Reference

nix3-print-dev-env(1)

print shell code that can be sourced by bash to reproduce the build environment of a derivation

Warning
This program is experimental ⟨@docroot@/development/experimental-features.md#xp-feature-nix-command⟩ 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 ⟨./nix.md#installables⟩\c . 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

•

--json ⟨#opt-json⟩

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

•

--profile ⟨#opt-profile⟩ path

The profile to operate on.

•

--redirect ⟨#opt-redirect⟩ installable outputs-dir

Redirect a store path to a mutable location.

Common evaluation options

•

--arg ⟨#opt-arg⟩ name expr

Pass the value expr as the argument name to Nix functions.

•

--arg-from-file ⟨#opt-arg-from-file⟩ name path

Pass the contents of file path as the argument name to Nix functions.

•

--arg-from-stdin ⟨#opt-arg-from-stdin⟩ name

Pass the contents of stdin as the argument name to Nix functions.

•

--argstr ⟨#opt-argstr⟩ name string

Pass the string string as the argument name to Nix functions.

•

--debugger ⟨#opt-debugger⟩

Start an interactive environment if evaluation fails.

•

--eval-store ⟨#opt-eval-store⟩ store-url

The URL of the Nix store ⟨@docroot@/store/types/index.md#store-url-format⟩ to use for evaluation, i.e. to store derivations (.drv files) and inputs referenced by them.

•

--impure ⟨#opt-impure⟩

Allow access to mutable paths and repositories.

•

--include ⟨#opt-include⟩ / -I path

Add path to search path entries used to resolve lookup paths ⟨@docroot@/language/constructs/lookup-path.md⟩

This option may be given multiple times.

Paths added through -I take precedence over the nix-path configuration setting ⟨@docroot@/command-ref/conf-file.md#conf-nix-path⟩ and the NIX_PATH environment variable ⟨@docroot@/command-ref/env-common.md#env-NIX_PATH⟩\c .

•

--override-flake ⟨#opt-override-flake⟩ original-ref resolved-ref

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

Common flake-related options

•

--commit-lock-file ⟨#opt-commit-lock-file⟩

Commit changes to the flake’s lock file.

•

--inputs-from ⟨#opt-inputs-from⟩ flake-url

Use the inputs of the specified flake as registry entries.

•

--no-registries ⟨#opt-no-registries⟩

Don’t allow lookups in the flake registries.

DEPRECATED

Use --no-use-registries ⟨@docroot@/command-ref/conf-file.md#conf-use-registries⟩ instead.

•

--no-update-lock-file ⟨#opt-no-update-lock-file⟩

Do not allow any updates to the flake’s lock file.

•

--no-write-lock-file ⟨#opt-no-write-lock-file⟩

Do not write the flake’s newly generated lock file.

•

--output-lock-file ⟨#opt-output-lock-file⟩ flake-lock-path

Write the given lock file instead of flake.lock within the top-level flake.

•

--override-input ⟨#opt-override-input⟩ input-path flake-url

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

•

--recreate-lock-file ⟨#opt-recreate-lock-file⟩

Recreate the flake’s lock file from scratch.

DEPRECATED

Use nix flake update ⟨@docroot@/command-ref/new-cli/nix3-flake-update.md⟩ instead.

•

--reference-lock-file ⟨#opt-reference-lock-file⟩ flake-lock-path

Read the given lock file instead of flake.lock within the top-level flake.

•

--update-input ⟨#opt-update-input⟩ input-path

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

DEPRECATED

Use nix flake update ⟨@docroot@/command-ref/new-cli/nix3-flake-update.md⟩ instead.

Logging-related options

•

--debug ⟨#opt-debug⟩

Set the logging verbosity level to ‘debug’.

•

--log-format ⟨#opt-log-format⟩ format

Set the format of log output; one of raw, internal-json, bar or bar-with-logs.

•

--print-build-logs ⟨#opt-print-build-logs⟩ / -L

Print full build logs on standard error.

•

--quiet ⟨#opt-quiet⟩

Decrease the logging verbosity level.

•

--verbose ⟨#opt-verbose⟩ / -v

Increase the logging verbosity level.

Miscellaneous global options

•

--help ⟨#opt-help⟩

Show usage information.

•

--offline ⟨#opt-offline⟩

Disable substituters and consider all previously downloaded files up-to-date.

•

--option ⟨#opt-option⟩ name value

Set the Nix configuration setting name to value (overriding nix.conf).

•

--refresh ⟨#opt-refresh⟩

Consider all previously downloaded files out-of-date.

•

--repair ⟨#opt-repair⟩

During evaluation, rewrite missing or corrupted files in the Nix store. During building, rebuild missing or corrupted store paths.

•

--version ⟨#opt-version⟩

Show version information.

Options that change the interpretation of installables

•

--expr ⟨#opt-expr⟩ expr

Interpret installables ⟨@docroot@/command-ref/new-cli/nix.md#installables⟩ as attribute paths relative to the Nix expression expr.

•

--file ⟨#opt-file⟩ / -f file

Interpret installables ⟨@docroot@/command-ref/new-cli/nix.md#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.

Note

See man nix.conf ⟨@docroot@/command-ref/conf-file.md#command-line-flags⟩ for overriding configuration settings with command line flags.

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