title: Oracle Instant Client - SQL*Plus - ERROR: No TNS Listener (MacOSX)
body: <p>I am developing a web application that has to be connected with the ORACLE database.</p>
  
  <p>Presently I am working on macOS X and I have downloaded <a href="http://www.oracle.com/technetwork/topics/intel-macsoft-096467.html#ic_osx_inst" rel="nofollow noreferrer">Oracle Instant Client</a>.
  I am able to run <code>sqlplus</code>, but while logging in the interface I get the following error: </p>
  
  <pre><code>SQL*Plus: Release 12.2.0.1.0 Production on Sun Jul 8 10:55:48 2018
  
  Copyright (c) 1982, 2017, Oracle.  All rights reserved.
  Enter user-name: hr
  Enter password: 
  ERROR:
  ORA-12541: TNS:no listener
  </code></pre>
  
  <p>For your information, I have downloaded nothing except the client software by Oracle and installed it according to the official installation documentation.
  I really need to work on <code>sqlplus</code> for the database.</p>
  
  <p>PLEASE HELP.</p>
  
  <p>Also, could you please tell me how can I use <code>sqlplus</code> in my machine?</p>