### Example Nix Manifest File

Source: https://github.com/nixos/nix/blob/master/doc/manual/source/command-ref/files/manifest.nix.md

This is an example of a manifest.nix file after installing the 'hello' package. It details the package's metadata, output path, system, and type.

```nix
[{
  meta = {
    available = true;
    broken = false;
    changelog =
      "https://git.savannah.gnu.org/cgit/hello.git/plain/NEWS?h=v2.12.1";
    description = "A program that produces a familiar, friendly greeting";
    homepage = "https://www.gnu.org/software/hello/manual/";
    insecure = false;
    license = {
      deprecated = false;
      free = true;
      fullName = "GNU General Public License v3.0 or later";
      redistributable = true;
      shortName = "gpl3Plus";
      spdxId = "GPL-3.0-or-later";
      url = "https://spdx.org/licenses/GPL-3.0-or-later.html";
    };
    longDescription = ''
      GNU Hello is a program that prints "Hello, world!" when you run it.
      It is fully customizable.
    '';
    maintainers = [{
      email = "edolstra+nixpkgs@gmail.com";
      github = "edolstra";
      githubId = 1148549;
      name = "Eelco Dolstra";
    }];
    name = "hello-2.12.1";
    outputsToInstall = [ "out" ];
    platforms = [
      "i686-cygwin"
      "x86_64-cygwin"
      "x86_64-darwin"
      "i686-darwin"
      "aarch64-darwin"
      "armv7a-darwin"
      "i686-freebsd13"
      "x86_64-freebsd13"
      "aarch64-genode"
      "i686-genode"
      "x86_64-genode"
      "x86_64-solaris"
      "js-ghcjs"
      "aarch64-linux"
      "armv5tel-linux"
      "armv6l-linux"
      "armv7a-linux"
      "armv7l-linux"
      "i686-linux"
      "m68k-linux"
      "microblaze-linux"
      "microblazeel-linux"
      "mipsel-linux"
      "mips64el-linux"
      "powerpc64-linux"
      "powerpc64le-linux"
      "riscv32-linux"
      "riscv64-linux"
      "s390-linux"
      "s390x-linux"
      "x86_64-linux"
      "mmix-mmixware"
      "aarch64-netbsd"
      "armv6l-netbsd"
      "armv7a-netbsd"
      "armv7l-netbsd"
      "i686-netbsd"
      "m68k-netbsd"
      "mipsel-netbsd"
      "powerpc-netbsd"
      "riscv32-netbsd"
      "riscv64-netbsd"
      "x86_64-netbsd"
      "aarch64_be-none"
      "aarch64-none"
      "arm-none"
      "armv6l-none"
      "avr-none"
      "i686-none"
      "microblaze-none"
      "microblazeel-none"
      "msp430-none"
      "or1k-none"
      "m68k-none"
      "powerpc-none"
      "powerpcle-none"
      "riscv32-none"
      "riscv64-none"
      "rx-none"
      "s390-none"
      "s390x-none"
      "vc4-none"
      "x86_64-none"
      "i686-openbsd"
      "x86_64-openbsd"
      "x86_64-redox"
      "wasm64-wasi"
      "wasm32-wasi"
      "x86_64-windows"
      "i686-windows"
    ];
    position =
      "/nix/store/7niq32w715567hbph0q13m5lqna64c1s-nixos-unstable.tar.gz/nixos-unstable.tar.gz/pkgs/applications/misc/hello/default.nix:34";
    unfree = false;
    unsupported = false;
  };
  name = "hello-2.12.1";
  out = {
    outPath = "/nix/store/src1vzij2z0slnakrsbpqpk20389z0k6-hello-2.12.1";
  };
  outPath = "/nix/store/src1vzij2z0slnakrsbpqpk20389z0k6-hello-2.12.1";
  outputs = [ "out" ];
  system = "x86_64-linux";
  type = "derivation";
}]

```

--------------------------------

### Build and Install Nix from Source

Source: https://github.com/nixos/nix/blob/master/doc/manual/source/installation/building-source.md

Clone the Nix repository, set up the build environment with Meson, compile the code with Ninja, and install the built binaries. The installation path can be customized.

```bash
git clone https://github.com/NixOS/nix.git
cd nix
meson setup build
cd build
ninja
(sudo) ninja install
```

--------------------------------

### Install Nix

Source: https://github.com/nixos/nix/blob/master/HACKING.md

Run the installPhase to install Nix to the specified output directory and verify the installation by checking the version.

```console
[nix-shell]$ installPhase
[nix-shell]$ ./outputs/out/bin/nix --version
```

--------------------------------

### Install nix-serve

Source: https://github.com/nixos/nix/blob/master/doc/manual/source/package-management/binary-cache-substituter.md

Installs the `nix-serve` daemon from Nixpkgs. This is the first step to setting up a custom binary cache.

```console
$ nix-env --install --attr nixpkgs.nix-serve
```

--------------------------------

### Get store derivation info

Source: https://github.com/nixos/nix/blob/master/doc/manual/source/release-notes/rl-2.15.md

Example of how to get information about a store derivation itself.

```shell
nix path-info /nix/store/fpq78s2h8ffh66v2iy0q1838mhff06y8-glibc-2.33-78.drv
```

--------------------------------

### Copying a Store Path to a Remote Machine

Source: https://github.com/nixos/nix/blob/master/doc/manual/source/command-ref/nix-copy-closure.md

