/usr/bin/faust2eps is in faust 0.9.46-2.
This file is owned by root:root, with mode 0o755.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11  | #!/bin/bash
faust2svg $@
for d in $@; do
    for f in $d-svg/*.svg; do
        inkscape -E ${f%.svg}.eps $f
        rm $f
    done
    mv $d-svg $d-eps
done
 |