Looks like a pipe is also supported; you just need to pass `-` as the name of the file to `latexmlpost`.
latexml mydoc.tex | latexmlpost --dest=mydoc.html --format=html5 -
latexmlc --dest=mydoc.html --format=html5 mydoc.tex
Looks like a pipe is also supported; you just need to pass `-` as the name of the file to `latexmlpost`.