title: grep match with string1 OR string2
body: <p>I want to grep 2 patterns in a file on <em><strong>Solaris UNIX</strong></em>. </p>
  
  <p>That is grep 'pattern1 <strong>OR</strong> pattern2' filename.</p>
  
  <p>The following command does NOT work:</p>
  
  <p><code>grep 'pattern1\|pattern2' filename</code></p>
  
  <p>What is wrong with this command?</p>
  
  <p><strong>NOTE:</strong> I am on Solaris</p>