sergey@sergey-Bionic:~$ sqlplus SYS/Mail2sergei as SYSDBA

SQL*Plus: Release 18.0.0.0.0 - Production on Mon Apr 22 12:42:34 2019
Version 18.3.0.0.0

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

ERROR:
ORA-12547: TNS:lost contact


Enter user-name:

nano .bashrc

#ORACLE
export ORACLE_HOME=/u01/app/PROD/product/18c
export ORACLE_SID=XE
export ORACLE_BASE=/u01/app/PROD
export LD_LIBRARY_PATH=$ORACLE_HOME/lib:$LD_LIBRARY_PATH
export PATH=$ORACLE_HOME/bin:$PATH
#ORACLE

sergey@sergey-Bionic:~$ nano /u01/app/PROD/product/18c/network/admin/tnsnames.ora
# tnsnames.ora Network Configuration File: /home/sergey/Downloads/ORACLE_10/network/admin/tnsnames.ora
# Generated by Oracle configuration tools.

LISTENER_ORCL =
  (ADDRESS = (PROTOCOL = TCP)(HOST = sergey-Bionic)(PORT = 1522))


sergey@sergey-Bionic:~$ nano /u01/app/PROD/product/18c/network/admin/listener.ora

# listener.ora Network Configuration File: /home/sergey/Downloads/ORACLE_10/network/admin/listener.ora
# Generated by Oracle configuration tools.

LISTENER =
  (DESCRIPTION_LIST =
    (DESCRIPTION =
      (ADDRESS = (PROTOCOL = TCP)(HOST = sergey-Bionic)(PORT = 1522))
      (ADDRESS = (PROTOCOL = IPC)(KEY = EXTPROC1522))
    )
  )

sergey@sergey-Bionic:~$ nano /u01/app/PROD/product/18c/network/admin/sqlnet.ora

# sqlnet.ora Network Configuration File: /home/sergey/Downloads/ORACLE_10/network/admin/sqlnet.ora
# Generated by Oracle configuration tools.

NAMES.DIRECTORY_PATH= (TNSNAMES, EZCONNECT)


oracle@sergey-Bionic:~$ lsnrctl start

LSNRCTL for Linux: Version 18.0.0.0.0 - Production on 22-APR-2019 13:05:13

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

Starting /u01/app/PROD/product/18c/bin/tnslsnr: please wait...

TNSLSNR for Linux: Version 18.0.0.0.0 - Production
Log messages written to /u01/app/PROD/diag/tnslsnr/sergey-Bionic/listener/alert/log.xml
Listening on: (DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=sergey-Bionic)(PORT=1521)))

Connecting to (ADDRESS=(PROTOCOL=tcp)(HOST=)(PORT=1521))
STATUS of the LISTENER
------------------------
Alias                     LISTENER
Version                   TNSLSNR for Linux: Version 18.0.0.0.0 - Production
Start Date                22-APR-2019 13:05:13
Uptime                    0 days 0 hr. 0 min. 0 sec
Trace Level               off
Security                  ON: Local OS Authentication
SNMP                      OFF
Listener Log File         /u01/app/PROD/diag/tnslsnr/sergey-Bionic/listener/alert/log.xml
Listening Endpoints Summary...
  (DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=sergey-Bionic)(PORT=1521)))
The listener supports no services
The command completed successfully
oracle@sergey-Bionic:~$