title: xmlstarlet replace xml node value
body: <p>I'm new using xmlstarlet.  I'd like to know how to change the value of xml node using  xmlstarlet.</p>
  
  <p>I tried something.
  xmlstarlet ed --inplace -u '/file_input/uri'  'string("s3://my_source")' template.xml > output.xml</p>
  
  <p>doesn't work.</p>
  
  <p>My expected output as  <strong>s3://my_source</strong> and <strong>s3://mydestination</strong>. I'd like to change <strong>source_path</strong> and <strong>destination_path</strong> node.</p>
  
  <pre><code>&lt;?xml version="1.0" encoding="UTF-8"?&gt;
  &lt;job version="2.10.8"&gt;
    &lt;input&gt;
      &lt;deblock_enable&gt;Auto&lt;/deblock_enable&gt;
      &lt;deblock_strength&gt;0&lt;/deblock_strength&gt;
      &lt;no_psi&gt;false&lt;/no_psi&gt;
      &lt;order&gt;1&lt;/order&gt;
      &lt;timecode_source&gt;zerobased&lt;/timecode_source&gt;
      &lt;file_input&gt;
        &lt;certificate_file nil="true"/&gt;
        &lt;password&gt;upass&lt;/password&gt;
        &lt;uri&gt;source_path&lt;/uri&gt;
        &lt;username&gt;uname&lt;/username&gt;
      &lt;/file_input&gt;
      &lt;file_group_settings&gt;
        &lt;rollover_interval nil="true"/&gt;
        &lt;destination&gt;
          &lt;password&gt;upass&lt;/password&gt;
          &lt;username&gt;uname&lt;/username&gt;
          &lt;uri&gt;destination_path&lt;/uri&gt;
        &lt;/destination&gt;
      &lt;/file_group_settings&gt;
    &lt;/input&gt;
  &lt;/job&gt;
  </code></pre>
  
  <p>Thank you very much</p>