Derivation Attributes: `args` and `outputs`

> derivation { > # ... > builder = "${pkgs.python}/bin/python"; > # ... > }; > ``` ### Optional - [`args`]{#attr-args} ([List](@docroot@/language/types.md#type-list) of [String](@docroot@/language/types.md#type-string)) Default: `[ ]` See [args](@docroot@/store/derivation/index.md#args). > **Example** > > Pass arguments to Bash to interpret a shell command: > > ```nix > derivation { > # ... > builder = "/bin/bash"; > args = [ "-c" "echo hello world > $out" ]; > # ... > }; > ``` - [`outputs`]{#attr-outputs} ([List](@docroot@/language/types.md#type-list) of [String](@docroot@/language/types.md#type-string)) Default: `[ "out" ]` Symbolic outputs of the derivation. Each output name is passed to the [`builder`](#attr-builder) executable as an environment variable with its value set to the corresponding [store path]. By default, a derivation produces a single output called `out`. However, derivations can produce multiple outputs. This allows the associated [store objects](@docroot@/store/store-object.md) and their [closures](@docroot@/glossary.md#gloss-closure) to be copied or garbage-collected separately. > **Example** > > Imagine a library package that provides a dynamic library, header files, and documentation. > A program that links against such a library doesn’t need the header files and documentation at runtime, and it doesn’t need the documentation at build time. > Thus, the library package could specify: > > ```nix > derivation { > # ... > outputs = [ "lib" "dev" "doc" ]; > # ... > } > ``` > > This will cause Nix to pass environment variables `lib`, `dev`, and `doc` to the builder containing the intended store paths of each output. > The builder would typically do something like > > ```bash > ./configure \ > --libdir=$lib/lib \ > --includedir=$dev/include \ > --docdir=$doc/share/doc > ``` > > for an Autoconf-style package. The name of an output is combined with the name of the derivation to create the name part of the output's store path, unless it is `out`, in which case just the name of the derivation is used. > **Example** > > > ```nix

This section discusses the optional attributes `args` and `outputs` within the Nix `derivation` function. `args` is a list of strings passed to the builder executable, while `outputs` defines the symbolic outputs of the derivation, each becoming an environment variable for the builder. The default output is `out`, but multiple outputs can be specified for separating different parts of a package, such as libraries, headers, and documentation, allowing for more efficient dependency management.