Does GNU Shepherd support some form of sanboxing?

systemd has many options to reduce the privileges of a service: like running as a normal user with only certain POSIX capabilities, setting up a mount namespace with a limited view of the root filesystem, locking down which system calls can be invoked, etc.

Two notes from reading the first several paragraphs:

1. It seems one needs to know some Scheme in order to write these files:

https://www.scheme.org/

I don't think it's possible to just "wing it" by copy-and-paste.

2. I did not understand the introductory paragraph about how services "extend" each other. Does every service have hooks for possible extensions? What if a new service doesn't fit existing extension hooks?

(I can understand service dependencies of course, but it seems to go beyond that.)

For day to day use, what are the benefits for gnu guix? From it’s website, what I could understand is it provides installation of different version of the same package, similar to rbenv or conda. Apart from this, is there anything else that will be considered useful over something like aptitude?

From a quick glance, Guix seems to have a similar learning curve as Nix (at least it's based on Scheme, which I know). Is that impression correct? Anyway, I didn't find this “intuitively comprehensible” as an outsider.

Guix is a reimagining of the concepts of Nix with Guile/Scheme instead of the Nix language, so they are very similar in overall feel, but differ in the details (e.g. GNU Shepherd vs systemd).

As for learning curve, I find Nix substantially easier, since the language is much simpler (JSON-like with lazy-functions) and doesn't need all that weirdness that result from using Scheme as configuration language (lots of quoting, module system, etc.)

As someone who has tried both, I found the learning curve for Guix much more pleasant than for Nix. With Nix, the community is for sure a lot larger, and more things are available (notably it is a lot faster, too). But I could never get everything clear in my head, how it hangs together, and the community seemed very much more fragmented than with Guix. I think the Guix documentation and manual, as well as the CLI and secondary docs written in people's blogs, were much easier to get a handle on than with Nix. Flakes are a great example, I still have no idea what a flake is, they are still an experimental feature, and I have no idea how I should think about them. I've been using NixOS full time for 3 years by the way.

I also think the shepherd alone is almost a killer app relative to something like systemd. I had to write a service myself for restarting ssh tunnels, and I could even do "advanced" things like templated configuration, almost trivially. It felt like a superpower, relative to systemd services.

    nix.settings.experimental-features = [ "nix-command" "flakes" ];

   nix run github:user/project?ref=v0.2.0rc1

Correct, and it's Linux-only and more hardcore FOSS (i .e. they don't have any blessed way to use non-free software).

I'm not sure why it's being sold as an alternative to Nix/NixOS