Joel,

No there isn't - and that's one reason why I don't use scripts
for daily housekeeping/processing; we use perl scripts for all
(serial) tasks we might want to interrupt.  As far as I know
there is no plan to enhance - with e.g. 'cancel script'.  I do
know that development are aware of the need for this feature.

The only workaround is to halt/restart the server but even that
could be dubious depending on exactly what commands are in the
script - you really want to halt when there are no processes
running.

Best regards, Sheelagh