opam-install(1) Install a list of packages.


opam install [OPTION]... PACKAGES...


This command installs one or more packages to the currently selected compiler. To install packages for another compiler, you need to switch compilers using opam switch. You can remove installed packages with opam remove, and list installed packages with opam list -i. See opam pin as well to understand how to manage package versions.

This command makes OPAM use the dependency solver to compute the transitive closure of dependencies to be installed, and will also handle conflicts. If the dependency solver returns more than one solution, OPAM will arbitrarily select the first one. If dependencies are to be installed, OPAM will confirm if the installation should proceed.


List of package names, with an optional version or constraint, e.g `pkg', `pkg.1.0' or `pkg>=0.5'.


-b, --keep-build-dir
Keep the build directory. This is equivalent to setting $OPAMKEEPBUILDDIR to "true".
-d, --build-doc
Build the package documentation. This is equivalent to setting $OPAMBUILDDOC to "true".
Install all its dependencies, but don't actually install the package.
Simulate the command, but don't actually perform any changes.
-e TAGS, --external=TAGS
Display the external packages associated to the given tags.
This option registers the actions into the OPAM database, without actually performing them. WARNING: This option is dangerous and likely to break your OPAM environment. You probably want `--dry-run'. You've been warned.
-j JOBS, --jobs=JOBS
Set the maximal number of concurrent jobs to use. You can also set it using the $OPAMJOBS environment variable.
Save the result output of an OPAM run in a computer-readable file
-m MAKE, --make=MAKE
Use MAKE as the default 'make' command.
Do not verify the checksum of downloaded archives.This is equivalent to setting $OPAMNOCHECKSUMS to "true".
Reject the installation of packages that don't provide a checksum for the upstream archives. This is equivalent to setting $OPAMREQUIRECHECKSUMS to "true".
Mark given packages as installed roots. This is the default for newly manually-installed packages.
Call the solver and display the actions. Don't perform any changes.
-t, --build-test
Build and run the package unit-tests. This is equivalent to setting $OPAMBUILDTEST to "true".
Mark given packages as "installed automatically".


These options are common to all commands.

--color=WHEN (absent=auto)
Colorize the output. WHEN must be `always', `never' or `auto'.
Compatibility mode with OPAM 1.0
Specify user preferences for dependency solving for this run. Overrides both $OPAMCRITERIA and $OPAMUPGRADECRITERIA. For details on the supported language, and the external solvers available, see http://opam.ocaml.org/doc/Specifying_Solver_Preferences.html. A general guide to using solver preferences can be found at http://www.dicosmo.org/Articles/usercriteria.pdf. The default value is -count(down),-count(removed),-notuptodate(solution),-count(new) for upgrades, and -count(removed),-notuptodate(request),-count(down),-notuptodate(changed),-count(changed),-notuptodate(solution) otherwise.
Debug option: Save the CUDF requests sent to the solver to FILENAME-<n>.cudf.
Print debug message to stderr. This is equivalent to setting $OPAMDEBUG to "true".
Like `--debug', but allows specifying the debug level (`--debug' sets it to 1). Equivalent to setting $OPAMDEBUG to a positive integer.
Print the git version if it exists and exit.
--help[=FMT] (default=pager)
Show this help in format FMT (pager, plain or groff).
Do not install base packages (useful for testing purposes). This is equivalent to setting $OPAMNOBASEPACKAGES to a non-empty string.
OPAM will replace itself with a newer binary found at OPAMROOT/opam if present. This disables this behaviour.
-q, --quiet
Be quiet when installing a new compiler.
--root=ROOT (absent=~/.opam)
Use ROOT as the current root path. This is equivalent to setting $OPAMROOT to ROOT.
Make sure nothing will be automatically updated or rewritten. Useful for calling from completion scripts, for example. Will fail whenever such an operation is needed ; also avoids waiting for locks, skips interactive questions and overrides the OPAMDEBUG variable.
Specify the name of the external dependency solver. The default value is aspcud
Fail whenever an error is found in a package definition or a configuration file. The default is to continue silently if possible.
Use SWITCH as the current compiler switch. This is equivalent to setting $OPAMSWITCH to SWITCH.
--use-internal-solver, --no-aspcud
Force use of internal heuristics, even if an external solver is available.
-v, --verbose
Be more verbose. Show output of all sub-commands. This is equivalent to setting $OPAMVERBOSE to "true".
Show version information.
-y, --yes
Disable interactive mode and answer yes to all questions that would otherwise be asked to the user. This is equivalent to setting $OPAMYES to "true".


OPAM makes use of the environment variables listed here. Boolean variables should be set to "0", "no" of "false" to disable, "1", "yes" or "true" to enable.

OPAMCOLOR, when set to always or never, sets a default value for the --color option.

OPAMCRITERIA specifies user preferences for dependency solving.The default value is -count(removed),-notuptodate(request),-count(down),-notuptodate(changed),-count(changed),-notuptodate(solution). See also option --criteria

OPAMCURL can be used to define an alternative for the 'curl' command-line utility to download files.

OPAMDEBUG see options `--debug' and `--debug-level'.

OPAMEXTERNALSOLVER see option `--solver'.

OPAMJOBS sets the maximum number of parallel workers to run.

OPAMNOASPCUD see option `--no-aspcud'.

OPAMNOSELFUPGRADE see option `--no-self-upgrade'.

OPAMROOT see option `--root'. This is automatically set by `opam config env --root=DIR' when DIR is non-default.

OPAMSOLVERTIMEOUT change the time allowance of the internal solver.

OPAMSWITCH see option `--switch'. Automatically set by `opam config env --switch=SWITCH'.

OPAMUPGRADECRITERIA specifies user preferences for dependency solving when performing an upgrade. Overrides OPAMCRITERIA in upgrades if both are set.The default value is -count(down),-count(removed),-notuptodate(solution),-count(new). See also option --criteria

OPAMUTF8MSGS use nice UTF8 characters in OPAM messages.

OPAMVERBOSE see option `--verbose'.

OPAMVAR_var overrides the contents of the variable var when substituting `%{var}%` strings in `opam` files.

OPAMVAR_package_var overrides the contents of the variable package:var when substituting `%{package:var}%` strings in `opam` files.

OPAMUSEINTERNALSOLVER see option `--use-internal-solver'.

OPAMYES see option `--yes'.


See https://opam.ocaml.org.


Thomas Gazagnaire <[email protected]>

Anil Madhavapeddy <[email protected]>

Fabrice Le Fessant <[email protected]>

Frederic Tuong <[email protected]>

Louis Gesbert <[email protected]>

Vincent Bernardoff <[email protected]>

Guillem Rieu <[email protected]>

Roberto Di Cosmo <[email protected]>


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