$ export ORACLE_SID=orcl
$ echo $ORACLE_SID
$ sqlplus / as sysdba
SQL> select instance_name from v$instance;

$ sqlplus sys/oracle@rcat as sysdba
SQL> select instance_name from v$instance;

create tablespace rcat_ts
datafile '/u01/app/oracle/oradata/rcat/rcat01.dbf'
size 30m;

$ cat ts.sql
create tablespace rcat_ts
datafile '/u01/app/oracle/oradata/rcat/rcat01.dbf'
size 30m;

$ sqlplus sys/oracle@rcat as sysdba @ts.sql

$ sqlplus sys/oracle@rcat as sysdba 
SQL> @ts.sql

create user rcatowner identified by oracle
temporary tablespace temp
default tablespace rcat_ts
quota unlimited on rcat_ts;

grant recovery_catalog_owner to rcatowner;

$ sqlplus sys/oracle@rcat as sysdba @user.sql

$ sqlplus sys/oracle@rcat as sysdba 
SQL> @user.sql

$ rman target / catalog rcatowner/oracle@rcat
RMAN> create catalog;