[m12k]

KeepingYouAwake is a nice open source alternative that you can find on GitHub

[duskwuff]

And for simple use cases, Apple ships a "caffeinate" command-line utility with the OS that might just do what you want.

[stevehawk]

so swap one stimulant drug name for another

[toyodas]

Thanks, I use my own I wrote for hammerspoon.