title: Find string and replace line in linux
body: <p>I'd like to do the following, but I can't seem to find an elegant way to do it.</p>
  
  <p>I have a text file that looks like this:</p>
  
  <pre><code>..more values
  stuff = 23   
  volume = -15
  autostart = 12
  more values..
  </code></pre>
  
  <p>Now the "volume" value may change, depending on the circumstance.  I need a script that can find that line of text with "volume = xxx" then replace it with the line "volume = 0".  What is an elegant solution to this?  This line in the text is not guaranteed to be the first line, so I need a way to find it first.</p>