title: Is there a "standard" format for command line/shell help text?
body: <p>If not, is there a de facto standard? Basically I'm writing a command line help text like so:</p>
  
  <pre class="lang-none prettyprint-override"><code>usage: app_name [options] required_input required_input2
    options:
      -a, --argument     Does something
      -b required     Does something with "required"
      -c, --command required     Something else
      -d [optlistitem1 optlistitem 2 ... ]     Something with list
  </code></pre>
  
  <p>I made that from basically just reading the help text of various tools, but is there a list of guidelines or something? For example, do I use square brackets or parentheses? How to use spacing? What if the argument is a list? Thanks! </p>