#!/usr/bin/env bash

set -e

rev="$(cat /nix/var/nix/profiles/per-user/root/channels/nixpkgs/.git-revision)"
url="https://github.com/NixOS/nixpkgs/archive/$rev.tar.gz"
sha256="$(nix-prefetch-url --unpack "$url")"

cat <<EOF
# Generated by $(basename "$0") on $(date --rfc-3339=seconds)

builtins.fetchTarball {
  url = "$url";
  sha256 = "$sha256";
}
EOF