title: Is there a gnu/unix command to both save a file without consuming stream?
body: <p>I seem to faintly remember some unix command that allows you to save out put while piping to the next program.</p>
  
  <p>Eg.</p>
  
  <pre><code>echo "hello world!"  \
  | mystery_command hello.txt \
  | sed -E "s/hello/goodbye/g" \
  &gt; goodbye.txt
  </code></pre>
  
  <p>Would both create a file called hello.txt with "hello world!" as contents. and a file called goodbye.txt with "goodbye world!" as contents.</p>