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nix develop

Run a bash shell that provides the build environment of a derivation.

Warning

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

Synopsis

nix develop [option...] installable

Note: this command's interface is based heavily around installables, which you may want to read about first (nix --help).

Examples

  • Start a shell with the build environment of the default package of the flake in the current directory:
## nix develop

Typical commands to run inside this shell are:

## configurePhase
## buildPhase
## installPhase

Alternatively, you can run whatever build tools your project uses directly, e.g. for a typical Unix project:

## ./configure --prefix=$out
## make
## make install
  • Run a particular build phase directly:
## nix develop --unpack
## nix develop --configure
## nix develop --build
## nix develop --check
## nix develop --install
## nix develop --installcheck
  • Start a shell with the build environment of GNU Hello:
## nix develop nixpkgs#hello
  • Record a build environment in a profile:
## nix develop --profile /tmp/my-build-env nixpkgs#hello
  • Use a build environment previously recorded in a profile:
## nix develop /tmp/my-build-env
  • Replace all occurrences of the store path corresponding to glibc.dev with a writable directory:
## nix develop --redirect nixpkgs#glibc.dev ~/my-glibc/outputs/dev

Note that this is useful if you're running a nix develop shell for nixpkgs#glibc in ~/my-glibc and want to compile another package against it.

  • Run a series of script commands:
## nix develop --command bash -c "mkdir build && cmake .. && make"

Description

nix develop starts a bash shell that provides an interactive build environment nearly identical to what Lix would use to build installable. Inside this shell, environment variables and shell functions are set up so that you can interactively and incrementally build your package.

Nix determines the build environment by building a modified version of the derivation installable that just records the environment initialised by stdenv and exits. This build environment can be recorded into a profile using --profile.

The prompt used by the bash shell can be customised by setting the bash-prompt, bash-prompt-prefix, and bash-prompt-suffix settings in nix.conf or in the flake's nixConfig attribute.

Flake output attributes

If no flake output attribute is given, nix develop tries the following flake output attributes:

  • devShells.<system>.default

  • packages.<system>.default

If a flake output name is given, nix develop tries the following flake output attributes:

  • devShells.<system>.<name>

  • packages.<system>.<name>

  • legacyPackages.<system>.<name>

Options

  • --build Run the build phase.

  • --check Run the check phase.

  • --command / -c command args Instead of starting an interactive shell, start the specified command and arguments.

  • --configure Run the configure phase.

  • --ignore-environment / -i Clear the entire environment (except those specified with --keep).

  • --install Run the install phase.

  • --installcheck Run the installcheck phase.

  • --keep / -k name Keep the environment variable name.

  • --phase phase-name The stdenv phase to run (e.g. build or configure).

  • --profile path The profile to operate on.

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

  • --unpack Run the unpack phase.

  • --unset / -u name Unset the environment variable name.

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.

  • --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 the Nix search path. The Nix search path is initialized from the colon-separated NIX_PATH environment variable, and is used to look up the location of Nix expressions using paths enclosed in angle brackets (i.e., <nixpkgs>).

For instance, passing

-I /home/eelco/Dev
-I /etc/nixos

will cause Lix to look for paths relative to /home/eelco/Dev and /etc/nixos, in that order. This is equivalent to setting the NIX_PATH environment variable to

/home/eelco/Dev:/etc/nixos

It is also possible to match paths against a prefix. For example, passing

-I nixpkgs=/home/eelco/Dev/nixpkgs-branch
-I /etc/nixos

will cause Lix to search for <nixpkgs/path> in /home/eelco/Dev/nixpkgs-branch/path and /etc/nixos/nixpkgs/path.

If a path in the Nix search path starts with http:// or https://, it is interpreted as the URL of a tarball that will be downloaded and unpacked to a temporary location. The tarball must consist of a single top-level directory. For example, passing

-I nixpkgs=https://github.com/NixOS/nixpkgs/archive/master.tar.gz

tells Lix to download and use the current contents of the master branch in the nixpkgs repository.

The URLs of the tarballs from the official nixos.org channels (see the manual page for nix-channel) can be abbreviated as channel:<channel-name>. For instance, the following two flags are equivalent:

-I nixpkgs=channel:nixos-21.05
-I nixpkgs=https://nixos.org/channels/nixos-21.05/nixexprs.tar.xz

You can also fetch source trees using flake URLs and add them to the search path. For instance,

-I nixpkgs=flake:nixpkgs

specifies that the prefix nixpkgs shall refer to the source tree downloaded from the nixpkgs entry in the flake registry. Similarly,

-I nixpkgs=flake:github:NixOS/nixpkgs/nixos-22.05

makes <nixpkgs> refer to a particular branch of the NixOS/nixpkgs repository on GitHub.

  • --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.

  • --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.

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

Logging-related options:

  • --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.

Miscellaneous global options:

  • --help Show usage information.

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

  • --option name value Set the Lix 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.

Options that change the interpretation of installables:

  • --expr / -E 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.