Options

Available only in Nix

See how commands.<name> (link) maps to commands.* (link).

commands.<name>.*

A config for command(s) when the commands option is an attrset.

Type:

(package or string convertible to it) or (list with two elements of types: [ string (package or string convertible to it) ]) or (nestedOptions) or (flatOptions)

Example value:

{
  category = [
    {
      packages.grep = pkgs.gnugrep;
    }
    pkgs.python3
    [ "[package] vercel description" "nodePackages.vercel" ]
    "nodePackages.yarn"
  ];
}

Declared in:

commands.<name>.*.packages (nestedOptions)

A leaf value:

  1. When a string with a value <string>, devshell tries to resolve a derivation pkgs.<string> and use it as package (flatOptions).

  2. When a derivation, it's used as package (flatOptions).

  3. When a list with two elements:

    1. The first element is a string that is used to select help (flatOptions).

      Priority of this string (if present) when selecting help (flatOptions): 4.

      Lowest priority: 1.

    2. The second element is interpreted as if the leaf value were initially a string or a derivation.

A path to a leaf value is concatenated via . and used as name (flatOptions).

Priority of package.meta.description (if present in the resolved package (flatOptions)) when selecting help (flatOptions): 2

Lowest priority: 1.

A user may prefer to not bring to the environment some of the packages.

Priority of expose = false when selecting expose (flatOptions): 1.

Lowest priority: 1.

Type:

(nested (max depth is 100) attribute set of ((package or string convertible to it) or (list with two elements of types: [ string (package or string convertible to it) ])))

Default value:

{ }

Example value:

{
  packages.a.b = pkgs.jq;
}

Declared in:

commands.<name>.*.commands (nestedOptions)

A leaf value:

  1. When a string, it's used as command (flatOptions).

  2. When a list with two elements:

    1. The first element of type string with a value <string> is used to select help (flatOptions).

      Priority of the <string> (if present) when selecting help (flatOptions): 4

      Lowest priority: 1.

    2. The second element of type string is used as command (flatOptions).

A path to the leaf value is concatenated via . and used as name (flatOptions).

Type:

(nested (max depth is 100) attribute set of (string or (list with two elements of types: [ string string ])))

Default value:

{ }

Declared in:

commands.<name>.*.expose (nestedOptions)

Can be used as expose (flatOptions) for all packages (nestedOptions) and commands (nestedOptions).

Priority of this option when selecting expose (flatOptions): 2.

When selecting expose (flatOptions) for

  • package (flatOptions), priority of false: 1.
  • command (flatOptions), priority of true: 1.

Lowest priority: 1.

Type:

null or boolean

Default value:

null

Example value:

{
  expose = true;
}

Declared in:

commands.<name>.*.exposes (nestedOptions)

A leaf value can be used as expose (flatOptions) for package (flatOptions) or command (flatOptions) with a matching path in packages (nestedOptions) or commands (nestedOptions).

Priority of this option when selecting expose (flatOptions): 3.

When selecting expose (flatOptions) for

  • package (flatOptions), priority of false: 1.
  • command (flatOptions), priority of true: 1.

Lowest priority: 1.

Type:

(nested (max depth is 100) attribute set of boolean)

Default value:

{ }

Example value:

{
  packages.a.b = pkgs.jq;
  exposes.a.b = true;
}

Declared in:

commands.<name>.*.help (nestedOptions)

Can be used as hel (flatOptions) for all packages (nestedOptions) and commands (nestedOptions).

Priority of this option when selecting a help (flatOptions): 1.

Lowest priority: 1.

Type:

string

Default value:

""

Example value:

{
  help = "default help";
}

Declared in:

commands.<name>.*.helps (nestedOptions)

A leaf value can be used as help (flatOptions) for package (flatOptions) or command (flatOptions) with a matching path in packages (nestedOptions) or commands (nestedOptions).

Priority of this option when selecting help (flatOptions): 3.

Lowest priority: 1.

Type:

(nested (max depth is 100) attribute set of string)

Default value:

{ }

Example value:

{
  packages.a.b = pkgs.jq;
  helps.a.b = "run jq";
}

Declared in:

commands.<name>.*.interpolate (nestedOptions)

When true, shell variables in help (flatOptions) can be interpolated.

Priority of this option when selecting interpolate (flatOptions): 1.

Lowest priority: 1.

