nix3-print-dev-env(1) General Commands Manual nix3-print-dev-env(1)

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

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

nix print-dev-env [option…] installable

•
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"]
  },
  ...
}
}

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.

•
--json
Produce output in JSON format, suitable for consumption by another program.
•
--profile path
The profile to operate on.
•
--redirect installable outputs-dir
Redirect a store path to a mutable location.

•
--arg name expr
Pass the value expr as the argument name to Nix functions.
•
--arg-from-file name path
Pass the contents of file path as the argument name to Nix functions.
•
--arg-from-stdin name
Pass the contents of stdin as the argument name to Nix functions.
•
--argstr name string
Pass the string string as the argument name to Nix functions.
•
--debugger
Start an interactive environment if evaluation fails.
•
--eval-store store-url
The URL of the Nix store to use for evaluation, i.e. to store derivations (.drv files) and inputs referenced by them.
•
--impure
Allow access to mutable paths and repositories.
•
--include / -I path
Add path to search path entries used to resolve lookup paths
This option may be given multiple times.
Paths added through -I take precedence over the nix-path configuration setting and the NIX_PATH environment variable.
•
--override-flake original-ref resolved-ref
Override the flake registries, redirecting original-ref to resolved-ref.
•
--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.
DEPRECATED
Use --no-use-registries instead.
•
--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.
•
--output-lock-file flake-lock-path
Write the given lock file instead of flake.lock within the top-level flake.
•
--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.
DEPRECATED
Use nix flake update instead.
•
--reference-lock-file flake-lock-path
Read the given lock file instead of flake.lock within the top-level flake.
•
--update-input input-path
Update a specific flake input (ignoring its previous entry in the lock file).
DEPRECATED
Use nix flake update instead.
•
--debug
Set the logging verbosity level to ‘debug’.
•
--log-format format
Set the format of log output; one of raw, internal-json, bar or bar-with-logs.
•
--print-build-logs / -L
Print full build logs on standard error.
•
--quiet
Decrease the logging verbosity level.
•
--verbose / -v
Increase the logging verbosity level.

•
--help
Show usage information.
•
--offline
Disable substituters and consider all previously downloaded files up-to-date.
•
--option name value
Set the Nix configuration setting name to value (overriding nix.conf).
•
--refresh
Consider all previously downloaded files out-of-date.
•
--repair
During evaluation, rewrite missing or corrupted files in the Nix store. During building, rebuild missing or corrupted store paths.
•
--version
Show version information.

•
--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.

Note

See man nix.conf for overriding configuration settings with command line flags.