title: "sed" command in bash
body: <p>Could someone explain this command for me:</p>
  
  <pre><code>cat | sed -e 's,%,$,g' | sudo tee /etc/init.d/dropbox &lt;&lt; EOF
     echo "Hello World"
  EOF
  </code></pre>
  
  <p>What does the "sed" command do?</p>