This example demonstrates how to copy a specific store path, representing a Nix package (GNU Hello in this case) and its dependencies, to a remote machine named 'itchy.example.org' under the user 'alice'. It first builds the package to get its store path and then uses nix-copy-closure to transfer it.

```shell
$ storePath="$(nix-build '<nixpkgs>' -I nixpkgs=channel:nixpkgs-unstable -A hello --no-out-link)"
$ nix-copy-closure --to alice@itchy.example.org "$storePath"
copying 5 paths...
copying path '/nix/store/h6q8sqsqfbd3252f9gixqn3z282wds7m-xgcc-13.2.0-libgcc' to 'ssh://alice@itchy.example.org'...
copying path '/nix/store/imnwvn96lw355giswsk36hx105j4wnpj-libunistring-1.1' to 'ssh://alice@itchy.example.org'...
copying path '/nix/store/85301indj7scg34spnfczkz72jgv8wa9-libidn2-2.3.7' to 'ssh://alice@itchy.example.org'...
copying path '/nix/store/ypwfsaljwhzw9iffiysxmxnhjj8v7np0-glibc-2.39-31' to 'ssh://alice@itchy.example.org'...
copying path '/nix/store/0dklv59zppdsqdvgf0qdvjgzcs5wbwxa-hello-2.12.1' to 'ssh://alice@itchy.example.org'...
```

--------------------------------

### Show Nix Installer Help

Source: https://github.com/nixos/nix/blob/master/doc/manual/source/installation/installing-binary.md

Displays the available command-line flags and options for the Nix installer script. Useful for customizing the installation process.

```console
$ curl -L https://nixos.org/nix/install | sh -s -- --help
```

--------------------------------

### Example nix-cache-info File

Source: https://github.com/nixos/nix/blob/master/doc/manual/source/protocols/binary-cache/nix-cache-info.md

This example shows the typical fields and their values in a nix-cache-info file.

```text
StoreDir: /nix/store
WantMassQuery: 1
Priority: 30
```

--------------------------------

### Install Nix with Rust Installer (Beta)

Source: https://github.com/nixos/nix/blob/master/doc/manual/source/release-notes/rl-2.34.md

Use this command to install Nix using the new Rust-based installer. It can be run alongside existing installations.

```bash
curl -sSfL https://artifacts.nixos.org/nix-installer | sh -s -- install
```

--------------------------------

### Install Nix on Single-User (All Platforms)

Source: https://github.com/nixos/nix/blob/master/doc/manual/source/installation/upgrading.md

Installs the Nix package and cacert for a single-user setup across all platforms using the unstable channel.

```console
$ nix-env --install --file '<nixpkgs>' --attr nix cacert -I nixpkgs=channel:nixpkgs-unstable
```

--------------------------------

### Install from a store output path

Source: https://github.com/nixos/nix/blob/master/doc/manual/source/command-ref/nix-env/install.md

Installs a package directly from its Nix store output path.

```console
$ nix-env --install /nix/store/y3cgx0xj1p4iv9x0pnnmdhr8iyg741vk-gcc-3.4.3
```

--------------------------------

### Get store derivation output paths info

Source: https://github.com/nixos/nix/blob/master/doc/manual/source/release-notes/rl-2.15.md

Example of how to get information about the output paths of a store derivation using the new '^' syntax.

```shell
nix path-info /nix/store/fpq78s2h8ffh66v2iy0q1838mhff06y8-glibc-2.33-78.drv^*
```

--------------------------------

### Simple Store Path Example

Source: https://github.com/nixos/nix/blob/master/doc/manual/source/protocols/json/store-path.md

An example of a simple Nix store path in JSON format.

```json
{
  "path": "/nix/store/abcdefghijklmnopqrstuvwxyz-example-package-1.0"
}
```

--------------------------------

### Install Nix from Binary Tarball

Source: https://github.com/nixos/nix/blob/master/doc/manual/source/installation/installing-binary.md

Installs Nix by downloading, unpacking, and running an installer from a binary tarball. This method offers more control and is useful for specific system types or offline installations. Ensure you select the correct version and system type.

```console
$ pushd $(mktemp -d)
$ export VERSION=2.19.2
$ export SYSTEM=x86_64-linux
$ curl -LO https://releases.nixos.org/nix/nix-$VERSION/nix-$VERSION-$SYSTEM.tar.xz
$ tar xfj nix-$VERSION-$SYSTEM.tar.xz
$ cd nix-$VERSION-$SYSTEM
$ ./install
$ popd
```

--------------------------------

### Example `manifest.json` Structure

Source: https://github.com/nixos/nix/blob/master/doc/manual/source/command-ref/files/manifest.json.md

This JSON structure illustrates the typical content of a `manifest.json` file, showing details of an installed package like its attribute path, original installation URI, and store path.

```json
{
  "version": 1,
  "elements": [
    {
      "active": true,
      "attrPath": "legacyPackages.x86_64-linux.zoom-us",
      "originalUrl": "flake:nixpkgs",
      "storePaths": [
        "/nix/store/wbhg2ga8f3h87s9h5k0slxk0m81m4cxl-zoom-us-5.3.469451.0927"
      ],
      "uri": "github:NixOS/nixpkgs/13d0c311e3ae923a00f734b43fd1d35b47d8943a"
    },
    …
  ]
}
```

--------------------------------

### Install Derivation from Nix Expression (All Outputs)

Source: https://github.com/nixos/nix/blob/master/doc/manual/source/command-ref/nix-env/install.md

Installs a derivation defined in a Nix expression file. By default, all outputs of the derivation are installed into the user profile.

```console
nix-env --install --file example.nix
```

--------------------------------

### Nix Bundler Configuration Example

Source: https://github.com/nixos/nix/blob/master/src/nix/bundle.md

An example of a Nix function defining bundlers for a specific system.

```nix
bundlers.x86_64-linux = rec {
  identity = drv: drv;

  blender_2_79 = drv: self.packages.x86_64-linux.blender_2_79;

  default = identity;
};

