I am looking for a number or string that will be different in different runs of the same program. So far I can only think of using c(current_time) but that only changes once a minute. Is there a way to get the processid? That is what Stata uses for its temporary files but I don't see how to get it myself. The documentation for Stata random functions suggests saving the rng state, but that requires coordination across runs that I can't depend on. Any other suggestions?