lass="keyword">val</span> file_err : 
  <span>string <span class="arrow">&#45;&gt;</span></span>
  <span><span><span>(<span class="type-var">'stdin</span>, <span class="type-var">'stdout</span>, <a href="#type-stderr">stderr</a>)</span> <a href="Core/Cmd/index.html#type-t">Cmd.t</a></span> <span class="arrow">&#45;&gt;</span></span>
  <span><span>(<span class="type-var">'stdin</span>, <span class="type-var">'stdout</span>, <a href="#type-file">file</a>)</span> <a href="Core/Cmd/index.html#type-t">Cmd.t</a><