[oracle@emrepos ~]$ unset ORACLE_HOME
[oracle@emrepos ~]$ unset ORACLE_SID
[oracle@ ~]$ export PATH=$BASE_PATH


[oracle@ ~]$ /u01/app/oracle/product/em13c/middleware/bin/emctl stop oms -all
Oracle Enterprise Manager Cloud Control 13c Release 3
Copyright (c) 1996, 2018 Oracle Corporation.  All rights reserved.
Stopping Oracle Management Server...
WebTier Successfully Stopped
Oracle Management Server Successfully Stopped
Oracle Management Server is Down
JVMD Engine is Down
Stopping BI Publisher Server...
BI Publisher Server Successfully Stopped
AdminServer Successfully Stopped
BI Publisher Server is Down

[oracle@ ~]$ /u01/app/oracle/product/em13c/agentbase/agent_13.3.0.0.0/bin/emctl stop agent
Oracle Enterprise Manager Cloud Control 13c Release 3
Copyright (c) 1996, 2018 Oracle Corporation.  All rights reserved.
Stopping agent ... stopped.

[oracle@ ~]$ export ORACLE_HOME=$ORACLE_BASE/product/18.3.0/db_1
[oracle@ ~]$ export ORACLE_SID=emrepos
[oracle@orcl ~]$ export PATH=$ORACLE_HOME/bin:$ORACLE_HOME/OPatch::$BASE_PATH
 
[oracle@orcl ~]$ sqlplus / as sysdba

SQL*Plus: Release 18.0.0.0.0 - Production on Tue Oct 9 01:31:28 2018
Version 18.3.0.0.0

Copyright (c) 1982, 2018, Oracle.  All rights reserved.


Connected to:
Oracle Database 18c Enterprise Edition Release 18.0.0.0.0 - Production
Version 18.3.0.0.0

SQL> shutdown immediate;
Database closed.
Database dismounted.
ORACLE instance shut down.
 
SQL> exit
Disconnected from Oracle Database 18c Enterprise Edition Release 18.0.0.0.0 - Production
Version 18.3.0.0.0

[oracle@orcl ~]$ lsnrctl stop

LSNRCTL for Linux: Version 18.0.0.0.0 - Production on 09-OCT-2018 01:32:53

Copyright (c) 1991, 2018, Oracle.  All rights reserved.

Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST=emcc)(PORT=1521)))
The command completed successfully

[oracle@ ~]$ export ORACLE_HOME=$ORACLE_BASE/product/18.3.0/db_1
[oracle@ ~]$ export ORACLE_SID=emrepos
[oracle@emrepos ~]$ export PATH=$ORACLE_HOME/bin:$ORACLE_HOME/OPatch::$BASE_PATH

[oracle@emrepos ~]$ sqlplus / as sysdba

SQL*Plus: Release 18.0.0.0.0 - Production on Fri Oct 12 08:31:26 2018
Version 18.3.0.0.0

Copyright (c) 1982, 2018, Oracle.  All rights reserved.

Connected to an idle instance.

SQL> startup
ORACLE instance started.

Total System Global Area 3003120840 bytes
Fixed Size                  8662216 bytes
Variable Size             771751936 bytes
Database Buffers         2214592512 bytes
Redo Buffers                8114176 bytes
Database mounted.
Database opened.

SQL> exit
Disconnected from Oracle Database 18c Enterprise Edition Release 18.0.0.0.0 - Production
Version 18.3.0.0.0

[oracle@emrepos ~]$ lsnrctl start

LSNRCTL for Linux: Version 18.0.0.0.0 - Production on 12-OCT-2018 08:32:16

Copyright (c) 1991, 2018, Oracle.  All rights reserved.

Starting /u01/app/oracle/product/18.3.0/db_1/bin/tnslsnr: please wait...

TNSLSNR for Linux: Version 18.0.0.0.0 - Production
System parameter file is /u01/app/oracle/product/18.3.0/db_1/network/admin/listener.ora
Log messages written to /u01/app/oracle/diag/tnslsnr/emcc/listener/alert/log.xml
Listening on: (DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=emcc.localdomain)(PORT=1521)))
Listening on: (DESCRIPTION=(ADDRESS=(PROTOCOL=ipc)(KEY=EXTPROC1521)))

Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST=emcc.localdomain)(PORT=1521)))
STATUS of the LISTENER
------------------------
Alias                     LISTENER
Version                   TNSLSNR for Linux: Version 18.0.0.0.0 - Production
Start Date                12-OCT-2018 08:32:16
Uptime                    0 days 0 hr. 0 min. 0 sec
Trace Level               off
Security                  ON: Local OS Authentication
SNMP                      OFF
Listener Parameter File   /u01/app/oracle/product/18.3.0/db_1/network/admin/listener.ora
Listener Log File         /u01/app/oracle/diag/tnslsnr/emcc/listener/alert/log.xml
Listening Endpoints Summary...
  (DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=emcc.localdomain)(PORT=1521)))
  (DESCRIPTION=(ADDRESS=(PROTOCOL=ipc)(KEY=EXTPROC1521)))
The listener supports no services
The command completed successfully

[oracle@emrepos ~]$ unset ORACLE_HOME
[oracle@emrepos ~]$ unset ORACLE_SID
[oracle@ ~]$ export PATH=$BASE_PATH

[oracle@ ~]$ /u01/app/oracle/product/em13c/middleware/bin/emctl start oms
Oracle Enterprise Manager Cloud Control 13c Release 3
Copyright (c) 1996, 2018 Oracle Corporation.  All rights reserved.
Starting Oracle Management Server...
WebTier Successfully Started
Oracle Management Server Successfully Started
Oracle Management Server is Up
JVMD Engine is Up
Starting BI Publisher Server ...
BI Publisher Server Successfully Started
BI Publisher Server is Up

[oracle@ ~]$ /u01/app/oracle/product/em13c/agentbase/agent_13.3.0.0.0/bin/emctl start agent
Oracle Enterprise Manager Cloud Control 13c Release 3
Copyright (c) 1996, 2018 Oracle Corporation.  All rights reserved.
Agent is already running