Cwm (pronounced koom) is a general-purpose data processing software for the Semantic Web, similar to sed or awk for text files or XSLT for XML. It is a forward chaining semantic reasoner that can be used for querying, checking, transforming and filtering information. Its core language is RDF, extended to include rules, it can use RDF/XML or RDF/N3 (see Notation3 Primer) serializations. cwm can perform the following tasks: cwm was written in Python from 2000-10 onwards by Tim Berners-Lee and Dan Connolly of the W3C.