup/Restore (OS backup)

I did some tests. Here I backed up oracle and do some changes. Later I restored with copying files. You can just copy or use any backup software.

Backup
RMAN> connect target;
RMAN> shutdown immediate;
copy oracle datafiles to backup directory
#cp -R /oracle_datafiles_dir/* /backup_dir/
remove redolog files
#rm redo*.log /backdir

Break down your database
open database and do some changes
RMAN> startup;
shutdown database and delete datafiles
RMAN> shutdown immediate;
#rm /oracle_datafiles_dir/*.dbf

Restore
Move backup files to original directory
#cp -R /backup_dir/* /oracle_datafiles_dir/
start database
RMAN> startup mount;
RMAN> recover database until cancel;
RMAN> alter database open resetlogs;

You do not have to do last two steps if you backup redo logs and restore it.