NAME

       dune-fmt - Format source code.

SYNOPSIS

       dune fmt [OPTION]…

DESCRIPTION

       dune fmt runs the formatter on the source code. The formatter is automatically selected.
       ocamlformat is used to format OCaml source code (*.ml and *.mli files) and refmt is used
       to format Reason source code (*.re and *.rei files).

OPTIONS

       --action-stderr-on-success=VAL
           Same as --action-stdout-on-success but for standard error instead of standard output.
           A good default for large mono-repositories is --action-stdout-on-success=swallow
           --action-stderr-on-success=must-be-empty. This ensures that a successful build has a
           "clean" empty output.

       --action-stdout-on-success=VAL
           Specify how to deal with the standard output of actions when they succeed. Possible
           values are: print to just print it to Dune's output, swallow to completely ignore it
           and must-be-empty to enforce that the action printed nothing. With must-be-empty, Dune
           will consider that the action failed if it printed something to its standard output.
           The default is print.

       --build-info
           Show build information.

       --display-separate-messages
           Separate error messages with a blank line.

       --error-reporting=VAL (absent=deterministic)
           Controls when the build errors are reported. early reports errors as soon as they are
           discovered. deterministic reports errors at the end of the build in a deterministic
           order. twice reports each error twice: once as soon as the error is discovered and
           then again at the end of the build, in a deterministic order.

       -f, --force
           Force actions associated to aliases to be re-executed even if their dependencies
           haven't changed.

       --file-watcher=VAL (absent=automatic)
           Mechanism to detect changes in the source. Automatic to make dune run an external
           program to detect changes. Manual to notify dune that files have changed manually.

       --passive-watch-mode
           Similar to [--watch], but only start a build when instructed externally by an RPC.

       --preview
           Just print the changes that would be made without actually applying them. This takes
           precedence over auto-promote as that flag is assumed for this command.

       --sandbox=VAL (absent DUNE_SANDBOX env)
           Set sandboxing mode. Some actions require a certain sandboxing mode, so they will
           ignore this setting. The allowed values are: none, symlink, copy, hardlink.

       --stop-on-first-error
           Stop the build as soon as an error is encountered.

       -w, --watch
           Instead of terminating build after completion, wait continuously for file changes.

       --wait-for-filesystem-clock
           Dune digest file contents for better incrementally. These digests are themselves
           cached. In some cases, Dune needs to drop some digest cache entries in order for
           things to be reliable. This option makes Dune wait for the file system clock to
           advance so that it doesn't need to drop anything. You should probably not care about
           this option; it is mostly useful for Dune developers to make Dune tests of the digest
           cache more reproducible.

COMMON OPTIONS

       These options are common to all commands.

       --always-show-command-line
           Always show the full command lines of programs executed by dune.

       --auto-promote
           Automatically promote files. This is similar to running dune promote after the build.

       --build-dir=FILE (absent DUNE_BUILD_DIR env)
           Specified build directory. _build if unspecified

       --cache=VAL (absent DUNE_CACHE env)
           Enable or disable Dune cache (either enabled or disabled). Default is `disabled'.

       --cache-check-probability=VAL (absent DUNE_CACHE_CHECK_PROBABILITY env)
           Check build reproducibility by re-executing randomly chosen rules and comparing their
           results with those stored in Dune cache. Note: by increasing the probability of such
           checks you slow down the build. The default probability is zero, i.e. no rules are
           checked.

       --cache-storage-mode=VAL (absent DUNE_CACHE_STORAGE_MODE env)
           Dune cache storage mode (one of auto, hardlink or copy). Default is `auto'.

       --config-file=FILE
           Load this configuration file instead of the default one.

       --debug-artifact-substitution
           Print debugging info about artifact substitution

       --debug-backtraces
           Always print exception backtraces.

       --debug-cache=VAL
           Show debug messages on cache misses for the given cache layers. Value is a
           comma-separated list of cache layer names. All available cache layers:
           shared,workspace-local,fs.

       --debug-dependency-path
           In case of error, print the dependency path from the targets on the command line to
           the rule that failed.

       --debug-digests
           Explain why Dune decides to re-digest some files

       --debug-load-dir
           Print debugging info about directory loading

       --default-target=TARGET (absent=@@default)
           Set the default target that is used when none is specified to dune build.

       --diff-command=VAL (absent DUNE_DIFF_COMMAND env)
           Shell command to use to diff files. Use - to disable printing the diff.

       --disable-promotion (absent DUNE_DISABLE_PROMOTION env)
           Disable all promotion rules

       --display=MODE
           Control the display mode of Dune. See dune-config(5) for more details. Valid values
           for this option are progress, verbose, short, quiet or tui.

       --dump-gc-stats=FILE
           Dump the garbage collector stats to a file after the build is complete.

       --dump-memo-graph=FILE
           Dump the dependency graph to a file after the build is complete.

       --dump-memo-graph-format=FORMAT (absent=gexf)
           Set the file format used by --dump-memo-graph

       --dump-memo-graph-with-timing
           Re-run each cached node in the Memo graph after building and include the run duration
           in the output of --dump-memo-graph. Since all nodes contain a cached value, each
           measurement will only account for a single node.

       --help[=FMT] (default=auto)
           Show this help in format FMT. The value FMT must be one of auto, pager, groff or
           plain. With auto, the format is pager or plain whenever the TERM env var is dumb or
           undefined.

       --ignore-lock-dir
           Ignore dune.lock/ directory.

       --ignore-promoted-rules
           Ignore rules with (mode promote), except ones with (only ...). The variable
           %{ignoring_promoted_rules} in dune files reflects whether this option was passed or
           not.

