This is usually XE for the free version. ORCL is another typical value.
After logging in, it can be determined from
select sys_context('USERENV','SERVICE_NAME') from dual
If you need to know this so that you can log in, find the file called TNSNAMES.ORA in $ ORACLE_HOME / rdbms / network / admin and the service name will probably be in the connection string.
Gary myers
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