title: How to write the usage notes
body: <p>My script can be called like this:</p>
  
  <pre><code>myScript -a some_name
  myScript -a all
  myScript -b some_name
  myScript -b all
  myScript -c
  </code></pre>
  
  <p>How do I write its usage notes? I know <code>[]</code> mean optional arguments and <code>|</code> means alternative but in my case I would need <em>nested alternative</em>, something like:</p>
  
  <pre><code>usage myScript (-a some_name | all) | (-b some_name | all) | -c
  </code></pre>
  
  <p>Now I don't think I can use <code>()</code> for this purpose so how else can I write this? Do I have to write it in multiple lines instead or is there a better way?</p>
  
  <pre><code>myScript -a some_name | all
  myScript -b some_name | all
  myScript -c
  </code></pre>
  
  <p>I mean this would still be ok in my case but if I had more nested alternatives it would get really verbose.</p>
  
  <p>Also is there any exhaustive source describing the standard unix/linux usage notes?</p>