# Stack's global flags and options Stack can also be configured by flags and options on the command line. Global flags and options apply to all of Stack's commands. In addition, all of Stack's commands accept the `--setup-info-yaml` and `--snapshot-location-base` options and the `--help` flag. ## `--allow-different-user` flag Restrictions: POSIX systems only Default: True, if inside Docker; false otherwise Enable/disable permitting users other than the owner of the [Stack root](../topics/stack_root.md) directory to use a Stack installation. For further information, see the documentation for the corresponding non-project specific configuration [option](yaml/non-project.md#allow-different-user). ## `--arch` option Pass the option `--arch ` to specify the relevant machine architecture. For further information, see the documentation for the corresponding non-project specific configuration [option](yaml/non-project.md#arch). ## `--bash-completion-index` option Visibility: Hidden See the [shell auto-completion](../topics/shell_autocompletion.md) documentation. ## `--bash-completion-script` option Visibility: Hidden See the [shell auto-completion](../topics/shell_autocompletion.md) documentation. ## `--bash-completion-index` option Visibility: Hidden See the [shell auto-completion](../topics/shell_autocompletion.md) documentation. ## `--color` or `-colour` options Pass the option `stack --color ` to specify when to use color in output. For further information, see the documentation for the corresponding non-project specific configuration [option](yaml/non-project.md#color). ## `--compiler` option Pass the option `--compiler ` to specify the compiler (and, implicitly, its boot packages). For further information, see the [`compiler`](yaml/non-project.md#compiler) non-project specific configuration option documentation. ## `--custom-preprocessor-extensions` option Pass the option `--custom-preprocessor-extensions ` to specify an extension used for a custom preprocessor. For further information, see the documentation for the corresponding project specific configuration [option](yaml/project.md#custom-preprocessor-extensions). ## `--docker*` flags and options Stack supports automatically performing builds inside a Docker container. For further information see `stack --docker-help` or the [Docker integration](../topics/docker_integration.md) documentation. ## `--[no-]dump-logs` flag Default: Dump warning logs Enables/disables the dumping of the build output logs for project packages to the console. For further information, see the documentation for the corresponding non-project specific configuration [option](yaml/non-project.md#dump-logs). ## `--extra-include-dirs` option Pass the option `--extra-include-dirs ` to specify an extra directory to check for C header files. The option can be specified multiple times. For further information, see the documentation for the corresponding non-project specific configuration [option](yaml/non-project.md#extra-include-dirs). ## `--extra-lib-dirs` option Pass the option `--extra-lib-dirs ` to specify an extra directory to check for libraries. The option can be specified multiple times. For further information, see the documentation for the corresponding non-project specific configuration [option](yaml/non-project.md#extra-lib-dirs). ## `--fish-completion-script` option Visibility: Hidden See the [shell auto-completion](../topics/shell_autocompletion.md) documentation. ## `--ghc-build` option Pass the option `--ghc-build ` to specify the relevant specialised GHC build. For further information, see the documentation for the corresponding non-project specific configuration [option](yaml/non-project.md#ghc-build). ## `--ghc-variant` option Pass the option `--ghc-variant ` to specify the relevant GHC variant. For further information, see the documentation for the corresponding non-project specific configuration [option](yaml/non-project.md#ghc-variant). ## `--help` or `-h` flags Pass the `--help` (or `-h`) flag to cause Stack to list its commands and flags and options common to those commands. Alternatively, command ~~~text stack ~~~ for the same information. ## `--[no-]hpack-force` flag [:octicons-tag-24: 3.1.1](https://github.com/commercialhaskell/stack/releases/tag/v3.1.1) Default: Disabled By default, Hpack 0.12.0 or later will decline to overwrite a Cabal file that was created by a more recent version of Hpack and Hpack 0.20.0 or later will decline to overwrite a Cabal file that has been modified manually. Pass the flag `--hpack-force` to allow Hpack to overwrite such a Cabal file. ## `--hpack-numeric-version` flag Pass the flag `--hpack-numeric-version` to cause Stack to report the numeric version of its built-in Hpack library to the standard output stream (e.g. `0.35.0`) and quit. ## `--[no-]install-ghc` flag Default: Enabled ([:octicons-tag-24: 1.6.1](https://github.com/commercialhaskell/stack/releases/tag/v1.6.1)) If the specified GHC version is not available, enables/disables Stack seeking to download and install that version if it is needed. On Windows, `--no-install-ghc` also disables the