We can test our connection, here with the EZConnect details defined earlier, on a Linux box. First show what OS user we are running as:
$ id
uid=500(oracle) gid=501(oinstall) groups=501(oinstall) ,502(dba)
Now log in to SQL with an EZConnect string:
$sqlplus /@oraprod1/PAOLOXDB.megacorp.com
SQL*Plus: Release 11.2.0.1.0 Production on Thu Nov 12 14:50:41 2015
Copyright (c) 1982, 2009, Oracle. All rights reserved.
Connected to:
Oracle Database 11g Enterprise Edition Release 11.2.0.1.0 - 64bit Production
With the Partitioning, OLAP, Data Mining and Real Application Testing options
SQL> show user
USER is "Precisely"
SQL>
Note that no user name or password was required to start a session to this database through SQL*Plus, but the appropriate credentials were used and we are signed into Oracle as Precisely even though the Linux user is oracle.