oracle-startup-linux

First you have to startup the database "container" and just after , start the pluggable database as you need:

Env settings: (.bash_profile)

PATH=/usr/local/bin:/usr/bin:/usr/local/sbin:/usr/sbin:/opt/oracle/dba/.local/bin:/opt/oracle/dba/bin:/opt/oracle/dba/app/dba/product/12.1.0/dbhome_1/bin
ORACLE_SID=orcl
SID=orcl

ORACLE_HOME=/opt/oracle/dba/app/dba/product/12.1.0/dbhome_1/

lsnrctl start

[dba@soalinux ~]$ lsnrctl start

LSNRCTL for Linux: Version 12.1.0.2.0 - Production on 06-JUN-2018 09:56:16

Copyright (c) 1991, 2014, Oracle.  All rights reserved.

Starting /opt/oracle/dba/app/dba/product/12.1.0/dbhome_1//bin/tnslsnr: please wait...

TNSLSNR for Linux: Version 12.1.0.2.0 - Production
System parameter file is /opt/oracle/dba/app/dba/product/12.1.0/dbhome_1/network/admin/listener.ora
Log messages written to /opt/oracle/dba/app/dba/product/12.1.0/dbhome_1/log/diag/tnslsnr/soalinux/listener/alert/log.xml
Listening on: (DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=soalinux)(PORT=1521)))
Listening on: (DESCRIPTION=(ADDRESS=(PROTOCOL=ipc)(KEY=EXTPROC1522)))

Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST=soalinux)(PORT=1521)))
STATUS of the LISTENER
------------------------
Alias                     LISTENER
Version                   TNSLSNR for Linux: Version 12.1.0.2.0 - Production
Start Date                06-JUN-2018 09:56:17
Uptime                    0 days 0 hr. 0 min. 15 sec
Trace Level               off
Security                  ON: Local OS Authentication
SNMP                      OFF
Listener Parameter File   /opt/oracle/dba/app/dba/product/12.1.0/dbhome_1/network/admin/listener.ora
Listener Log File         /opt/oracle/dba/app/dba/product/12.1.0/dbhome_1/log/diag/tnslsnr/soalinux/listener/alert/log.xml
Listening Endpoints Summary...
  (DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=soalinux)(PORT=1521)))
  (DESCRIPTION=(ADDRESS=(PROTOCOL=ipc)(KEY=EXTPROC1522)))
The listener supports no services
The command completed successfully
[dba@soalinux ~]$

Connect to your database container and start it :

[dba@soalinux ~]$ sqlplus sys/oracle as sysdba

SQL*Plus: Release 12.1.0.2.0 Production on Wed Jun 6 09:58:59 2018

Copyright (c) 1982, 2014, Oracle.  All rights reserved.

Connected to an idle instance.

SQL> startup
ORACLE instance started.

Total System Global Area  838860800 bytes
Fixed Size                  2929936 bytes
Variable Size             570428144 bytes
Database Buffers          260046848 bytes
Redo Buffers                5455872 bytes
Database mounted.
Database opened.

Now you can check and start your pdbs:

SQL> show pdbs;

    CON_ID CON_NAME                       OPEN MODE  RESTRICTED
---------- ------------------------------ ---------- ----------
         2 PDB$SEED                       READ ONLY  NO
         3 PDBORCL                        MOUNTED
         4 PDBFMW                         MOUNTED
SQL> alter pluggable database all open;

Warning: PDB altered with errors.

SQL> show pdbs;

    CON_ID CON_NAME                       OPEN MODE  RESTRICTED
---------- ------------------------------ ---------- ----------
         2 PDB$SEED                       READ ONLY  NO
         3 PDBORCL                        READ WRITE YES
         4 PDBFMW                         READ WRITE NO