Export full Lilypond file

[WeeSee]

I have tons of simple Lilypond files with one two or three voices.

As I understand this export feature the Lilypond file has to be extended to at least:

\include "oll-core/package.ily"
\loadPackage lilypond-export
opts.exporter = #exportHumdrum

and in \score{ ... }context:

\layout {
    \FileExport #opts 
}

While this work and gives excellent results, for many files this is a lot of manual work.

Is there a way to convert an unmodified Lilypond .ly file to a Humdum *.krn format using the command line without too many sed, awk,...?