title: How to create a file on the command line and pass as an argument to a command
body: <p>I call a library like this:</p>
  <pre><code># myFile.txt is a file that already exists read by `grun`
  $ grun TestLexer tokens -tokens myFile.txt
  </code></pre>
  <p>However, instead of passing a file, I'd like to create/re-create that every time I run it in the command-line such as something like the following:</p>
  <pre><code>$ grun TestLexer tokens -tokens &quot;echo 'x+1' &gt; myFile.txt&quot;
  </code></pre>
  <p>What would be the proper way to actually do that?</p>