Admittedly, I did not realize the benefit at first until there came a need.
Example:
# Set ORACLE_SID
ORACLE_SID=$1
export ORACLE_SID
### This retrieve the numeric value from PROD1/PROD2, i.e. 1,2 respectively
n=`echo "${ORACLE_SID:(-1)}"`
run {
backup tag 'ARCHIVED_LOG' archivelog all delete input skip inaccessible;
alter database backup controlfile to trace as '/rman_bkup$n/$ORACLE_SID/cf_@.sql' REUSE RESETLOGS;
create pfile='/rman_bkup$n/$ORACLE_SID/init@.ora' from spfile;
create pfile from spfile;
}