download and installation of the Stack-supplied MSYS2 when it is needed. For further information, see the documentation for the corresponding non-project specific configuration [option](yaml/non-project.md#install-ghc). !!! note The `--[no-]install-ghc` flag does not specify whether Stack checks the availability of either a 'system' GHC executable on the PATH or a Stack-supplied GHC executable. In that regard, see the [`system-ghc`](yaml/non-project.md#system-ghc) option. ## `--[no-]install-msys` flag [:octicons-tag-24: 3.5.1](https://github.com/commercialhaskell/stack/releases/tag/v3.5.1) Restrictions: Windows systems only Default: Same as the [`install-ghc`](yaml/non-project.md#install-ghc) setting (including if that is set on the command line) If Stack is checking for the Stack-supplied MSYS2 when Stack is setting up the environment, enables/disables the download and installation of MSYS2 when necessary. For further information, see the documentation for the corresponding non-project specific configuration [option](yaml/non-project.md#install-msys). To skip entirely checking for the Stack-supplied MSYS2, see the documentation for the [`skip-msys`](yaml/non-project.md#skip-msys) configuration option. ## `--jobs` or `-j` option Pass the option `--jobs ` to specify the number of concurrent jobs (Stack actions during building) to run. When [building GHC from source](../topics/GHC_from_source.md), specifies the `-j[]` flag of GHC's Hadrian build system. By default, Stack specifies a number of concurrent jobs equal to the number of CPUs (cores) that the machine has. In some circumstances, that default can cause some machines to run out of memory during building. If those circumstances arise, specify `--jobs 1`. This configuration option is distinct from GHC's own `-j[]` flag, which relates to parallel compilation of modules within a package. For further information, see the documentation for the corresponding non-project specific configuration option: [`jobs`](yaml/non-project.md#jobs). ## `--local-bin-path` option Pass the option `--local-bin-path ` to set the target directory for [`stack build --copy-bins`](../commands/build_command.md#-no-copy-bins-flag) and `stack install`. An absolute or relative path can be specified. A relative path at the command line is always assumed to be relative to the current directory. For further information, see the documentation for the corresponding non-project specific configuration [option](yaml/non-project.md#local-bin-path). ## `--lock-file` option Default: `read-write`, if snapshot specified in the project-level configuration file; `read-only`, if a different snapshot is specified on the command line. Pass the option `--lock-file ` to specify how Stack interacts with lock files. Valid modes are: * `error-on-write`: Stack reports an error, rather than write a lock file; * `ignore`: Stack ignores lock files; * `read-only`: Stack only reads lock files; and * `read-write`: Stack reads and writes lock files. ## `--[no-]modify-code-page` flag Restrictions: Windows systems only Default: Enabled Enables/disables setting the codepage to support UTF-8. For further information, see the documentation for the corresponding non-project specific configuration [option](yaml/non-project.md#modify-code-page). ## `--nix*` flags and options Stack can be configured to integrate with Nix. For further information, see `stack --nix-help` or the [Nix integration](../topics/nix_integration.md) documentation. ## `--numeric-version` flag Pass the flag `--numeric-version` to cause Stack to report its numeric version to the standard output stream (e.g. `2.9.1`) and quit. ## `--[no-]plan-in-log` flag [:octicons-tag-24: 2.13.1](https://github.com/commercialhaskell/stack/releases/tag/v2.13.1) Default: Disabled Enables/disables the logging of build plan construction in debug output. Information about the build plan construction can be lengthy. If you do not need it, it is best omitted from the debug output. ## `--resolver` option [:octicons-thumbsdown-24: 3.9.3](https://github.com/commercialhaskell/stack/releases/tag/v3.9.3) The `--resolver` option (deprecated) and the [`--snapshot`](#-snapshot-option) option are synonyms. More than one of these options is prohibited. ## `--[no-]rsl-in-log` flag [:octicons-tag-24: 2.9.1](https://github.com/commercialhaskell/stack/releases/tag/v2.9.1) Default: Disabled Enables/disables the logging of the raw snapshot layer (rsl) in debug output. Information about the raw snapshot layer can be lengthy. If you do not need it, it is best omitted from the debug output. ## `--[no-]script-no-run-compile` flag Default: Disabled Enables/disables the use of options `--no-run --compile` with the [`stack script` command](../commands/script_command.md). ## `--silent` flag Equivalent to the `--verbosity silent` option. ## `--[no-]skip-ghc-check` option Default: Disabled Enables/disables the skipping of checking the GHC version and architecture. For further information, see the documentation for the corresponding non-project specific configuration [option](yaml/non-project.md#skip-ghc-check). ## `--[no-]skip-msys` option