install.sh

# macOS support for 10.10 or higher
if [[ "$(uname -s)" = "Darwin" ]]; then
    if [[ $(($(sw_vers -productVersion | cut -d '.' -f 2))) -lt 10 ]]; then
        echo "$0: macOS $(sw_vers -productVersion) is not supported, upgrade to 10.10 or higher"
        exit 1
    fi

    printf '\e[1;31mSwitching to the Multi-User Darwin Installer\e[0m\n'
    exec "$self/install-darwin-multi-user"
    exit 0
fi

output

#> ./install
performing a single-user installation of Nix...
directory /nix does not exist; creating it by running ‘�� using sudo
copying Nix to /nix/store.....................................
initialising Nix database...
installing ‘nix-1.11.15’
warning: Nix search path entry ‘/nix/var/nix/profiles/per-user/root/channels’ does not exist, ignoring
building path(s) ‘/nix/store/asgx51wzbswgg1j506pg7sq4jyclv0qn-user-environment’
error: setting uid: Operation not permitted
error: cannot kill processes for uid ‘30001’: failed with exit code 1
./install: unable to install Nix into your default profile