I'm trying to connect to the sql plus from ubuntu but I get this ERROR
ubuntu@ubuntu6:~$ su oracle
Contraseña:
oracle@ubuntu6:/home/ubuntu$ lsnrctl start
oracle@ubuntu6:/home/ubuntu$ sqlplus / as sysdba
SQL*Plus: Release 12.2.0.1.0 Production on Fri Jan 5 17:39:09 2018
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ERROR:
ORA-12547: TNS:lost contact