cc @grahamc

@grahamc Is there anything that's blocking this PR from been merged? We are planning to put /nix on a separate partition and it would be very convenient if the upstream installer would support this case :)

I am replacing if [ -d /nix ] with if [ -e /nix/store -o -e /nix/var ] for the same purpose.

This pull request has been mentioned on Nix community. There might be relevant details there:

https://discourse.nixos.org/t/does-a-debian-package-for-nix-2-exist/2265/5

@orivej I replaced implementation with your version since it seems to be more reliable, thanks for the input :)

For someone who will have the same issue in the future [1], we ended up using these packages kindly provided by @Mic92 and @dezgeg: https://github.com/Mic92/nix-fpm-multiuser/releases.

This can be closed; a similar fix was merged in #3054.