title: How to redirect an output file descriptor of a subshell to an input file descriptor in the parent shell?
body: <p>(In BASH) I want a subshell to use a non-STDOUT non-STDERR file descriptor to pass some data back to the parent shell. How can I do that? Eventually I would love to save the data into some variable of the parent shell.</p>
  
  <pre><code>(
    # The following two lines show the behavior of the subshell.
    # We cannot change them.
    echo "This should go to STDOUT"
    echo "This is the data I want to pass to the parent shell" &gt;&amp;3
  )
  #...
  data_from_subshell=... # Somehow assign the value of &amp;3 of the
                         # subshell to this variable
  </code></pre>
  
  <p>EDIT:
  The subshell runs a black-box program that writes to STDOUT and &amp;3.</p>