title: curl: read headers from file
body: <p>After the --dump-header writes a file, how to read those headers back into the next request?  I would like to read them from a file because there are a number of them.</p>
  <p>I tried standard in: <code>cat headers | curl -v -H - ...</code></p>
  <p>I'm actually using the feature in Firebug to &quot;Copy Request Headers&quot; and then saving those to a file.  This appears to be the same format.</p>