if test -n "$HOME" && test -n "$USER"

    # Set up the per-user profile.

    set NIX_LINK $HOME/.nix-profile

    # Set up environment.
    # This part should be kept in sync with nixpkgs:nixos/modules/programs/environment.nix
    set --export NIX_PROFILES "/nix/var/nix/profiles/default $HOME/.nix-profile"

    # Set $NIX_SSL_CERT_FILE so that Nixpkgs applications like curl work.
    if test -n "$NIX_SSH_CERT_FILE"
        : # Allow users to override the NIX_SSL_CERT_FILE
    else if test -e /etc/ssl/certs/ca-certificates.crt # NixOS, Ubuntu, Debian, Gentoo, Arch
        set --export NIX_SSL_CERT_FILE /etc/ssl/certs/ca-certificates.crt
    else if test -e /etc/ssl/ca-bundle.pem # openSUSE Tumbleweed
        set --export NIX_SSL_CERT_FILE /etc/ssl/ca-bundle.pem
    else if test -e /etc/ssl/certs/ca-bundle.crt # Old NixOS
        set --export NIX_SSL_CERT_FILE /etc/ssl/certs/ca-bundle.crt
    else if test -e /etc/pki/tls/certs/ca-bundle.crt # Fedora, CentOS
        set --export NIX_SSL_CERT_FILE /etc/pki/tls/certs/ca-bundle.crt
    else if test -e "$NIX_LINK/etc/ssl/certs/ca-bundle.crt" # fall back to cacert in Nix profile
        set --export NIX_SSL_CERT_FILE "$NIX_LINK/etc/ssl/certs/ca-bundle.crt"
    else if test -e "$NIX_LINK/etc/ca-bundle.crt" # old cacert in Nix profile
        set --export NIX_SSL_CERT_FILE "$NIX_LINK/etc/ca-bundle.crt"
    end

    # Only use MANPATH if it is already set. In general `man` will just simply
    # pick up `.nix-profile/share/man` because is it close to `.nix-profile/bin`
    # which is in the $PATH. For more info, run `manpath -d`.
    if set --query MANPATH
      set --export --prepend --path MANPATH "$NIX_LINK/share/man"
    end

    fish_add_path --prepend --global "$NIX_LINK/bin"
    set --erase NIX_LINK
end
