title: "getpwnam() failed" in /bin/sh only when called from cron
body: <p>Here's the content of my crontab file:</p>
  
  <pre><code>SHELL=/bin/bash
  PATH=/sbin:/bin:/usr/sbin:/usr/bin
  MAILTO="example@example.com"
  
  */5 * * * * sh /robot/1/master.sh &gt;/dev/null 2&gt;&amp;1
  */5 * * * * sh /robot/2/master.sh &gt;/dev/null 2&gt;&amp;1
  */5 * * * * sh /robot/3/master.sh
  */5 * * * * sh /robot/4/master.sh &gt;/dev/null 2&gt;&amp;1
  */5 * * * * sh /robot/5/master.sh &gt;/dev/null 2&gt;&amp;1
  </code></pre>
  
  <p>This is the error that keeps showing in <code>/var/log/cron</code> when it tries to run:</p>
  
  <pre><code>crond[669]: (sh) ERROR (getpwnam() failed)
  </code></pre>
  
  <p>If I run any of these files manually, they work without any issues.</p>
  
  <p>What's wrong with the crontab file?</p>