Running dvips -z produces two temporary files head.tmp and body.tmp. So when I run dvips on different files concurrently in the same dir, sometimes the different head.tmp or body.tmp "overlap" (AFAICT).

Is there any way to change the name of these auxiliary files?

A MWE can be as follows (here I'm running dvips multiple times on the same file, but I think the problem is the same). If you run it, sometimes you end up with errors such as dvips: ! Could not find header file body.tmp..

#!/bin/bash

cat <<EOF > mwe.tex
\documentclass{article}
\usepackage{kantlipsum}
\begin{document}
\kant
\end{document}
EOF

latex mwe

dvips -z mwe -o & \
dvips -z mwe -o & \
dvips -z mwe -o & \
dvips -z mwe -o &