title: can't call yum on an Amazon EC2 instance
body: <p>I'm using an Amazon EC2 instance. I fail to call yum both with sudo:</p>
  
  <pre><code>$ sudo yum update -y
  sudo: unable to execute /usr/bin/yum: No such file or directory
  </code></pre>
  
  <p>and without sudo:</p>
  
  <pre><code>$ yum update -y
  -bash: /usr/bin/yum: /usr/bin/python2.7: bad interpreter: No such file or directory
  </code></pre>
  
  <p>It claims to not have a file at <code>/usr/bin/yum</code>. However, this file exists:</p>
  
  <pre><code>$ [ -f /usr/bin/yum ] &amp;&amp; echo "Found" || echo "Not found"
  Found
  </code></pre>