Before calling RMAN, it may be useful to set the NLS_DATE_FORMAT NLS_LANG and environment variables. These variables determine the format for the time parameters in RMAN commands such as used Restore, Recover and Report.
NLS_DATE_FORMAT=’Mon DD YYYY HH24:MI:SS’
A database is not mounted assumes the default character set that is US7ASCII. If your character set is different from the default, then RMAN returns errors after the database is installed. For example, if the character set WE8DEC, you can set the NLS_LANG parameter as follows:
You also have to use “NLS_LANG” and “NLS_DATE_FORMAT” for using “NLS_DATE_FORMAT”.