```

--------------------------------

### Install Nix in Development Shell

Source: https://github.com/nixos/nix/blob/master/doc/manual/source/development/building.md

Install Nix to the specified output directory and verify the version after building and testing.

```console
[nix-shell]$ installPhase
[nix-shell]$ nix --version
```

--------------------------------

### Start Shell with youtube-dl

Source: https://github.com/nixos/nix/blob/master/src/nix/shell.md

Starts a shell environment that includes the `youtube-dl` package from the `nixpkgs` flake. Useful for immediately using the provided tool.

```console
# nix shell nixpkgs#youtube-dl
# youtube-dl --version
2020.11.01.1
```

--------------------------------

### Install from a store derivation path

Source: https://github.com/nixos/nix/blob/master/doc/manual/source/command-ref/nix-env/install.md

Installs a package directly from its Nix store derivation path (e.g., created by `nix-instantiate`).

```console
$ nix-env --install /nix/store/8la6y31fmm6i4wfmby6avly1wf718xnj-gcc-3.4.3.drv
```

--------------------------------

### Install Nix using Binary Tarball

Source: https://github.com/nixos/nix/blob/master/doc/manual/source/release-notes/rl-1.7.md

Installs Nix by downloading and executing a bash script from a URL. This is a convenient way to install Nix on systems where binary packages are available.

```bash
$ bash <(curl -L https://nixos.org/nix/install)
```

--------------------------------

### Start nix-serve Daemon

Source: https://github.com/nixos/nix/blob/master/doc/manual/source/package-management/binary-cache-substituter.md

Starts the `nix-serve` daemon, making the Nix store available over HTTP on the specified port. Ensure the port is not already in use.

```console
$ nix-serve -p 8080
```

--------------------------------

### Start Shell with Package Names

Source: https://github.com/nixos/nix/blob/master/doc/manual/source/command-ref/nix-shell.md

A shorter way to start an interactive shell with specified packages using the --packages flag.

```console
$ nix-shell --packages sqlite xorg.libX11
[nix-shell]$ echo $NIX_LDFLAGS
… -L/nix/store/j1zg5v…-sqlite-3.8.0.2/lib -L/nix/store/0gmcz9…-libX11-1.6.1/lib …
```

--------------------------------

### Start Shell with GNU Hello from NixOS 20.03

Source: https://github.com/nixos/nix/blob/master/src/nix/shell.md

Starts a shell environment providing the GNU Hello package from a specific older version of NixOS (20.03).

```console
# nix shell nixpkgs/nixos-20.03#hello
```

--------------------------------

### Install all derivations from a Nix file

Source: https://github.com/nixos/nix/blob/master/doc/manual/source/command-ref/nix-env/install.md

Installs all derivations defined within a specified Nix expression file.

```console
$ nix-env --file ~/foo.nix --install '.*'
```

--------------------------------

### Install Built Store Path Directly

Source: https://github.com/nixos/nix/blob/master/doc/manual/source/release-notes/rl-0.8.md

Install a package by directly referencing an already built store path.

```bash
$ nix-env -i /nix/store/hsyj5pbn0d9i...-aterm-2.3.1
```

--------------------------------

### Start Nix Daemon

Source: https://github.com/nixos/nix/blob/master/doc/manual/source/installation/multi-user.md

Starts the Nix daemon. This command should be added to system boot scripts to ensure the daemon runs on startup.

```bash
$ nix-daemon
```

--------------------------------

### Bundle Hello World

Source: https://github.com/nixos/nix/blob/master/src/nix/bundle.md

Bundles the 'nixpkgs#hello' installable and executes it.

```console
# nix bundle nixpkgs#hello
# ./hello
Hello, world!
```

--------------------------------

### Install Package from Tarball URL with nix-env

Source: https://github.com/nixos/nix/blob/master/doc/manual/source/release-notes/rl-1.9.md

Use nix-env to install a package by specifying the URL of a tarball containing Nix expressions. This example installs Firefox from a specific Nixpkgs channel archive.

```bash
$ nix-env -f https://github.com/NixOS/nixpkgs-channels/archive/nixos-14.12.tar.gz -iA firefox
```

--------------------------------

### Basic Lookup Path Example

Source: https://github.com/nixos/nix/blob/master/doc/manual/source/language/constructs/lookup-path.md

Demonstrates a simple lookup path `<nixpkgs>` which resolves to a specific path.

```nix
<nixpkgs>
```

--------------------------------

### Install package by name (arbitrary version)

Source: https://github.com/nixos/nix/blob/master/doc/manual/source/command-ref/nix-env/install.md

Installs a package by its general name, allowing Nix to select a version (often the latest available).

```console
$ nix-env --install gcc
installing `gcc-3.3.2'
```

--------------------------------

### Getting JSON Output for Installed Packages

Source: https://github.com/nixos/nix/blob/master/doc/manual/source/release-notes/rl-1.7.md

Demonstrates the --json flag for `nix-env -q` to obtain a JSON representation of installed or available packages.

```bash
nix-env -q --json
```

--------------------------------

### Next Steps After Project Initialization

Source: https://github.com/nixos/nix/blob/master/doc/manual/source/development/cli-guideline.md

Provides guidance on the usual development workflow with Nix after initializing a new project.

```shell
$ nix init --template=template#python
Initializing project `template#python`
          in `/home/USER/dev/new-project`

  Next steps
    |> nix develop   -- to enter development environment
    |> nix build     -- to build your project
```

--------------------------------

### Install Nix on Linux Multi-User

Source: https://github.com/nixos/nix/blob/master/doc/manual/source/installation/upgrading.md

