echo Select a backup from the following:
bkupset=''
OLDIFS="$IFS"
IFS="
"
PS3='Select backup: '
echo "   DBID     |TAG                    |START_TIME          |KEEP_UNTIL"
while [[ $bkupset = "" ]]; do
  select bkupset in $(sqlplus -s $rmanuser/$rmanpw@rmcat <<EOF
              set echo off feedback off verify off head off trimsp on
              alter session set nls_date_format='dd-Mon-yyyy_hh24:mi:ss';
              select d.dbid,
                      bp.tag,
                      min(bp.start_time),
                      min(bs.keep_until)
               from rc_backup_piece bp
               join rc_database d
                 on bp.db_key=d.db_key
               join rc_backup_set bs
                 on bp.bs_key=bs.bs_key
               where d.name=upper('$ORACLE_SID')
                 and bs.keep='YES'
               group by d.dbid,
                        bp.tag,
                        bs.keep_until
               order by d.dbid,
                        bp.tag
               ;
EOF
) "None of the above" ; do
  if [[ $bkupset = "" ]]; then
     echo
     echo "Please enter a valid number. Retry.";
     echo
  elif [[ $bkupset = "None of the above" ]]; then
     exit ;
  else {
        break ;
       }
  fi
  break
  done
done
#
unset PS3
IFS="$OLDIFS"

Select a backup from the following:
   DBID     |TAG                    |START_TIME          |KEEP_UNTIL
1)  528959692 MYDB_20170228_104831       28-Feb-2017_10:49:11
2) 31-Mar-2017_00:00:00
3)  528960845 MYDB_20170228_105831       28-Feb-2017_10:59:14
4) 15-Mar-2017_00:00:00
5) None of the above
Select backup: 5

131 IFS="
132 "