nalt

wget https://gist.githubusercontent.com/nalt/dfa2abc9d2e3ae4feb82ca5608090387/raw/roslaunch.dtd
find /opt/ros -iname '*.launch' -exec xmllint --valid --dtdvalid roslaunch.dtd  --noout  {} ';' 2>&1 | grep -v "no DTD found" | grep -v '<launch>'
# Missing DOCTYPE is reported as an error.
# $(...) will be rejected by this DTD for enum attributes