Type:

null or boolean

Default value:

null

Example value:

true

Declared in:

commands.<name>.*.interpolates (nestedOptions)

A leaf value is used as interpolate (flatOptions) for package (flatOptions) or command (flatOptions) with a matching path in packages (nestedOptions) or commands (nestedOptions).

Priority of this option when selecting interpolate (flatOptions): 2.

Lowest priority: 1.

Type:

(nested (max depth is 100) attribute set of boolean)

Default value:

{ }

Example value:

true

Declared in:

commands.<name>.*.prefix (nestedOptions)

Can be used as prefix (flatOptions) for all packages (nestedOptions) and commands (nestedOptions).

Priority of this option when selecting a prefix (flatOptions): 1.

Lowest priority: 1.

Type:

string

Default value:

""

Example value:

{
  prefix = "nix run .#";
}

Declared in:

commands.<name>.*.prefixes (nestedOptions)

A leaf value becomes prefix (flatOptions) of package (flatOptions) or command (flatOptions) with a matching path in packages (nestedOptions) or commands (nestedOptions).

Priority of this option when selecting a prefix (flatOptions): 2.

Lowest priority: 1.

Type:

(nested (max depth is 100) attribute set of string)

Default value:

{ }

Example value:

{
  packages.a.b = pkgs.jq;
  prefixes.a.b = "nix run ../#";
}

Declared in:

commands.<name>.*.package (flatOptions)

Used to bring in a specific package. This package will be added to the environment.

Type:

null or (package or string convertible to it) or package

Default value:

null

Declared in:

commands.<name>.*.category (flatOptions)

Sets a free text category under which this command is grouped and shown in the devshell menu.

Type:

string

Default value:

"[general commands]"

Declared in:

commands.<name>.*.command (flatOptions)

If defined, it will add a script with the name of the command, and the content of this value.

By default it generates a bash script, unless a different shebang is provided.

Type:

null or string

Default value:

null

Example value:

''
  #!/usr/bin/env python
  print("Hello")
''

Declared in:

commands.<name>.*.expose (flatOptions)

When true, command (flatOptions) or package (flatOptions) will be added to the environment.

Otherwise, they will not be added to the environment, but will be printed in the devshell menu.

Type:

boolean

Default value:

true

Example value:

true

Declared in:

commands.<name>.*.help (flatOptions)

Describes what the command does in one line of text.

Type:

null or string

Default value:

null

Declared in:

commands.<name>.*.interpolate (flatOptions)

When true or when null and devshell.menu.interpolate is true, shell variables in help (flatOptions) will be interpolated.

Otherwise, they will not.

Type:

null or boolean

Default value:

null

Example value:

true

Declared in:

commands.<name>.*.name (flatOptions)

Name of the command.

Defaults to a package (flatOptions) name or pname if present.

The value of this option is required for command (flatOptions).

Type:

null or string matching [^$
]+

Default value:

null

Declared in:

commands.<name>.*.prefix (flatOptions)

Prefix of the command name in the devshell menu.

Type:

string

Default value:

""

Declared in:

Available in Nix and TOML

commands

Add commands to the environment.

Type:

(list of ((package or string convertible to it) or (list with two elements of types: [ string (package or string convertible to it) ]) or (flatOptions))) or (attribute set of list of ((package or string convertible to it) or (list with two elements of types: [ string (package or string convertible to it) ]) or (nestedOptions) or (flatOptions)))

Default value:

[ ]

Example value:

{
  packages = [
    "diffutils"
    "goreleaser"
  ];
  scripts = [
    {
      prefix = "nix run .#";
      inherit packages;
    }
    {
      name = "nix fmt";
      help = "format Nix files";
    }
  ];
  utilites = [
    [ "GitHub utility" "gitAndTools.hub" ]
    [ "golang linter" "golangci-lint" ]
  ];
}

Declared in:

commands.*

A config for a command when the commands option is a list.

Type:

(package or string convertible to it) or (list with two elements of types: [ string (package or string convertible to it) ]) or (flatOptions)

Example value:

[
  {
    category = "scripts";
    package = "black";
  }
  [ "[package] print hello" "hello" ]
  "nodePackages.yarn"
]

Declared in:

commands.*.package (flatOptions)

Used to bring in a specific package. This package will be added to the environment.

