title: How to use sed to replace a config file's variable?
body: <p>I've been looking online for this answer and cannot seem to find it.</p>
  <p>I have a config file that contains:</p>
  <pre><code>VAR1=VALUE1
  VAR2=VALUE2
  VAR3=VALUE3
  VAR4=VALUE4
  VAR5=VALUE5
  VAR6=VALUE6
  </code></pre>
  <p>And I want to change <code>VAR5</code>'s value from <code>VALUE5</code> to <code>VALUE10</code>. Unfortunately, I do not know the value of <code>VALUE5</code> so I cannot search for it. So basically I need to use sed (or whatever) to replace the value of <code>VAR5</code> to another value.</p>