title: Convert an Excel xls file to any XML format on unix?
body: <p>I receive an <code>xls</code> file (yes, with multiple sheets) regularly and have a whole bunch of business logic to apply on it. What I do <em>not</em> want is to have to use a 3rd-party library and then use library-specific commands like <code>sheet.cell(42,73)</code> mixed with the business logic all over the place. When the 3rd party lib expires, or Excel is updated, then everything would have to be engineered again.</p>
  
  <p>Thus, I'd like to have a slim <strong>xls-to-XML</strong> transformation phase. The XML-dialect does not really matter, "xmlx" would do, Open-Office, Open-Doc, whatever. It just has to be well-defined. If there are changes in this transformation later on, I hope I can handle that with a small xslt.</p>
  
  <p>In that XML I will write the business logic with the shipped xml-tools of my favorite language (python or perl), or even just xslt.</p>
  
  <p><strong>What is the <em>most reliable</em>, <em>slimmest</em> way to transform an <code>xls</code>-file to an <code>xml</code>-file, on a Linux machine?</strong> </p>
  
  <p>Notes:</p>
  
  <ul>
  <li>The file contains multiple sheets, if this weren't the case I would ask for the simplest converter to csv.</li>
  <li>The machine will be be 64- or 32 bit, but will not have any way to connect to a Windows-machine.</li>
  <li>I would rather not have to install an Office on that server, i.e. for scripting Open- or Libre-Office...</li>
  <li>Alas, I can not ask that the file is saved in any other format, like <code>xlsx</code>. <em>sigh</em></li>
  </ul>