Type:

null or (package or string convertible to it) or package

Default value:

null

Declared in:

commands.*.category (flatOptions)

Sets a free text category under which this command is grouped and shown in the devshell menu.

Type:

string

Default value:

"[general commands]"

Declared in:

commands.*.command (flatOptions)

If defined, it will add a script with the name of the command, and the content of this value.

By default it generates a bash script, unless a different shebang is provided.

Type:

null or string

Default value:

null

Example value:

''
  #!/usr/bin/env python
  print("Hello")
''

Declared in:

commands.*.expose (flatOptions)

When true, command (flatOptions) or package (flatOptions) will be added to the environment.

Otherwise, they will not be added to the environment, but will be printed in the devshell menu.

Type:

boolean

Default value:

true

Example value:

true

Declared in:

commands.*.help (flatOptions)

Describes what the command does in one line of text.

Type:

null or string

Default value:

null

Declared in:

commands.*.interpolate (flatOptions)

When true or when null and devshell.menu.interpolate is true, shell variables in help (flatOptions) will be interpolated.

Otherwise, they will not.

Type:

null or boolean

Default value:

null

Example value:

true

Declared in:

commands.*.name (flatOptions)

Name of the command.

Defaults to a package (flatOptions) name or pname if present.

The value of this option is required for command (flatOptions).

Type:

null or string matching [^$
]+

Default value:

null

Declared in:

commands.*.prefix (flatOptions)

Prefix of the command name in the devshell menu.

Type:

string

Default value:

""

Declared in:

devshell.packages

The set of packages to appear in the project environment.

Those packages come from https://nixos.org/NixOS/nixpkgs and can be searched by going to https://search.nixos.org/packages

Type:

list of (package or string convertible to it)

Default value:

[ ]

Declared in:

devshell.packagesFrom

Add all the build dependencies from the listed packages to the environment.

Type:

list of (package or string convertible to it)

Default value:

[ ]

Declared in:

devshell.interactive.<name>.deps

A list of other steps that this one depends on.

Type:

list of string

Default value:

[ ]

Declared in:

devshell.interactive.<name>.text

Script to run.

Type:

string

Declared in:

devshell.load_profiles

Whether to enable load etc/profiles.d/*.sh in the shell. Type:

boolean

Default value:

false

Example value:

true

Declared in:

devshell.menu

Controls devshell menu

Type:

submodule

Default value:

{ }

Example value:

{
  interpolate = true;
  width = 75;
}

Declared in:

devshell.menu.interpolate

Whether to enable interpolation in the devshell menu. Type:

boolean

Default value:

false

Example value:

true

Declared in:

devshell.menu.width

Width of the devshell message.

Type:

positive integer or floating point number, meaning >0

Default value:

75

Example value:

75

Declared in:

devshell.meta

Metadata, such as 'meta.description'. Can be useful as metadata for downstream tooling.

Type:

attribute set of anything

Default value:

{ }

Declared in:

devshell.motd

Message Of The Day.

This is the welcome message that is being printed when the user opens the shell.

You may use any valid ansi color from the 8-bit ansi color table. For example, to use a green color you would use something like {106}. You may also use {bold}, {italic}, {underline}. Use {reset} to turn off all attributes.

Type:

string

Default value:

''
  {202}🔨 Welcome to devshell{reset}
  $(type -p menu &>/dev/null && menu)
''

Declared in:

devshell.name

Name of the shell environment. It usually maps to the project name.

Type:

string

Default value:

"devshell"

Declared in:

devshell.prj_root_fallback

If IN_NIX_SHELL is nonempty, or DIRENV_IN_ENVRC is set to '1', then PRJ_ROOT is set to the value of PWD.

This option specifies the path to use as the value of PRJ_ROOT in case IN_NIX_SHELL is empty or unset and DIRENV_IN_ENVRC is any value other than '1'.

Set this to null to force PRJ_ROOT to be defined at runtime (except if IN_NIX_SHELL or DIRENV_IN_ENVRC are defined as described above).

Otherwise, you can set this to a string representing the desired default path, or to a submodule of the same type valid in the 'env' options list (except that the 'name' field is ignored).

Type:

null or ((submodule) or non-empty string convertible to it)

Default value:

{
  eval = "$PWD";
}

Example value:

{
  # Use the top-level directory of the working tree
  eval = "$(git rev-parse --show-toplevel)";
};

Declared in:

devshell.prj_root_fallback.eval

Like value but not evaluated by Bash. This allows to inject other variable names or even commands using the $() notation.