Restrictions: Windows systems only Default: Disabled Enables/disables the skipping of checking for the Stack-supplied MSYS2 (and installing that MSYS2, if it is not installed) when Stack is setting up the environment. For further information, see the documentation for the corresponding non-project specific configuration [option](yaml/non-project.md#skip-msys). To prevent installation of MSYS2, if it is not installed, see the documentation for the [`install-msys`](yaml/non-project.md#install-msys) configuration option. ## `--snapshot` option [:octicons-tag-24: 2.15.1](https://github.com/commercialhaskell/stack/releases/tag/v2.15.1) Pass the option `--snapshot ` to specify the snapshot. For further information, see the [`snapshot`](yaml/project.md#snapshot) project-specific configuration option documentation. ## `--stack-colors` or `--stack-colours` options Pass the option `--stack-colors ` to specify Stack's output styles. For further information, see the documentation for the corresponding non-project specific configuration [option](yaml/non-project.md#stack-colors). ## `--stack-root` option Overrides: `STACK_ROOT` environment variable Pass the option `--stack-root ` to specify the path to the [Stack root](../topics/stack_root.md) directory. The path must be an absolute one. ## `--stack-yaml` or `-w` option Default: `stack.yaml` Overrides: `STACK_YAML` enviroment variable Pass the option `--stack-yaml ` to specify Stack's project-level YAML configuration file. ## `--[no-]system-ghc` flag Default: Disabled ([:octicons-tag-24: 1.3.0](https://github.com/commercialhaskell/stack/releases/tag/v1.3.0)) Enables/disables Stack seeking to use a 'system' GHC executable (that is, one on the PATH) rather than a Stack-supplied GHC executable (or vice versa, if disabled). For further information, see the documentation for the corresponding non-project specific configuration [option](yaml/non-project.md#system-ghc). !!! note The `--[no-]system-ghc` flag does not specify Stack's behaviour if the specified GHC version is not already available. In that regard, see the [`install-ghc`](yaml/non-project.md#install-ghc) option. ## `--[no-]terminal` flag Default: Stack is running in a terminal (as detected) Enables/disables whether Stack is running in a terminal. ## `--terminal-width` option Default: the terminal width (if detected); otherwise `100` Pass the option `--terminal-width ` to specify the width of the terminal, used by Stack's pretty printed messages. ## `--[no-]time-in-logs` flag Default: Enabled Enables/disables the inclusion of time stamps against logging entries when the verbosity level is 'debug'. ## `--verbose` or `-v` flags Equivalent to the `--verbosity debug` option. ## `--verbosity` option Default: `info` Pass the option `--verbosity ` to specify the level for logging. Possible levels are `silent`, `error`, `warn`, `info` and `debug`, in order of increasing amounts of information provided by logging. ## `--version` flag Pass the flag `--version` to cause Stack to report its version to standard output and quit. For versions that are release candidates, the report will list the dependencies that Stack has been compiled with. ## `--with-gcc` option Pass the option `--with-gcc ` to specify use of a GCC executable. For further information, see the documentation for the corresponding non-project specific configuration [option](yaml/non-project.md#with-gcc). ## `--with-hpack` option Pass the option `--with-hpack ` to specify use of an Hpack executable. For further information, see the documentation for the corresponding non-project specific configuration [option](yaml/non-project.md#with-hpack). ## `--work-dir` option Default: `.stack-work` Overrides: [`STACK_WORK`](environment_variables.md#stack_work) environment variable, and [`work-dir`](yaml/non-project.md#work-dir) non-project specific configuration option. Pass the option `--work-dir ` to specify the path to Stack's work directory, within a local project or package directory. The path must be a relative one, relative to the the root directory of the project or package. The relative path cannot include a `..` (parent directory) component. ## `--zsh-completion-script` option Visibility: Hidden See the [shell auto-completion](../topics/shell_autocompletion.md) documentation. ## `--setup-info-yaml` command option Default: `https://raw.githubusercontent.com/commercialhaskell/stackage-content/master/stack/stack-setup-2.yaml` The `--setup-info-yaml ` command option specifies the location of a `setup-info` dictionary. The option can be specified multiple times. ## `--snapshot-location-base` command option Default: `https://raw.githubusercontent.com/commercialhaskell/stackage-snapshots/master` The `--snapshot-location-base ` command option specifies the base location of snapshots. For further information, see the documentation for the corresponding non-project specific configuration [option](yaml/non-project.md#snapshot-location-base). ## `--help` or `-h` command flags If Stack is passed the `--help` (or `-h`) command flag, it will output help for the command.