Validating XML with xmllint

The following commands show you how to validate an XML file against a DTD or XSD using xmllint.

To validate an XML file against:

• a DTD stored in the same file:

xmllint --valid --noout fileWithDTD.xml

• a DTD stored in a separate file:

xmllint --dtdvalid DTD.dtd --noout fileWithoutDTD.xml

• an XSD stored in a separate file:

xmllint --schema schema.xsd --noout file.xml

The --noout option suppresses the output of the xml file.

Example
To validate:

<countries>
  <country name="Afghanistan" population="22664136" area="647500">
    <language percentage="11">Turkic</language>
    <language percentage="35">Pashtu</language>
    <language percentage="50">Afghan Persian</language>
  </country>
  <country name="Albania" population="3249136" area="28750"/>
  <country name="Algeria" population="29183032" area="2381740">
    <city>
      <name>Algiers</name>
      <population>1507241</population>
    </city>
  </country>
</countries>

against:

<!ELEMENT countries (country*)>
<!ELEMENT country (language|city)*>
<!ATTLIST country name CDATA #REQUIRED>
<!ATTLIST country population CDATA #REQUIRED>
<!ATTLIST country area CDATA #REQUIRED>
<!ELEMENT language (#PCDATA)>
<!ATTLIST language percentage CDATA #REQUIRED>
<!ELEMENT city (name, population)>
<!ELEMENT name (#PCDATA)>
<!ELEMENT population (#PCDATA)>

use the command:

xmllint --dtdvalid countries.dtd --noout countries.xml