title: awk and multilines matching (sub-regex)
body: <p>I am trying to use awk to parse a multiline expression. A single one of them looks like this:</p>
  
  <pre><code>_begin  hello world !
  _attrib0    123
  _attrib1    super duper
  _attrib1    yet another value
  _attrib2    foo
  _end
  </code></pre>
  
  <p>I need to extract the value associated to _begin and _attrib1. So in the example, the awk script should return (one per line): </p>
  
  <pre><code>hello world ! super duper yet another value 
  </code></pre>
  
  <p>The separator used is a tab (\t) character. Spaces are used only within strings.</p>