Installs the Nix package and cacert on a Linux system with a multi-user setup using the unstable channel. Requires root privileges.

```console
$ sudo su
# nix-env --install --file '<nixpkgs>' --attr nix cacert -I nixpkgs=channel:nixpkgs-unstable
# systemctl daemon-reload
# systemctl restart nix-daemon
```

--------------------------------

### Bundle Hello with Docker Image Bundler

Source: https://github.com/nixos/nix/blob/master/src/nix/bundle.md

Bundles 'nixpkgs#hello' using the 'toDockerImage' bundler, loads it into Docker, and runs it.

```console
# nix bundle --bundler github:NixOS/bundlers#toDockerImage nixpkgs#hello
# docker load < hello-2.10.tar.gz
# docker run hello-2.10:latest hello
Hello, world!
```

--------------------------------

### Build and Print Output Paths

Source: https://github.com/nixos/nix/blob/master/src/nix/build.md

Builds the 'hello' package from 'nixpkgs' and prints the resulting store path to standard output. Useful for scripting and automation.

```console
# nix build nixpkgs#hello --print-out-paths
/nix/store/10l19qifk7hjjq47px8m2prqk1gv4isy-hello-2.10
```

--------------------------------

### Path Flake Reference Examples

Source: https://github.com/nixos/nix/blob/master/src/nix/flake.md

Examples of path-based flake references for local directories. The 'path:' prefix is optional for absolute paths not in a git repository, and for relative paths starting with './'.

```nix
path:/home/user/sub/dir

```

```nix
/home/user/sub/dir

```

```nix
path:sub/dir

```

```nix
./sub/dir

```

```nix
path:../parent

```

--------------------------------

### Simple Build Trace Entry Example

Source: https://github.com/nixos/nix/blob/master/doc/manual/source/protocols/json/build-trace-entry.md

A basic example of a build trace entry in JSON format. This serves as a fundamental structure for recording build events.

```json
{
  "outputs": {
    "out": {
      "path": "/nix/store/s4z4f7z4f7z4f7z4f7z4f7z4f7z4f7z4-hello-2.10",
      "hashAlgo": "sha256",
      "hash": "1111111111111111111111111111111111111111111111111111"
    }
  },
  "inputDrvs": {
    "/nix/store/xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx-hello-2.10.drv": "/nix/store/s4z4f7z4f7z4f7z4f7z4f7z4f7z4f7z4-hello-2.10"
  },
  "logs": {},
  "time": 1678886400,
  "duration": 1000,
  "successful": true,
  "name": "hello-2.10",
  "system": "x86_64-linux",
  "path": "/nix/store/s4z4f7z4f7z4f7z4f7z4f7z4f7z4f7z4-hello-2.10"
}
```

--------------------------------

### Copying a Store Path from a Remote Machine and Running It

Source: https://github.com/nixos/nix/blob/master/doc/manual/source/command-ref/nix-copy-closure.md

This example shows how to retrieve a specific store path (GNU Hello's output path) from a remote machine ('itchy.example.org' as user 'alice') to the local machine. After copying, it demonstrates how to execute the program located at the retrieved store path.

```shell
$ storePath="$(nix-instantiate --eval --raw '<nixpkgs>' -I nixpkgs=channel:nixpkgs-unstable -A hello.outPath)"
$ nix-copy-closure --from alice@itchy.example.org "$storePath"
$ "$storePath"/bin/hello
Hello, world!
```

--------------------------------

### Install Nix on macOS Multi-User

Source: https://github.com/nixos/nix/blob/master/doc/manual/source/installation/upgrading.md

Installs the Nix package and cacert on a macOS system with a multi-user setup using the unstable channel. Requires root privileges and involves managing the Nix daemon service.

```console
$ sudo nix-env --install --file '<nixpkgs>' --attr nix cacert -I nixpkgs=channel:nixpkgs-unstable
$ sudo launchctl remove org.nixos.nix-daemon
$ sudo launchctl load /Library/LaunchDaemons/org.nixos.nix-daemon.plist
```

--------------------------------

### Example Include Path in Nix Store

Source: https://github.com/nixos/nix/blob/master/doc/manual/source/introduction.md

Shows how include paths for packages are stored in the Nix store, demonstrating explicit dependency management.

```text
/nix/store/5lbfaxb722zp…-openssl-0.9.8d/include
```

--------------------------------

### Nix Block Comment Example

Source: https://github.com/nixos/nix/blob/master/doc/manual/source/language/syntax.md

Block comments start with '/*' and end with '*/', allowing multi-line comments. They cannot be nested.

```nix
/*
Block comments
can span multiple lines.
*/ "hello"
```

--------------------------------

### Nix Inline Comment Example

Source: https://github.com/nixos/nix/blob/master/doc/manual/source/language/syntax.md

Inline comments start with '#' and extend to the end of the line. They can be used to add brief explanations within code.

```nix
# A number
2 # Equals 1 + 1
```

--------------------------------

### Setting up a Shell Environment with Specified Packages

Source: https://github.com/nixos/nix/blob/master/doc/manual/source/release-notes/rl-1.7.md

Shows how to use the --packages flag with nix-shell to create a shell environment that includes specific packages from Nixpkgs.

```bash
$ nix-shell -p sqlite xorg.libX11 hello
```

