Sample RMAN backup

connect target /

RUN
{
  ALLOCATE CHANNEL disk1 DEVICE TYPE DISK FORMAT '/oradata/backup/backup_%T_%u_%s_%p' MAXPIECESIZE 2G;
  BACKUP DATABASE PLUS ARCHIVELOG;
  crosscheck archivelog all;
  delete noprompt expired archivelog all;
}

connect target /
Connect to the Default RMAN database

RUN
{
//command
}

To start RMAN command


ALLOCATE CHANNEL disk1 DEVICE TYPE DISK FORMAT '/oradata/backup/backup_%T_%u_%s_%p' MAXPIECESIZE 2G; 
Specify the backup location and the RMAN backup file format
Indicate that the max size of each backup file is 2Gb.


BACKUP DATABASE PLUS ARCHIVELOG;
backup the database datafile and archivelog


crosscheck archivelog all;
delete noprompt expired archivelog all;
Check archivelog  and delete the expired archivelog