&lt;!DOCTYPE para PUBLIC "-//OASIS//DTD DocBook XML V4.1.2//EN"
          "http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd"&gt;
&lt;para&gt;
In &lt;acronym&gt;UNIX&lt;/acronym&gt;,
&lt;command&gt;ls&lt;/command&gt; is used to get a directory listing.
&lt;/para&gt;