--------------------------------

### Nix Profile Version Contents Example

Source: https://github.com/nixos/nix/blob/master/src/nix/profiles.md

Shows the contents of a specific Nix profile version, detailing the symlinks to installed packages in the bin and share directories.

```console
$ ll -R ~eelco/.local/state/nix/profiles/profile-7-link/
/home/eelco/.local/state/nix/profiles/profile-7-link/:
total 20
dr-xr-xr-x 2 root root 4096 Jan  1  1970 bin
-r--r--r-- 2 root root 1402 Jan  1  1970 manifest.nix
dr-xr-xr-x 4 root root 4096 Jan  1  1970 share

/home/eelco/.local/state/nix/profiles/profile-7-link/bin:
total 20
lrwxrwxrwx 5 root root 79 Jan  1  1970 chromium -> /nix/store/cyxny9d1zjb9l9103fr6j6kavp3bqjxf-chromium-86.0.4240.111/bin/chromium
lrwxrwxrwx 7 root root 87 Jan  1  1970 spotify -> /nix/store/w9182874m1bl56smps3m5zjj36jhp3rn-spotify-1.1.26.501.gbe11e53b-15/bin/spotify
lrwxrwxrwx 3 root root 79 Jan  1  1970 zoom-us -> /nix/store/wbhg2ga8f3h87s9h5k0slxk0m81m4cxl-zoom-us-5.3.469451.0927/bin/zoom-us

/home/eelco/.local/state/nix/profiles/profile-7-link/share/applications:
total 12
lrwxrwxrwx 4 root root 120 Jan  1  1970 chromium-browser.desktop -> /nix/store/sqzyx2l85i6j2a77pnyvglh3bvzwmjjp-chromium-unwrapped-86.0.4240.111/share/applications/chromium-browser.desktop
lrwxrwxrwx 7 root root 110 Jan  1  1970 spotify.desktop -> /nix/store/w9182874m1bl56smps3m5zjj36jhp3rn-spotify-1.1.26.501.gbe11e53b-15/share/applications/spotify.desktop
lrwxrwxrwx 3 root root 107 Jan  1  1970 us.zoom.Zoom.desktop -> /nix/store/wbhg2ga8f3h87s9h5k0slxk0m81m4cxl-zoom-us-5.3.469451.0927/share/applications/us.zoom.Zoom.desktop
```

--------------------------------

### New Build Trace Key Example

Source: https://github.com/nixos/nix/blob/master/doc/manual/rl-next/build-trace-rework.md

Shows the new format for build trace keys, using the regular derivation store path and output name.

```text
/nix/store/abc...-foo.drv^out
```

--------------------------------

### Nix Build Command Example

Source: https://github.com/nixos/nix/blob/master/doc/manual/source/development/cli-guideline.md

Demonstrates the expected output for a Nix build command, showing download progress and a success message. This output clearly indicates command completion.

```shell
$ nix build
 Downloaded python3.8-poetry 1.2.3 in 5.3 seconds
 Downloaded python3.8-requests 1.2.3 in 5.3 seconds
...
   Success! You have successfully built my-project.
$
```

--------------------------------

### Defining a shellHook in Nix

Source: https://github.com/nixos/nix/blob/master/doc/manual/source/command-ref/nix-shell.md

This example shows how to define a shellHook in a Nix derivation. The hook runs after environment setup and can be used for initialization tasks like setting environment variables.

```nix
shellHook =
  ''
    echo "Hello shell"
    export SOME_API_TOKEN="$(cat ~/.config/some-app/api-token)"
  '';
```

--------------------------------

### Download a file and get SHA-512 hash

Source: https://github.com/nixos/nix/blob/master/src/nix/store-prefetch-file.md

This example demonstrates how to download a file, specify SHA-512 as the hash type, and extract only the hash value using 'jq'. This is useful for scripting and automation.

```console
# nix store prefetch-file --json --hash-type sha512 \
    https://releases.nixos.org/nix/nix-2.3.10/nix-2.3.10.tar.xz \
  | jq -r .hash
sha512-6XJxfym0TNH9knxeH4ZOvns6wElFy3uahunl2hJgovACCMEMXSy42s69zWVyGJALXTI+86tpDJGlIcAySEKBbA==
```

--------------------------------

### Build Nix Manual from Scratch

Source: https://github.com/nixos/nix/blob/master/doc/manual/source/development/documentation.md

Use this command to perform a full build of the Nix manual. The output can be found in the specified path.

```console
nix-build -E '(import ./.).packages.${builtins.currentSystem}.nix.doc'
```

--------------------------------

### Use Tarball URL in Nix Path

Source: https://github.com/nixos/nix/blob/master/doc/manual/source/release-notes/rl-1.9.md

Specify a tarball URL in the Nix path (NIX_PATH or -I) to use a specific version of Nixpkgs. This example starts a shell with the Pan package from a specific Nixpkgs commit.

```bash
$ nix-shell -p pan -I nixpkgs=https://github.com/NixOS/nixpkgs-channels/archive/8a3eea054838b55aca962c3fbde9c83c102b8bf2.tar.gz
```

--------------------------------

### Modifying package meta attributes with nix-env --set-flag

Source: https://github.com/nixos/nix/blob/master/doc/manual/source/release-notes/rl-0.11.md

Use `nix-env --set-flag` to modify meta attributes of installed packages. This is useful for adjusting `meta.priority`, `meta.keep`, or `meta.active` to control package behavior and environment setup.

```bash
nix-env --set-flag meta.keep true <package>
```

```bash
nix-env --set-flag meta.active false <package>
```

--------------------------------

### Nix Store Path Example

Source: https://github.com/nixos/nix/blob/master/doc/manual/source/store/store-path.md

Illustrates the components of a typical Nix store path, showing the store directory, digest, and name.

```text
  /nix/store/q06x3jll2yfzckz2bzqak089p43ixkkq-firefox-33.1
  |--------| |------------------------------| |----------|
  store directory            digest                 name
```

