title: Powershell variable for cmd argument
body: <p>I want to use a powershell variable for a cmd argument but I don't know how to make it. </p>
  
  <pre><code>function iptc($file)
  {        
          $newcredit = correspondance($credit)
          $cmd = '&amp; C:\exiftool\exiftool.exe -S -t -overwrite_original -Credit=$newcredit $file.FullName'
          Invoke-Expression $cmd
  }
  </code></pre>
  
  <p>For example newcredit can be "James" but in my case when I run the command -Credit will only be "$newcredit".</p>
  
  <p>Regards</p>