XMLStarlet Toolkit: Validate XML document(s)
Usage: PROG val <options> [ <xml-file-or-uri> ... ]
where <options>
  -w or --well-formed        - validate well-formedness only (default)
  -d or --dtd <dtd-file>     - validate against DTD
  --net                      - allow network access
#ifdef LIBXML_SCHEMAS_ENABLED
  -s or --xsd <xsd-file>     - validate against XSD schema
  -E or --embed              - validate using embedded DTD
#endif
#ifdef LIBXML_SCHEMAS_ENABLED
  -r or --relaxng <rng-file> - validate against Relax-NG schema
#endif
  -e or --err                - print verbose error messages on stderr
  -b or --list-bad           - list only files which do not validate
  -g or --list-good          - list only files which validate
  -q or --quiet              - do not list files (return result code only)

#ifdef LIBXML_SCHEMAS_ENABLED
NOTE: XML Schemas are not fully supported yet due to its incomplete
      support in libxml2 (see http://xmlsoft.org)

#endif