Installing Oracle 18c XE fails on fresh install of Oracle Linux 7.6 UEK5

[jesusmorenodiaz]

Running transaction
Installing : file-5.11-35.el7.x86_64 1/2
su: System error
[SEVERE] The su command is not configured properly or the oracle user does not have the required privileges to install the Oracle database. If you are running in a Docker environment, ensure to set the environment variable ORACLE_DOCKER_INSTALL=true and try again.
error: %pre(oracle-database-xe-18c-1.0-1.x86_64) scriptlet failed, exit status 1
Error in PREIN scriptlet in rpm package oracle-database-xe-18c-1.0-1.x86_64
Verifying : file-5.11-35.el7.x86_64 1/2
Verifying : oracle-database-xe-18c-1.0-1.x86_64 2/2

[jesusmorenodiaz]

It is same that issue #15.