RMAN command enables logging or spooling for backup in Oracle

Enable logging during the RMAN command line:

A log parameter is used to define or write in a log file.

rman TARGET / LOG = E:\rman\rman_log.log 

rman TARGET / cmdfile=E:\rman\cmd_file.txt LOG = E:\rman\rman_log.log

-- Mention append to append the file:
rman TARGET / cmdfile=E:\rman\cmd_file.txt LOG = E:\rman\rman_log.log append

Spooling the log file in the command file or direct command RMAN prompt:

rman> spool log to E:\rman\rman_log.log;
rman> run {execute script.................}
rman> spool log off;