title: Powershell command line parameters Null or Empty
body: <p>I have a script test.ps1 as follows:</p>
  
  <pre><code>param(     
        $a = "ValueA"
  )
  </code></pre>
  
  <p>now if call it from the command line from my msbuild project file as follows</p>
  
  <p>.\test.ps1 -a ""
  .\test.ps1 -a $null</p>
  
  <p>it does not assign the default value "ValueA" to $a. I would like to assign the default "Value" to $a even if the user pass it null or empty values. I know i can use <em>if</em> construct but i was wondering if there is a quick shorter way to achieve this. Any idea?</p>