title: get list of sections from ini-file using shell (sed/awk)
body: <p>I want to create a var from the section names of an ini file like:</p>
  
  <pre><code>[foo]
  ; ...
  
  [bar]
  ; ...
  
  [baz:bar]
  ;...
  </code></pre>
  
  <p>now I need a var like</p>
  
  <pre><code>SECTIONS="foo bar baz"
  </code></pre>
  
  <p>thanks in advance</p>