Can my render script detect being umped by higher priority jobs?
Not without clever scripting. Usually the desire to do this stems from wanting to clean up left over temporary files generated by renders. In most cases, you can avoid left over files by putting temporary files in $RUSH_TMPDIR, which rush cleans automatically, even after bumps. Bumps and dumps use SIGKILL to kill the render script and its children. This signal is NOT trappable. There’s a reason: Under many circumstances SIGTERM, the ‘trappable’ kill is not effective, especially during heavy rendering, causing bumped frames not to bump, screwing up unattended use, and leaving processors unproductive. Since bumps can happen just as readily as dumps, both use SIGKILL, untrappable, and always effective (except in pathological cases where the process is hung). So do not expect to be able to trap interrupts to detect bumps/dumps.