--------------------------------

### Using the basic fetchurl function

Source: https://github.com/nixos/nix/blob/master/doc/manual/source/release-notes/rl-1.1.md

This snippet demonstrates how to use the basic `fetchurl` function for bootstrapping purposes. It requires the URL and a SHA256 hash of the content.

```nix
import <nix/fetchurl.nix> { url = url; sha256 = "hash"; }
```

--------------------------------

### Uninstall Nix with Rust Installer

Source: https://github.com/nixos/nix/blob/master/doc/manual/source/release-notes/rl-2.34.md

Use this command to uninstall Nix if it was installed using the new Rust-based installer. This will remove the entire Nix installation.

```bash
/nix/nix-installer uninstall
```

--------------------------------

### Markdown Admonition Example (Example)

Source: https://github.com/nixos/nix/blob/master/doc/manual/source/development/documentation.md

Illustrates the markdown format for highlighting code examples within documentation using the 'Example' admonition type and a console code block.

```markdown
> **Example**
> 
> ```console
> $ nix --version
> ```
```

--------------------------------

### Compile and Run Nix Evaluator Example

Source: https://github.com/nixos/nix/blob/master/src/external-api-docs/README.md

Demonstrates how to compile the C code using pkg-config and execute the program to display the Nix version.

```ShellSession
$ gcc main.c $(pkg-config nix-expr-c --libs --cflags) -o main
$ ./main
Nix version: 2.17
```

--------------------------------

### Install Latest Nix Binary

Source: https://github.com/nixos/nix/blob/master/doc/manual/source/installation/installing-binary.md

Installs the latest stable version of Nix using the default installation script. This is the recommended method for most users.

```console
$ curl -L https://nixos.org/nix/install | sh
```

--------------------------------

### Simple Nix Flake Example

Source: https://github.com/nixos/nix/blob/master/src/nix/flake.md

This example demonstrates a basic flake.nix file that defines a single package. It depends on the Nixpkgs flake and uses `stdenv.mkDerivation` to build a 'hello' program.

```nix
{ 
  description = "A flake for building Hello World";

  inputs.nixpkgs.url = "github:NixOS/nixpkgs/nixos-20.03";

  outputs = { self, nixpkgs }:
    { 

    packages.x86_64-linux.default =
      # Notice the reference to nixpkgs here.
      with import nixpkgs { system = "x86_64-linux"; };
      stdenv.mkDerivation {
        name = "hello";
        src = self;
        buildPhase = "gcc -o hello ./hello.c";
        installPhase = "mkdir -p $out/bin; install -t $out/bin hello";
      };

  };
}

```

--------------------------------

### Install Nix (Single-user)

Source: https://github.com/nixos/nix/blob/master/doc/manual/source/installation/index.md

Install Nix using the single-user option, suitable for systems without systemd. Note that installing as root is not supported by this script.

```bash
$ curl -L https://nixos.org/nix/install | sh -s -- --no-daemon
```

--------------------------------

### Nix Store Derivation Path Example

Source: https://github.com/nixos/nix/blob/master/src/nix/nix.md

Represents a derivation file, which defines how to build a package.

```text
/nix/store/p7gp6lxdg32h4ka1q398wd9r2zkbbz2v-hello-2.10.drv
```

--------------------------------

### Generate Install Command with Artifact

Source: https://github.com/nixos/nix/blob/master/doc/manual/source/development/testing.md

Use this command template to generate an install command by providing the path to the unpacked installer artifact. This is useful for manual testing after CI runs.

```bash
sh <path/to/artifact>/install --tarball-url-prefix file://<path/to/artifact>
```

--------------------------------

### Start Shell with Overridden Package

Source: https://github.com/nixos/nix/blob/master/doc/manual/source/command-ref/nix-shell.md

Demonstrates using the --packages flag with a Nix expression override, allowing for customized package configurations.

```console
$ nix-shell --packages sqlite 'git.override { withManual = false; }'
```

--------------------------------

### Instantiate and Build a Nix Derivation

Source: https://github.com/nixos/nix/blob/master/doc/manual/source/command-ref/nix-instantiate.md

Instantiates a Nix derivation from a file and then builds it using nix-store. Shows the resulting store path.

```console
$ nix-instantiate test.nix (instantiate)
/nix/store/cigxbmvy6dzix98dxxh9b6shg7ar5bvs-perl-BerkeleyDB-0.26.drv

$ nix-store --realise $(nix-instantiate test.nix) (build)
... 
/nix/store/qhqk4n8ci095g3sdp93x7rgwyh9rdvgk-perl-BerkeleyDB-0.26 (output path)

$ ls -l /nix/store/qhqk4n8ci095g3sdp93x7rgwyh9rdvgk-perl-BerkeleyDB-0.26
dr-xr-xr-x    2 eelco    users        4096 1970-01-01 01:00 lib
...
```

--------------------------------

### Install package by derivation name

Source: https://github.com/nixos/nix/blob/master/doc/manual/source/command-ref/nix-env/install.md

Installs a specific version of a package using its derivation name. Note that if `--preserve-installed` is not used, previously installed versions may be removed.

```console
$ nix-env --install gcc-3.3.2
installing `gcc-3.3.2'
uninstalling `gcc-3.1'
```

