DUNE-EXEC(1) Dune Manual DUNE-EXEC(1)

dune-exec - Execute a command in a similar environment as if installation was performed.

dune exec [OPTION]… PROG [ARGS]…

dune exec -- COMMAND should behave in the same way as if you do:

  $ dune install
  $ COMMAND

In particular if you run dune exec ocaml, you will have access to the libraries defined in the workspace using your usual directives (#require for instance)

When a leading / is present in the command (absolute path), then the path is interpreted as an absolute path

When a / is present at any other position (relative path), then the path is interpreted as relative to the build context + current working directory (or the value of --root when ran outside of the project root)

--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.
--context=CONTEXT (absent=default)
Run the command in this build context.
--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.
--no-build
don't rebuild target before executing
--passive-watch-mode
Similar to [--watch], but only start a build when instructed externally by an RPC.
--react-to-insignificant-changes
React to insignificant file system changes; this is only useful for benchmarking dune.
--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.

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
--debug-store-digest-preimage
Store digest preimage for all computed digests, so that it's possible to reverse them later, for debugging. The digests are stored in the shared cache (see --cache flag) as values, even if cache is otherwise disabled. This should be used only for debugging, since it's slow and it litters the shared cache.
--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.

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

dune exec exits with:

0
on success.
1
if an error happened.
130
if it was interrupted by a signal.

These environment variables affect the execution of exec:

Specified build directory. _build if unspecified
Enable or disable Dune cache (either enabled or disabled). Default is `disabled'.
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 storage mode (one of auto, hardlink or copy). Default is `auto'.
Shell command to use to diff files. Use - to disable printing the diff.
Disable all promotion rules
Enable instrumentation by BACKENDS. BACKENDS is a comma-separated list of library names, each one of which must declare an instrumentation backend.
Build profile. dev if unspecified or release if -p is set.
Sandboxing mode to use by default. (see --sandbox)
Store original source location in dune-package metadata.
Use this specific workspace file instead of looking it up.

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

dune(1)

1.
Run the executable named `my_exec':

      dune exec my_exec
2.
Run the executable defined in `foo.ml' with the argument `arg':

      dune exec -- ./foo.exe arg
Dune 3.14.0