title: Sed using a variable for line number restriction
body: <p>I want to do a search and replace on a line with specific line number. However, I want to be able to use a variable for the Line Number itself.</p>
  
  <p>For instance, if I wanted to replace the number 4 with a number 5 on line 180. I would use the following code.</p>
  
  <pre><code>sed '180 s/4/5/' file
  </code></pre>
  
  <p>My Question is how do I use a variable for the line number?</p>
  
  <pre><code>sed '$variable s/4/5/' file
  </code></pre>