--------------------------------

### Nix Profile Filesystem Layout Example

Source: https://github.com/nixos/nix/blob/master/src/nix/profiles.md

Illustrates the symlink structure of Nix profiles, showing how a profile link points to a versioned link, which in turn points to a Nix store path.

```console
$ ls -l ~alice/.local/state/nix/profiles/profile*
lrwxrwxrwx 1 alice users 14 Nov 25 14:35 /home/alice/.local/state/nix/profiles/profile -> profile-7-link
lrwxrwxrwx 1 alice users 51 Oct 28 16:18 /home/alice/.local/state/nix/profiles/profile-5-link -> /nix/store/q69xad13ghpf7ir87h0b2gd28lafjj1j-profile
lrwxrwxrwx 1 alice users 51 Oct 29 13:20 /home/alice/.local/state/nix/profiles/profile-6-link -> /nix/store/6bvhpysd7vwz7k3b0pndn7ifi5xr32dg-profile
lrwxrwxrwx 1 alice users 51 Nov 25 14:35 /home/alice/.local/state/nix/profiles/profile-7-link -> /nix/store/mp0x6xnsg0b8qhswy6riqvimai4gm677-profile
```

--------------------------------

### Force Multi-User Nix Installation

Source: https://github.com/nixos/nix/blob/master/doc/manual/source/installation/installing-binary.md

Explicitly instructs the installer to perform a multi-user installation, which is recommended for Linux systems with systemd and without SELinux, and for macOS. The script handles sudo invocation.

```console
$ bash <(curl -L https://nixos.org/nix/install) --daemon
```

--------------------------------

### Install Pinned Nix Version

Source: https://github.com/nixos/nix/blob/master/doc/manual/source/installation/installing-binary.md

Installs a specific version of Nix by setting the VERSION environment variable and then running the install script from a version-specific URL. Ensure the specified version is available on releases.nixos.org.

```console
$ export VERSION=2.19.2 
$ curl -L https://releases.nixos.org/nix/nix-$VERSION/install | sh
```

--------------------------------

### Install a Package using nix-env

Source: https://github.com/nixos/nix/blob/master/doc/manual/source/package-management/profiles.md

Installs a specific package from Nix expressions into the user environment.

```console
$ nix-env --install --attr nixpkgs.subversion
```

--------------------------------

### Viewing nix-env Operation Help

Source: https://github.com/nixos/nix/blob/master/doc/manual/source/command-ref/nix-env.md

Demonstrates how to view help for specific nix-env operations, either via man pages or the --help flag.

```bash
man nix-env-install
```

```bash
nix-env --help --install
```

--------------------------------

### Shell Completion Example

Source: https://github.com/nixos/nix/blob/master/doc/manual/source/development/cli-guideline.md

Demonstrates context-aware shell completion for Nix commands, suggesting relevant flakes based on user input.

```shell
$ nix build n<TAB>
```

--------------------------------

### Manually Create /nix for Single-User Install

Source: https://github.com/nixos/nix/blob/master/doc/manual/source/installation/installing-binary.md

Provides manual steps to create the /nix directory and set ownership for a single-user installation if sudo is not available. This is a fallback for environments where sudo cannot be used.

```console
$ su root
# mkdir /nix
# chown alice /nix
```

--------------------------------

### Mounting Nix Store with Bind Mount

Source: https://github.com/nixos/nix/blob/master/doc/manual/source/command-ref/env-common.md

Example of how to use bind mount points on Linux to place the Nix store on a different file system. This is a recommended alternative to symlinking the Nix store directory.

```bash
$ mkdir /nix
$ mount -o bind /mnt/otherdisk/nix /nix
```

--------------------------------

### Install Pre-commit Hooks

Source: https://github.com/nixos/nix/blob/master/HACKING.md

Install pre-commit hooks to automatically run formatters before each commit. This uses cachix/git-hooks.nix.

```shell
pre-commit-hooks-install
```

--------------------------------

### Install GDB Debugger

Source: https://github.com/nixos/nix/blob/master/doc/manual/source/development/debugging.md

Install the GNU Debugger (GDB) within the development shell for debugging Nix.

```console
[nix-shell]$ nix-shell -p gdb
```

--------------------------------

### Configure and Build Nix

Source: https://github.com/nixos/nix/blob/master/HACKING.md

Set up build variables and execute the configure and build phases within the development shell. The output will be placed in $(pwd)/outputs/out.

```console
[nix-shell]$ out="$(pwd)/outputs/out" dev=$out debug=$out mesonFlags+=" --prefix=${out}"
[nix-shell]$ dontAddPrefix=1 configurePhase
[nix-shell]$ buildPhase
```

--------------------------------

### Build Package Using Nix Path

Source: https://github.com/nixos/nix/blob/master/doc/manual/source/release-notes/rl-2.4.md

Alternatively, use the '-f "<nixpkgs>"' option with the 'hello' package if 'nixpkgs' is in your NIX_PATH environment variable.

```console
nix build -f '<nixpkgs>' hello
```

--------------------------------

### Example Protocol: Store Paths

Source: https://github.com/nixos/nix/blob/master/src/nix/unix/store-roots-daemon.md

This example illustrates the protocol used by the roots daemon. The server sends zero or more store paths, each terminated by a NUL character (`\0`). The example shows these paths with newlines for clarity, but they are NUL-delimited in actual communication.

```text
/nix/store/s66mzxpvicwk07gjbjfw9izjfa797vsw-hello-2.12.1
/nix/store/fvpr7x8l3illdnziggvkhdpf6vikg65w-git-2.44.0
```

--------------------------------

### Enter Nix Build Environment

Source: https://github.com/nixos/nix/blob/master/doc/manual/source/introduction.md

Use `nix-shell` to automatically set up the build environment for a package. This command builds or downloads dependencies and starts a shell with necessary environment variables set.

```console
$ nix-shell '<nixpkgs>' --attr pan
```

