title: How can I send the stdout of one process to multiple processes using (preferably unnamed) pipes in Unix (or Windows)?
body: <p>I'd like to redirect the stdout of process proc1 to two processes proc2 and proc3:</p>
  
  <pre><code>         proc2 -&gt; stdout
         /
   proc1
         \ 
           proc3 -&gt; stdout
  </code></pre>
  
  <p>I tried</p>
  
  <pre><code> proc1 | (proc2 &amp; proc3)
  </code></pre>
  
  <p>but it doesn't seem to work, i.e.</p>
  
  <pre><code> echo 123 | (tr 1 a &amp; tr 1 b)
  </code></pre>
  
  <p>writes</p>
  
  <pre><code> b23
  </code></pre>
  
  <p>to stdout instead of </p>
  
  <pre><code> a23
   b23
  </code></pre>