How to export graphics to SVG in script executed through cron?

I can somewhat reproduce this error. Except for me, if I try to export a graphic with no display set, the kernel just hangs. The answer is to use an Xvfb display server, as described here.

I have the file, exportSVG.m, with the contents

plot = Plot[x, {x, -3, 3}];
Export["/home/jasonb/some.svg", plot];

Then another file, exportSVG.sh,

#!/usr/bin/env bash

xvfb-run /usr/local/bin/wolframscript -script /home/jasonb/exportSVG.m

If I add this to my crontab with out the xvfb-run, it hangs. If I add in that command, it works. You'll need to ensure you have it installed, check via which xvfb-run.