title: In Shell script process variables in text
body: <p>I have a file 'test.txt', the contents is &quot;SomeText_$(date '+%Y%m%d')&quot;.
  When reading this into a variable with:</p>
  <pre><code>txt=`cat test.txt`
  </code></pre>
  <p>Then I try to print with</p>
  <pre><code>echo $txt
  </code></pre>
  <p>This prints: &quot;SomeText_$(date '+%Y%m%d')&quot;
  How do I print this so I receive &quot;SomeText_20200904&quot;</p>