title: linux use watch command with multiple calls
body: <p>How can I combine two (or more) calls by the <code>watch</code> command?<br/>
  Such that they are run together (serially) and <code>watch</code> shows their combined output?</p>
  
  <p>I.e. <code>watch command1 command2</code></p>
  
  <p>So to show the contents of two different directories:</p>
  
  <pre><code>watch $(ls dir1) $(ls dir2)
  </code></pre>
  
  <p>(The subshell parens were just added for clarity.)</p>
  
  <p>Of course I could create a script to run both commands, pipe the results into a tempfile and cat it for its contents periodically through watch, but I'd refrain from it if this is natively possible somehow. :)</p>
  
  <p>Subshells, grouping, process substitution did not help me, so I am out of luck and have no idea where to look now.</p>
  
  <p>Is this possible at all?</p>
  
  <p>UPDATE:</p>
  
  <pre><code>watch cat &lt;(ls dir1) &lt;(ls dir2)
  </code></pre>
  
  <p>gives me on the first iteration what I'd love to see refreshed periodically, but not repeatedly. :(</p>