I did not want GUI, just super simple caffeinate-like CLI. Also I wanted auto-shutdown afterwards.
https://www.google.com/search?q=site%3Agithub.com+keep+mac+o...
First one I used was around 9 years ago. Nearly melted my backpack with the hot Intel CPU!
If you don't want to install anything, you can disable sleep with the built in tools: sudo pmset -a disablesleep 1
The API call that 'sudo pmset -a disablesleep 1' does is literally the first thing caffeine+ does. But is only part of the full solution: As soon as the lid closes the command is automatically reverted so you can't forget to do it yourself. Also if you kill caffeinate+, the MacBook is put to sleep when the lid is still closed.
You forgot to argue about the LOC vs file count issue.
Also, you are wrong: None does auto sleep on script exit.
And, I've been using these for around 9 years. A few I tried most definitely did re-enable on exit. Not sure why file count is a concern, or especially LOC (a truly horrendous metric to target, with the outcome being unintelligible code golf when optimized for). All that I used were exactly one file I was concerned with: a binary or shell script.
This has become strange. Cheers!
sudo bash -c 'trap "pmset -a disablesleep 0" EXIT; s=; while :; do if lsof -nP -iTCP:22 -sTCP:ESTABLISHED >/dev/null 2>&1 || pgrep -xq ssh;
then n=1; else n=0; fi; [ "$n" != "$s" ] && pmset -a disablesleep $n && s=$n; sleep 10; done'