How to force lp from CUPS to print in grayscale

Inkscape can convert between various vector graphics formats, including SVG to PDF. Although it's normally a GUI application, it can run in batch mode without an X server available.

inkscape --without-gui --export-pdf=foo.pdf foo.svg
lpr foo.pdf

Or if you want to print directly:

inkscape --without-gui --export-pdf=/dev/stdout foo.svg | lpr

Another possibility is the Apache Batik library. However, although there is a command line tool based on that library, Fop, it doesn't seem to have a way to use SVG input, so you'd have to write a bit of glue code in Java.

I figured it out by myself:

do

lpq

to get the job id and then

lp -i job-id -H resume

See this page for a reference. See also this one.