Derivation stdenv cant execute bash scripts

Help
1

I’m trying to package Urbackup but i cant run bash scripts in the derivation. Not even simple ones like the teste.sh that i created to test and that just run echo ‘test!’.

The error message i get is ./teste.sh: cannot execute: required file not found.

The following is my nix expression:

with import <nixpkgs> {};
 
stdenv.mkDerivation rec {
  pname = "urbackup-server";
  version = "2.5.20";

  src = fetchgit {
    url = "https://github.com/uroni/urbackup_backend.git";
    rev = "refs/tags/${version}";
    sha256 = "sha256-brP7nYikbIvQP/K+qSKyd8eHWUIK9Ai/4qP09ptr+lE=";
  };

  buildInputs = [
    cryptopp
    curlWithGnuTls
  ];

  configurePhase = ''
    runHook preInstall

    touch teste.sh
    echo '#!/usr/bin/env bash' >> teste.sh
    echo 'echo 'echo test! >> teste.sh
    chmod +x teste.sh
    ./teste.sh

    ./switch_build.sh server
    autoreconf --install
    ./configure

    runHook postInstall
  '';

  buildFlags = [
    "-j8"
  ];

  enableParallelBuilding = true;

  meta = with lib; {
    description = "Easy to setup Open Source client/server backup system";
    longDescription = "An easy to setup Open Source client/server backup system, that through a combination of image and file backups accomplishes both data safety and a fast restoration time";
    homepage = "https://www.urbackup.org/index.html";
    license = licenses.agpl3Plus;
    platforms = platforms.linux;
  };
}

I’m running nix inside Debian Trixie:

$ nix --version
nix (Nix) 2.25.2

I can access the files normally with ls cat.

2

Does /usr/bin/env even exist in the sandbox? Better off just running bash test.sh or whatever.

3

You’re right! it now executes.

Do you know if running bash is the default way to running scripts inside derivations?

4

If you’re making your own script as part of the build, you could probably just write #!bash as the shebang, or better, use writeShellApplication which gets shellcheck-ed and put the call in nativeBuildInputs. If you’re trying to use someone else’s existing script, I don’t see any other way to handle it (besides running sh or bash or whatever directly) if it’s using a shebang that points at a nonexistent file. Well, you could patch the file, I suppose, with patchShebangs --build, but seems kinda overkill for something only used during the build :person_shrugging:

1 Like