--------------------------------

### Print Store Path of an Installable

Source: https://github.com/nixos/nix/blob/master/src/nix/path-info.md

Use this to display the Nix store path for a given installable, such as a package from nixpkgs.

```console
# nix path-info nixpkgs#hello
/nix/store/10l19qifk7hjjq47px8m2prqk1gv4isy-hello-2.10
```

--------------------------------

### Load Nix Expressions from File

Source: https://github.com/nixos/nix/blob/master/src/nix/repl.md

Start the Nix REPL with a specific Nix expression file loaded.

```console
nix repl --file example.nix
Loading Installable ''...
Added 3 variables.
```

--------------------------------

### Install Multiple Packages using nix-env

Source: https://github.com/nixos/nix/blob/master/doc/manual/source/package-management/profiles.md

Installs multiple packages, creating a new generation of the user environment.

```console
$ nix-env --install --attr nixpkgs.subversion nixpkgs.firefox
```

--------------------------------

### Package Version and Size Change Example

Source: https://github.com/nixos/nix/blob/master/src/nix/diff-closures.md

Illustrates the output format for a package with a version change and a size difference exceeding the threshold.

```console
dolphin: 20.08.1 → 20.08.2, +13.9 KiB
```

--------------------------------

### Build and Run Package from Nixpkgs Flake

Source: https://github.com/nixos/nix/blob/master/src/nix/build.md

Builds the 'hello' package from the 'nixpkgs' flake and then runs the resulting executable. Demonstrates building a specific package from a remote flake.

```console
# nix build nixpkgs#hello
# ./result/bin/hello
```

--------------------------------

### Build C API Documentation

Source: https://github.com/nixos/nix/blob/master/doc/manual/source/development/documentation.md

Builds the C API documentation using `nix build` and opens the generated HTML files.

```console
$ nix build .#hydraJobs.external-api-docs
$ xdg-open ./result/share/doc/nix/external-api/html/index.html
```

--------------------------------

### Install LLDB Debugger on macOS

Source: https://github.com/nixos/nix/blob/master/doc/manual/source/development/debugging.md

Install the LLDB debugger within the development shell on macOS for debugging Nix.

```console
[nix-shell]$ nix-shell -p lldb
```

--------------------------------

### Indirect Flake Reference Examples

Source: https://github.com/nixos/nix/blob/master/src/nix/flake.md

Examples of indirect flake references, which are symbolic references looked up in flake registries.

```nix
nixpkgs

```

```nix
nixpkgs/nixos-unstable

```

```nix
nixpkgs/a3a3dda3bacf61e8a39258a0ed9c924eeca8e293

```

```nix
nixpkgs/nixos-unstable/a3a3dda3bacf61e8a39258a0ed9c924eeca8e293

```

```nix
sub/dir

```

--------------------------------

### Install Store Derivation Directly

Source: https://github.com/nixos/nix/blob/master/doc/manual/source/release-notes/rl-0.8.md

Install a package by directly referencing its derivation file, bypassing the Nix expression language.

```bash
$ nix-env -i /nix/store/z58v41v21xd3...-aterm-2.3.1.drv
```

--------------------------------

### Show all paths from Thunderbird to libX11

Source: https://github.com/nixos/nix/blob/master/src/nix/why-depends.md

Use the `--all` flag to list all dependency paths and the files containing references from 'thunderbird' to 'xorg.libX11'. This can reveal multiple reasons for a dependency.

```console
# nix why-depends --all nixpkgs#thunderbird nixpkgs#xorg.libX11
/nix/store/0my2p7psgdzqc5pq6dyl4ld9w6g0np58-thunderbird-78.5.1
├───lib/thunderbird/libxul.so: …6wrw-libxcb-1.14/lib:/nix/store/jmwiq1bb3n47a0css8b1q7lhgf7416k5-libX11-1.7.0/lib:/nix/store/ssf…
│   → /nix/store/jmwiq1bb3n47a0css8b1q7lhgf7416k5-libX11-1.7.0
├───lib/thunderbird/libxul.so: …pxyc-libXt-1.2.0/lib:/nix/store/l1sv43bafhkf2iikmdw9y62aybjdhcmm-libXdamage-1.1.5/lib:/nix/store…
│   → /nix/store/l1sv43bafhkf2iikmdw9y62aybjdhcmm-libXdamage-1.1.5
│   ├───lib/libXdamage.so.1.1.0: …-libXfixes-5.0.3/lib:/nix/store/jmwiq1bb3n47a0css8b1q7lhgf7416k5-libX11-1.7.0/lib:/nix/store/9l0…
│   │   → /nix/store/jmwiq1bb3n47a0css8b1q7lhgf7416k5-libX11-1.7.0
…

```

--------------------------------

### Running a Package with a Custom Store Path

Source: https://github.com/nixos/nix/blob/master/doc/manual/source/release-notes/rl-2.0.md

This command downloads or builds the GNU Hello package into a specified local store path and then runs the `hello` executable within a mount namespace where the custom store is mounted onto `/nix/store`.

```bash
nix run --store ~/my-nix nixpkgs.hello -c hello --greeting 'Hi everybody!'
```

--------------------------------

### Install package from a specific channel archive

Source: https://github.com/nixos/nix/blob/master/doc/manual/source/command-ref/nix-env/install.md

Installs a package from a specific revision of a channel, identified by a URL to a tarball archive.

```console
$ nix-env --file https://github.com/NixOS/nixpkgs/archive/nixos-14.12.tar.gz --install --attr firefox
```

--------------------------------

### Generate Installer Script

Source: https://github.com/nixos/nix/blob/master/doc/manual/source/development/testing.md

This command generates the installer tarball and script for a specified system. Replace <system-double> with the target system architecture.

```bash
nix build .#hydraJobs.installerScriptForGHA.<system-double>
```