Type:

null or string

Default value:

null

Example value:

"$OTHER_VAR"

Declared in:

devshell.prj_root_fallback.name

Name of the environment variable Type:

string

Declared in:

devshell.prj_root_fallback.prefix

Prepend to PATH-like environment variables.

For example name = "PATH"; prefix = "bin"; will expand the path of ./bin and prepend it to the PATH, separated by ':'.

Type:

null or string

Default value:

null

Example value:

"bin"

Declared in:

devshell.prj_root_fallback.unset

Whether to enable unsets the variable. Type:

boolean

Default value:

false

Example value:

true

Declared in:

devshell.prj_root_fallback.value

Shell-escaped value to set Type:

null or string or signed integer or boolean or package

Default value:

null

Declared in:

devshell.startup.<name>.deps

A list of other steps that this one depends on.

Type:

list of string

Default value:

[ ]

Declared in:

devshell.startup.<name>.text

Script to run.

Type:

string

Declared in:

env

Add environment variables to the shell.

Type:

list of (submodule)

Default value:

[ ]

Example value:

[
  {
    name = "HTTP_PORT";
    value = 8080;
  }
  {
    name = "PATH";
    prefix = "bin";
  }
  {
    name = "XDG_CACHE_DIR";
    eval = "$PRJ_ROOT/.cache";
  }
  {
    name = "CARGO_HOME";
    unset = true;
  }
]

Declared in:

env.*.eval

Like value but not evaluated by Bash. This allows to inject other variable names or even commands using the $() notation.

Type:

null or string

Default value:

null

Example value:

"$OTHER_VAR"

Declared in:

env.*.name

Name of the environment variable Type:

string

Declared in:

env.*.prefix

Prepend to PATH-like environment variables.

For example name = "PATH"; prefix = "bin"; will expand the path of ./bin and prepend it to the PATH, separated by ':'.

Type:

null or string

Default value:

null

Example value:

"bin"

Declared in:

env.*.unset

Whether to enable unsets the variable. Type:

boolean

Default value:

false

Example value:

true

Declared in:

env.*.value

Shell-escaped value to set Type:

null or string or signed integer or boolean or package

Default value:

null

Declared in:

extra.locale.package

Set the glibc locale package that will be used on Linux Type:

package

Default value:

"pkgs.glibcLocales"

Declared in:

extra.locale.lang

Set the language of the project Type:

null or string

Default value:

null

Example value:

"en_GB.UTF-8"

Declared in:

git.hooks.enable

Whether to enable install .git/hooks on shell entry. Type:

boolean

Default value:

false

Example value:

true

Declared in:

git.hooks.applypatch-msg.text

Text of the script to install Type:

string

Default value:

""

Declared in:

git.hooks.commit-msg.text

Text of the script to install Type:

string

Default value:

""

Declared in:

git.hooks.fsmonitor-watchman.text

Text of the script to install Type:

string

Default value:

""

Declared in:

git.hooks.post-update.text

Text of the script to install Type:

string

Default value:

""

Declared in:

git.hooks.pre-applypatch.text

Text of the script to install Type:

string

Default value:

""

Declared in:

git.hooks.pre-commit.text

Text of the script to install Type:

string

Default value:

""

Declared in:

git.hooks.pre-merge-commit.text

Text of the script to install Type:

string

Default value:

""

Declared in:

git.hooks.pre-push.text

Text of the script to install Type:

string

Default value:

""

Declared in:

git.hooks.pre-rebase.text

Text of the script to install Type:

string

Default value:

""

Declared in:

git.hooks.prepare-commit-msg.text

Text of the script to install Type:

string

Default value:

""

Declared in:

language.c.compiler

Which C compiler to use Type:

package or string convertible to it

Default value:

"pkgs.clang"

Declared in:

language.c.includes

C dependencies from nixpkgs Type:

list of (package or string convertible to it)

Default value:

[ ]

Declared in:

language.c.libraries

Use this when another language dependens on a dynamic library Type:

list of (package or string convertible to it)

Default value:

[ ]

Declared in:

language.go.package

Which go package to use Type:

package or string convertible to it

Default value:

<derivation go-1.21.5>

Example value:

pkgs.go

Declared in:

language.go.GO111MODULE

Enable Go modules Type:

one of "on", "off", "auto"

