# Sample DocBook Document

John Doe

## Introduction

This is a valid DocBook 5.0 document that can be used to test validation against arbitrary schemas using the vnu CLI validator with the --schema option.

### Background

DocBook is a semantic markup language for technical documentation. It was originally intended for writing technical documents related to computer hardware and software.

## Usage Examples

To validate this document against the DocBook 5.1 schema, use:

    java -cp vnu.jar nu.validator.client.SimpleCommandLineValidator \
        --schema https://docbook.org/xml/5.1/rng/docbook.rng \
        --xml \
        --format text \
        docbook-valid.xml

The validator should report no errors for this document.