       --instrument-with=BACKENDS (absent DUNE_INSTRUMENT_WITH env)
           Enable instrumentation by BACKENDS. BACKENDS is a comma-separated list of library
           names, each one of which must declare an instrumentation backend.

       -j JOBS
           Run no more than JOBS commands simultaneously.

       --no-buffer
           Do not buffer the output of commands executed by dune. By default dune buffers the
           output of subcommands, in order to prevent interleaving when multiple commands are
           executed in parallel. However, this can be an issue when debugging long running tests.
           With --no-buffer, commands have direct access to the terminal. Note that as a result
           their output won't be captured in the log file. You should use this option in
           conjunction with -j 1, to avoid interleaving. Additionally you should use --verbose as
           well, to make sure that commands are printed before they are being executed.

       --no-config
           Do not load the configuration file

       --no-print-directory
           Suppress "Entering directory" messages.

       --only-packages=PACKAGES
           Ignore stanzas referring to a package that is not in PACKAGES. PACKAGES is a
           comma-separated list of package names. Note that this has the same effect as deleting
           the relevant stanzas from dune files. It is mostly meant for releases. During
           development, it is likely that what you want instead is to build a particular
           <package>.install target.

       -p PACKAGES, --for-release-of-packages=PACKAGES (required)
           Shorthand for --release --only-packages PACKAGE. You must use this option in your
           <package>.opam files, in order to build only what's necessary when your project
           contains multiple packages as well as getting reproducible builds.

       --print-metrics
           Print out various performance metrics after every build.

       --profile=VAL (absent DUNE_PROFILE env)
           Select the build profile, for instance dev or release. The default is dev.

       --promote-install-files[=VAL] (default=true)
           Promote any generated <package>.install files to the source tree.

       --release
           Put dune into a reproducible release mode. Shorthand for --root .
           --ignore-promoted-rules --no-config --profile release --always-show-command-line
           --promote-install-files --require-dune-project-file --ignore-lock-dir --default-target
           @install. You should use this option for release builds. For instance, you must use
           this option in your <package>.opam files. Except if you already use -p, as -p implies
           this option.

       --require-dune-project-file[=VAL] (default=true)
           Fail if a dune-project file is missing.

       --root=DIR
           Use this directory as workspace root instead of guessing it. Note that this option
           doesn't change the interpretation of targets given on the command line. It is only
           intended for scripts.

       --store-orig-source-dir (absent DUNE_STORE_ORIG_SOURCE_DIR env)
           Store original source location in dune-package metadata.

       --terminal-persistence=MODE
           Change how the log of build results are displayed to the console between rebuilds
           while in --watch mode. Supported modes: preserve, clear-on-rebuild,
           clear-on-rebuild-and-flush-history.

       --trace-extended
           Output extended trace data (requires trace-file).

       --trace-file=FILE
           Output trace data in catapult format (compatible with chrome://tracing).

       --verbose
           Same as --display verbose

       --version
           Show version information.

       --watch-exclusions=REGEX
           Adds a POSIX regular expression that will exclude matching directories from `dune
           build --watch`. The option --watch-exclusions can be repeated to add multiple
           exclusions. Semicolons can be also used as a separator. If no exclusions are provided,
           then a standard set of exclusions is used; however, if one or more --watch-exclusions
           are used, none of the standard exclusions are used. The standard exclusions are:
           ^_opam /_opam ^_esy /_esy ^\.#.* /\.#.* ~$ ^#[^#]*#$ /#[^#]*#$ ^4913$ /4913$ /.git
           /.hg :/windows

       --workspace=FILE (absent DUNE_WORKSPACE env)
           Use this specific workspace file instead of looking it up.

       -x VAL
           Cross-compile using this toolchain.

MORE HELP

       Use `dune COMMAND --help' for help on a single command.

EXIT STATUS

       dune fmt exits with:

       0   on success.

       1   if an error happened.

       130 if it was interrupted by a signal.

ENVIRONMENT

       These environment variables affect the execution of fmt:

       CLICOLOR
           If different than 0, ANSI colors are supported and should be used when the program
           isn't piped. If equal to 0, don't output ANSI color escape codes

       CLICOLOR_FORCE
           If different than 0, ANSI colors should be enabled no matter what.

       DUNE_BUILD_DIR
           Specified build directory. _build if unspecified

       DUNE_CACHE
           Enable or disable Dune cache (either enabled or disabled). Default is `disabled'.

       DUNE_CACHE_CHECK_PROBABILITY
           Check build reproducibility by re-executing randomly chosen rules and comparing their
           results with those stored in Dune cache. Note: by increasing the probability of such
           checks you slow down the build. The default probability is zero, i.e. no rules are
           checked.

       DUNE_CACHE_ROOT
           If set, determines the location of the machine-global shared cache.

       DUNE_CACHE_STORAGE_MODE
           Dune cache storage mode (one of auto, hardlink or copy). Default is `auto'.

       DUNE_DIFF_COMMAND
           Shell command to use to diff files. Use - to disable printing the diff.

       DUNE_DISABLE_PROMOTION
           Disable all promotion rules

       DUNE_INSTRUMENT_WITH
           Enable instrumentation by BACKENDS. BACKENDS is a comma-separated list of library
           names, each one of which must declare an instrumentation backend.

       DUNE_PROFILE
           Build profile. dev if unspecified or release if -p is set.

       DUNE_SANDBOX
           Sandboxing mode to use by default. (see --sandbox)

       DUNE_STORE_ORIG_SOURCE_DIR
           Store original source location in dune-package metadata.

       DUNE_WORKSPACE
           Use this specific workspace file instead of looking it up.

BUGS

       Check bug reports at https://github.com/ocaml/dune/issues

SEE ALSO

       dune(1)