Default value:

"on"

Declared in:

language.perl.package

Which Perl package to use Type:

package or string convertible to it

Default value:

<derivation perl-5.38.2>

Example value:

pkgs.perl538

Declared in:

language.perl.extraPackages

List of extra packages (coming from perl5XXPackages) to add Type:

list of (package or string convertible to it)

Default value:

[ ]

Example value:

[ perl538Packages.FileNext ]

Declared in:

language.perl.libraryPaths

List of paths to add to PERL5LIB Type:

list of string

Default value:

[ ]

Example value:

[ ./lib ]

Declared in:

language.ruby.package

Ruby version used by your project Type:

package or string convertible to it

Default value:

"pkgs.ruby_3_2"

Declared in:

language.ruby.nativeDeps

Use this when your gems depend on a dynamic library Type:

list of (package or string convertible to it)

Default value:

[ ]

Declared in:

language.rust.enableDefaultToolchain

Enable the default rust toolchain coming from nixpkgs Type:

boolean

Default value:

"true"

Declared in:

language.rust.packageSet

Which rust package set to use Type:

attribute set

Default value:

"pkgs.rustPlatform"

Declared in:

language.rust.tools

Which rust tools to pull from the platform package set Type:

list of string

Default value:

[
  "rustc"
  "cargo"
  "clippy"
  "rustfmt"
]

Declared in:

serviceGroups

Add services to the environment. Services can be used to group long-running processes.

Type:

attribute set of (submodule)

Default value:

{ }

Declared in:

serviceGroups.<name>.description

Short description of the service group, shown in generated commands

Type:

null or string

Default value:

null

Declared in:

serviceGroups.<name>.name

Name of the service group. Defaults to attribute name in groups.

Type:

null or string

Default value:

null

Declared in:

serviceGroups.<name>.services

Attrset of services that should be run in this group.

Type:

attribute set of (submodule)

Default value:

{ }

Declared in:

serviceGroups.<name>.services.<name>.command

Command to execute.

Type:

string

Declared in:

serviceGroups.<name>.services.<name>.name

Name of this service. Defaults to attribute name in group services.

Type:

null or string

Default value:

null

Declared in:

services.postgres.package

Which version of postgres to use Type:

package or string convertible to it

Default value:

"pkgs.postgresql"

Declared in:

services.postgres.createUserDB

Create a database named like current user on startup. This option only makes sense when setupPostgresOnStartup is true.

Type:

boolean

Default value:

true

Declared in:

services.postgres.initdbArgs

Additional arguments passed to initdb during data dir initialisation.

Type:

list of string

Default value:

[
  "--no-locale"
]

Example value:

[
  "--data-checksums"
  "--allow-group-access"
]

Declared in:

services.postgres.setupPostgresOnStartup

Whether to enable call setup-postgres on startup. Type:

boolean

Default value:

false

Example value:

true

Declared in:

Extra options available only in Nix

_module.args

Additional arguments passed to each module in addition to ones like lib, config, and pkgs, modulesPath.

This option is also available to all submodules. Submodules do not inherit args from their parent module, nor do they provide args to their parent module or sibling submodules. The sole exception to this is the argument name which is provided by parent modules to a submodule and contains the attribute name the submodule is bound to, or a unique generated name if it is not bound to an attribute.

Some arguments are already passed by default, of which the following cannot be changed with this option:

  • {var}lib: The nixpkgs library.

  • {var}config: The results of all options after merging the values from all modules together.

  • {var}options: The options declared in all modules.

  • {var}specialArgs: The specialArgs argument passed to evalModules.

  • All attributes of {var}specialArgs

    Whereas option values can generally depend on other option values thanks to laziness, this does not apply to imports, which must be computed statically before anything else.

    For this reason, callers of the module system can provide specialArgs which are available during import resolution.

    For NixOS, specialArgs includes {var}modulesPath, which allows you to import extra modules from the nixpkgs package tree without having to somehow make the module aware of the location of the nixpkgs or NixOS directories.

    { modulesPath, ... }: {
  imports = [
    (modulesPath + "/profiles/minimal.nix")
  ];
}

For NixOS, the default value for this option includes at least this argument:

  • {var}pkgs: The nixpkgs package set according to the {option}nixpkgs.pkgs option.

Type:

lazy attribute set of raw value

Declared in: