Here is synopsis for 'xml c14n' command:

XMLStarlet Toolkit: XML canonicalization
Usage: xml c14n <mode> <xml-file> [<xpath-file>] [<inclusive-ns-list>]
where
  <xml-file>   - input XML document file name (stdin is used if '-')
  <xpath-file> - XML file containing XPath expression for
                 c14n XML canonicalization
    Example:
    <?xml version="1.0"?>
    <XPath xmlns:n0="http://a.example.com" xmlns:n1="http://b.example">
    (//. | //@* | //namespace::*)[ancestor-or-self::n1:elem1]
    </XPath>

  <inclusive-ns-list> - the list of inclusive namespace prefixes
                        (only for exclusive canonicalization)
    Example: 'n1 n2'

  <mode> is one of following:
  --with-comments         XML file canonicalization w comments (default)
  --without-comments      XML file canonicalization w/o comments
  --exc-with-comments     Exclusive XML file canonicalization w comments
  --exc-without-comments  Exclusive XML file canonicalization w/o comments

XMLStarlet is a command line toolkit to query/edit/check/transform
XML documents (for more information see http://xmlstar.sourceforge.net/)

EXAMPLE

# XML canonicalization
xml c14n --with-comments ../examples/xml/structure.xml ; echo $?

Input ../examples/xml/structure.xml

<a1>
  <a11>
    <a111>
      <a1111/>
    </a111>
    <a112>
      <a1121/>
    </a112>
  </a11>
  <a12/>
  <a13>
    <a131/>
  </a13>
</a1>

Output

<a1>
  <a11>
    <a111>
      <a1111></a1111>
    </a111>
    <a112>
      <a1121></a1121>
    </a112>
  </a11>
  <a12></a12>
  <a13>
    <a131></a131>
  </a13>
</a1>
0

EXAMPLE

# XML exclusive canonicalization
xml c14n --exc-with-comments ../examples/xml/c14n.xml ../examples/xml/c14n.xpath

Input

../examples/xml/c14n.xml

<n0:pdu xmlns:n0='http://a.example.com'>
<n1:elem1 xmlns:n1='http://b.example'>
content
</n1:elem1>
</n0:pdu>

../examples/xml/c14n.xpath

<XPath xmlns:n0="http://a.example.com" xmlns:n1="http://b.example">
(//. | //@* | //namespace::*)[ancestor-or-self::n1:elem1]
</XPath>

Output

<n1:elem1 xmlns:n1="http://b.example">
content
</n1:elem1>