opam --help

NAME
       opam - source-based OCaml package management

SYNOPSIS
       opam COMMAND ...

DESCRIPTION
       OPAM is a package manager for OCaml. It uses the powerful mancoosi
       tools to handle dependencies, including support for version
       constraints, optional dependencies, and conflict management.

       It has support for different remote repositories such as HTTP, rsync,
       git, darcs and mercurial. It handles multiple OCaml versions
       concurrently, and is flexible enough to allow you to use your own
       repositories and packages in addition to the central ones it provides.

       Use either opam <command> --help or opam help <command> for more
       information on a specific command.

COMMAND ALIASES
       info
           An alias for show.

       remote
           An alias for repository.

       uninstall
           An alias for remove.

       unpin
           An alias for pin remove.

COMMANDS
       config
           Display configuration options for packages.

       help
           Display help about OPAM and OPAM commands.

       init
           Initialize OPAM state.

       install
           Install a list of packages.

       lint
           Checks and validate package description ('opam') files.

       list
           Display the list of available packages.

       pin Pin a given package to a specific version or source.

       reinstall
           Reinstall a list of packages.

       remove
           Remove a list of packages.

       repository
           Manage OPAM repositories.

       search
           Search into the package list.

       show
           Display information about specific packages.

       source
           Get the source of an OPAM package.

       switch
           Manage multiple installation of compilers.

       update
           Update the list of available packages.

       upgrade
           Upgrade the installed package to latest version.

COMMON OPTIONS
       These options are common to all commands.

       --color=WHEN (absent=auto)
           Colorize the output. WHEN must be one of `always', `never' or
           `auto'.

       --criteria=CRITERIA
           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),-sum(solution,version-lag),-count(new)
           for upgrades, and
           -count(removed),-notuptodate(request),-sum(request,version-lag),-count(down),-notuptodate(changed),-count(changed),-notuptodate(solution),-sum(solution,version-lag)
           otherwise.

       --cudf=FILENAME
           Debug option: Save the CUDF requests sent to the solver to
           FILENAME-<n>.cudf.

       --debug
           Print debug message to stderr. This is equivalent to setting
           $OPAMDEBUG to "true".

       --debug-level=LEVEL
           Like `--debug', but allows specifying the debug level (`--debug'
           sets it to 1). Equivalent to setting $OPAMDEBUG to a positive
           integer.

       --git-version
           Print the git version if it exists and exit.

       --help[=FMT] (default=pager)
           Show this help in format FMT (pager, plain or groff).

       --no-base-packages
           Do not install base packages (useful for testing purposes). This
           is equivalent to setting $OPAMNOBASEPACKAGES to a non-empty
           string.

       --no-self-upgrade
           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.

       --safe
           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.

       --solver=CMD
           Specify the name of the external dependency solver. The default
           value is aspcud. Either 'aspcud', 'packup' or a custom command
           that may contain the variables %{input}%, %{output}% and
           %{criteria}%

       --strict
           Fail whenever an error is found in a package definition or a
           configuration file. The default is to continue silently if
           possible.

       --switch=SWITCH
           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 package sub-commands and their output.
           Repeat to see more. Repeating n times is equivalent to setting
           $OPAMVERBOSE to "n".

       --version
           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".

ENVIRONMENT VARIABLES
       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),-sum(request,version-lag),-count(down),-notuptodate(changed),-count(changed),-notuptodate(solution),-sum(solution,version-lag).
       See also option --criteria

       OPAMCURL can be used to select a given 'curl' program. See OPAMFETCH
       for more options.

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

       OPAMDOWNLOADJOBS sets the maximum number of simultaneous downloads.

       OPAMEXTERNALSOLVER see option `--solver'.

       OPAMFETCH specifies how to download files: either `wget', `curl' or a
       custom command where variables %{url}%, %{out}%, %{retries}%,
       %{compress}% and %{checksum}% will be replaced. Overrides the
       'download-command' value from the main config file.

       OPAMJOBS sets the maximum number of parallel workers to run.

       OPAMLOCKRETRIES sets the number of tries after which OPAM gives up
       acquiring its lock and fails. <= 0 means infinite wait.

       OPAMNO answer no to any question asked.

       OPAMNOASPCUD see option `--no-aspcud'.

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

       OPAMPINKINDAUTO if set, version control systems are detected when
       pinning to a local path.

       OPAMREQUIRECHECKSUMS see option `--require-checksums'.

       OPAMRETRY sets the number of tries before failing downloads.

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

       OPAMSAFE see option `--safe'

       OPAMSKIPVERSIONCHECKS bypasses some version checks. Unsafe, for
       compatibility testing only.

       OPAMSOLVERTIMEOUT change the time allowance of the internal solver.

       OPAMSTATUSLINE display a dynamic status line showing what's currently
       going on on the terminal. (one of one of `always', `never' or `auto')

       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),-sum(solution,version-lag),-count(new).
       See also option --criteria

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

       OPAMUTF8 use UTF8 characters in output (one of one of `always',
       `never' or `auto'). By default `auto', which is determined from the
       locale).

       OPAMUTF8MSGS use extended UTF8 characters (camels) in OPAM messages.
       Implies OPAMUTF8. This is set by default on OSX only.

       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.

       OPAMVERBOSE see option `--verbose'.

       OPAMYES see option `--yes'.

FURTHER DOCUMENTATION
       See https://opam.ocaml.org.

AUTHORS
       Thomas Gazagnaire <thomas@gazagnaire.org>
       Anil Madhavapeddy <anil@recoil.org>
       Fabrice Le Fessant <Fabrice.Le_fessant@inria.fr>
       Frederic Tuong <tuong@users.gforge.inria.fr>
       Louis Gesbert <louis.gesbert@ocamlpro.com>
       Vincent Bernardoff <vb@luminar.eu.org>
       Guillem Rieu <guillem.rieu@ocamlpro.com>
       Roberto Di Cosmo <roberto@dicosmo.org>

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