title: appending a line after there is match for 2 pattern in Unix shell scripting
body: <p>I have a file like</p>
  
  <pre><code>nithin shetty
  sachin shetty
  pavan shetty
  </code></pre>
  
  <p>In this file i want to append "HELLO THIS IS ME",next line to the pattern "shetty". But the condition is that if the line matches for "nithin" , then don't append the line.
  I know how to append a line after a pattern match,</p>
  
  <pre><code>sed '/shetty/a\
    HELLO THIS IS ME
  ' filename`
  </code></pre>
  
  <p>But in this i don't want a line containing <code>nithin</code>. Output should be like this:</p>
  
  <pre><code>nithin shetty
  sachin shetty
    HELLO THIS IS ME
  pavan shetty
    HELLO THIS IS ME
  </code></pre>
  
  <p>Is it possible??</p>