title: What does the special character "!" mean in PowerShell?
body: <p>What does the special character <code>!</code> mean in PowerShell?</p>
  
  <p>Or a site which lists all special characters and meaning.
  Example:</p>
  
  <pre><code>$string = blah
  !$String
  </code></pre>
  
  <p>(Returns $false)</p>