lib,
}:
fetchurl {
  url = "https://raw.githubusercontent.com/NixOS/nixpkgs/23.11/.version";

  nativeBuildInputs = [ hello ];

  downloadToTemp = true;
  postFetch = ''
    ${lib.getExe hello} >> $downloadedFile
    mv $downloadedFile $out
  '';

  hash = "sha256-ceooQQYmDx5+0nfg40uU3NNI2yKrixP7HZ/xLZUNv+w=";
}
```

After building the package, the resulting file will have "Hello, world!" appended to it:

```shell
$ nix-build
(output removed for clarity)
/nix/store/ifi6pp7q0ag5h7c5v9h1c1c7bhd10c7f-version

$ cat /nix/store/ifi6pp7q0ag5h7c5v9h1c1c7bhd10c7f-version
23.11
Hello, world!
```

Note that the `hash` specified in the package is different than the hash specified in [](#ex-fetchers-fetchurl-nixpkgs-version), because the contents of the output have changed (even though the actual file that was downloaded is the same).
See [](#chap-pkgs-fetchers-caveats) for more details on how to work with the `hash` attribute when the output changes.
:::

## `fetchzip` {#sec-pkgs-fetchers-fetchzip}

Returns a [fixed-output derivation](https://nixos.org/manual/nix/stable/glossary.html#gloss-fixed-output-derivation) which downloads an archive from a given URL and decompresses it.

Despite its name, `fetchzip` is not limited to `.zip` files but can also be used with [various compressed tarball formats](#tar-files) by default.
This can extended by specifying additional attributes, see [](#ex-fetchers-fetchzip-rar-archive) to understand how to do that.

### Inputs {#sec-pkgs-fetchers-fetchzip-inputs}

`fetchzip` requires an attribute set, and most attributes are passed to the underlying call to [`fetchurl`](#sec-pkgs-fetchers-fetchurl).

The attributes below are treated differently by `fetchzip` when compared to what `fetchurl` expects:

`name` (String; _optional_)
: Works as defined in `fetchurl`, but has a different default value than `fetchurl`.

  _Default value:_ `"source"`.

`nativeBuildInputs` (List of Attribute Set; _optional_)
: Works as defined in `fetchurl`, but it is also augmented by `fetchzip` to include packages to deal with additional archives (such as `.zip`).

  _Default value:_ `[]`.

`postFetch` (String; _optional_)
: Works as defined in `fetchurl`, but it is also augmented with the code needed to make `fetchzip` work.

  :::{.caution}
  It is only safe to modify files in `$out` in `postFetch`.
  Consult the implementation of `fetchzip` for anything more involved.
  :::

  _Default value:_ `""`.

`stripRoot` (Boolean; _optional_)
: If `true`, the decompressed contents are moved one level up the directory tree.

  This is useful for archives that decompress into a single directory which commonly includes some values that change with time, such as version numbers.
  When this is the case (and `stripRoot` is `true`), `fetchzip` will remove this directory and make the decompressed contents available in the top-level directory.

  [](#ex-fetchers-fetchzip-simple-striproot) shows what this attribute does.

  This attribute is **not** passed through to `fetchurl`.

  _Default value:_ `true`.

`extension` (String or Null; _optional_)
: If set, the archive downloaded by `fetchzip` will be renamed to a filename with the extension specified in this attribute.

  This is useful when making `fetchzip` support additional types of archives, because the implementation may use the extension of an archive to determine whether they can decompress it.
  If the URL you're using to download the contents doesn't end with the extension associated with the archive, use this attribute to fix the filename of the archive.

  This attribute is **not** passed through to `fetchurl`.

  _Default value:_ `null`.

`recursiveHash` (Boolean; _optional_)
: Works [as defined in `fetchurl`](#sec-pkgs-fetchers-fetchurl-inputs-recursiveHash), but its default value is different than for `fetchurl`.

  _Default value:_ `true`.

`downloadToTemp` (Boolean; _optional_)
: Works [as defined in `fetchurl`](#sec-pkgs-fetchers-fetchurl-inputs-downloadToTemp), but its default value is different than for `fetchurl`.