nix-repl> d = derivation { name = "foo"; builder = "${bash}/bin/bash"; args = [ ./builder.sh ]; system = builtins.currentSystem; } nix-repl> :b d [1 built, 0.0 MiB DL] this derivation produced the following outputs: out -> /nix/store/gczb4qrag22harvv693wwnflqy7lx5pb-foo