To verify if the Schema compiles:
$ java -jar xml-validator-VERSION-jar-with-dependencies.jar -s /path/to/schema.xsd
To validate an XML (or a set of XMLs) against a schema:
$ java -jar xml-validator-VERSION-jar-with-dependencies.jar -s /path/to/schema.xsd \
/path/to/1.xml /path/to/2.xml
To view help:
$ java -jar xml-validator-VERSION-jar-with-dependencies.jar -h
This tool is available as part of "The Joy of Unix in Windows Tool Bundle":