nix3-print-dev-env(1)

Warning: This program is experimental and its interface is subject to change.

Name
nix print-dev-env - print shell code that can be sourced by bash to reproduce the build environment of a derivation

Synopsis
nix print-dev-env [option…] installable

Examples

•   Apply the build environment of GNU hello to the current shell:

    # . <(nix print-dev-env nixpkgs#hello)

•   Get the build environment in JSON format:

    # nix print-dev-env nixpkgs#hello --json

    The output will look like this:

    {
    "bashFunctions": {
      "buildPhase": " \n    runHook preBuild;\n...",
      ...
    },
    "variables": {
      "src": {
        "type": "exported",
        "value": "/nix/store/3x7dwzq014bblazs7kq20p9hyzz0qh8g-hello-2.10.tar.gz"
      },
      "postUnpackHooks": {
        "type": "array",
        "value": ["_updateSourceDateEpochFromSourceRoot"]
      },
      ...
    }
    }

Description
This command prints a shell script that can be sourced by bash and that sets the variables and shell functions defined by the build process of installable. This allows you to get a similar build environment in your current shell rather than in a subshell (as with nix develop).

With --json, the output is a JSON serialisation of the variables and functions defined by the build process.

Options

•   --debugger
    start an interactive environment if evaluation fails

•   --json
    Produce output in JSON format, suitable for consumption by another program.

•   --profile path
    The profile to update.

•   --redirect installable outputs-dir
    Redirect a store path to a mutable location.

Common evaluation options:

•   --arg name expr
    Pass the value expr as the argument name to Nix functions.

•   --argstr name string
    Pass the string string as the argument name to Nix functions.

•   --eval-store store-url
    The Nix store to use for evaluations.

•   --impure
    Allow access to mutable paths and repositories.

•   --include / -I path
    Add path to the list of locations used to look up <...> file names.

•   --override-flake original-ref resolved-ref
    Override the flake registries, redirecting original-ref to resolved-ref.

Common flake-related options:

•   --commit-lock-file
    Commit changes to the flake’s lock file.

•   --inputs-from flake-url
    Use the inputs of the specified flake as registry entries.

•   --no-registries
    Don’t allow lookups in the flake registries. This option is deprecated; use --no-use-registries.

•   --no-update-lock-file
    Do not allow any updates to the flake’s lock file.

•   --no-write-lock-file
    Do not write the flake’s newly generated lock file.

•   --override-input input-path flake-url
    Override a specific flake input (e.g. dwarffs/nixpkgs). This implies --no-write-lock-file.

•   --recreate-lock-file
    Recreate the flake’s lock file from scratch.

•   --update-input input-path
    Update a specific flake input (ignoring its previous entry in the lock file).

Options that change the interpretation of installables:

•   --derivation
    Operate on the store derivation rather than its outputs.

•   --expr expr
    Interpret installables as attribute paths relative to the Nix expression expr.

•   --file / -f file
    Interpret installables as attribute paths relative to the Nix expression stored in file. If file is the character -, then a Nix expression will be read from standard input. Implies --impure.