I tried to run unparse by providing the input on stdin and I got this error:
[dfdl] (0.16.0)$ echo -ne 'xmlns:fn="http://www.w3.org/2005/xpath-functions" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:dfdl="http://www.ogf.org/dfdl/dfdl-1.0/" xmlns:tns="http://www.example.org/example1/" xmlns="http://www.w3.org/2001/XMLSchema"><tns:row><tns:cell>0</tns:cell></tns:row></tns:matrix>' | daffodil-cli/target/universal/stage/bin/daffodil unparse -s daffodil-test/src/test/resources/edu/illinois/ncsa/daffodil/section06/entities/charClassEntities.dfdl.xsd -r matrix
[error] /home/jchab/NGF/dfdl/standardInput (No such file or directory)