Probably because Linux doesn't really have a good model for ad-hoc permission restrictions. It has enough bits to make a Docker container out of, but that's a full new system. You can't really restrict a subprocess to only write files under this directory.
For plain Linux, chmod, chmod's sticky bit and setfacl provide extensive ad hoc permissions restricting. Your comment is 4 hours old, I'm surprised I'm the first person to help correct its inaccuracy.
This doesn't meet the requirement. It doesn't restrict a certain subprocess to only write in a certain directory. You are just saying these things to quickly shut down the uncomfortable thought that Linux can't do something.
Or perhaps you need to go read my original comment again as you missed the premise. But if you feel you have perfect memory then perhaps look at something like firejail or read more about systemd.
But your premise of Linux "can't" do something is rather absurd. It's Linux, you can do anything, even if no one has done that thing before.
The reason people didn't respond earlier is because they probably assumed it a waste of their time. I know I have wasted mine
You chose to respond to a question I posed, with an extremely poor answer. I was very specific about restricting a certain subprocess to only write to a certain directory. Your answer does not do that. I pointed that out. Now you are defending that answer by claiming you were actually answering something else entirely. This is nonsensical.
