It's pre-installed on many systems, but if you find that typing "xmllint" on the command line gives you an error, you can download it as part of the free, open-source libxml2 package.
Here are some examples of using the xmllint command.
They provide a means for defining the structure, content and semantics of XML documents. XML Schema 1.0 was approved as a W3C Recommendation on and a second edition incorporating many errata was published on 28 October 2004; see reference list for pointers.
The XML Schema Working Group, part of the XML Activity, is responsible for the W3C's work on this topic -- for details see the Working Group's charter.
Because of confusion between XML Schema as a specific W3C specification, and the use of the same term to describe schema languages in general, some parts of the user community referred to this language as WXS, an initialism for W3C XML Schema, while others referred to it as XSD, an initialism for XML Schema Definition.
In Version 1.1 the W3C has chosen to adopt XSD as the preferred name, and that is the name used in this article.
The quickest way to get started with Kernow is to download the file for Kernow 1.6.1.
However, unlike most other schema languages, XSD was also designed with the intent that determination of a document's validity would produce a collection of information adhering to specific data types.
Such a post-validation infoset can be useful in the development of XML document processing software. It was the first separate schema language for XML to achieve Recommendation status by the W3C.
The specifications are now maintained by the W3C XML Core Working Group.
Tools · Usage · Resources · Specifications and Development XML Schemas express shared vocabularies and allow machines to carry out rules made by people.