Provided by: opam-doc_2.1.5-1_all bug

NAME

       opam-clean - Cleans up opam caches

SYNOPSIS

       opam clean [OPTION]…

DESCRIPTION

       Cleans up opam caches, reclaiming some disk space. If no options are specified, the
       default is --logs --download-cache --switch-cleanup.

OPTIONS

       -a, --all-switches
           Run the switch cleanup commands in all switches. Implies --switch-cleanup

       -c, --download-cache
           Clear the cache of downloaded files ($OPAMROOT/download-cache), as well as the
           obsolete $OPAMROOT/archives, if that exists.

       --dry-run
           Print the removal commands, but don't execute them

       --logs
           Clear the logs directory.

       --no
           Answer no to all opam yes/no questions without prompting. See also --confirm-level.
           This is equivalent to setting $OPAMNO to "true".

       -r, --repo-cache
           Clear the repository cache. It will be rebuilt by the next opam command that needs it.

       -s, --switch-cleanup
           Run the switch-specific cleanup: clears backups, build dirs, uncompressed package
           sources of non-dev packages, local metadata of previously pinned packages, etc.

       --unused-repositories
           Clear any configured repository that is not used by any switch nor the default.

       -y, --yes
           Answer yes to all opam yes/no questions without prompting. See also --confirm-level.
           This is equivalent to setting $OPAMYES to "true".

COMMON OPTIONS

       These options are common to all commands.

       --best-effort
           Don't fail if all requested packages can't be installed: try to install as many as
           possible. Note that not all external solvers may support this option (recent versions
           of aspcud or mccs should). This is equivalent to setting $OPAMBESTEFFORT environment
           variable.

       --cli=MAJOR.MINOR (absent=2.1)
           Use the command-line interface syntax and semantics of MAJOR.MINOR. Intended for any
           persistent use of opam (scripts, blog posts, etc.), any version of opam in the same
           MAJOR series will behave as for the specified MINOR release. The flag was not
           available in opam 2.0, so to select the 2.0 CLI, set the OPAMCLI environment variable
           to 2.0 instead of using this parameter.

       --color=WHEN
           Colorize the output. WHEN must be one of always, never or auto.

       --confirm-level=LEVEL
           Confirmation level, LEVEL must be one of ask, no, yes or unsafe-yes. Can be specified
           more than once. If --yes or --no are also given, the value of the last --confirm-level
           is taken into account. This is equivalent to setting  $OPAMCONFIRMLEVEL`.

       --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/External_solvers.html. A
           general guide to using solver preferences can be found at
           http://www.dicosmo.org/Articles/usercriteria.pdf.

       --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 of opam, if set (i.e. you are using a development version), and
           exit.

       --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-pin-depends
           Ignore extra pins required by packages that get pinned, either manually through opam
           pin or through opam install DIR. This is equivalent to setting IGNOREPINDEPENDS=true.

       --json=FILENAME
           Save the results of the opam run in a computer-readable file. If the filename contains
           the character `%', it will be replaced by an index that doesn't overwrite an existing
           file. Similar to setting the $OPAMJSON variable.

       --no-aspcud
           Removed in 2.1.

       --no-auto-upgrade
           When configuring or updating a repository that is written for an earlier opam version
           (1.2), opam internally converts it to the current format. This disables this
           behaviour. Note that repositories should define their format version in a 'repo' file
           at their root, or they will be assumed to be in the older format. It is, in any case,
           preferable to upgrade the repositories manually using opam admin upgrade [--mirror
           URL] when possible.

       --no-self-upgrade
           Opam will replace itself with a newer binary found at OPAMROOT/opam if present. This
           disables this behaviour.

       -q, --quiet
           Disables --verbose.

       --root=ROOT
           Use ROOT as the current root path. This is equivalent to setting $OPAMROOT to ROOT.

       --safe, --readonly
           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. This is equivalent to set environment variable $OPAMSAFE.

       --solver=CMD
           Specify the CUDF solver to use for resolving package installation problems. This is
           either a predefined solver (this version of opam supports builtin-mccs+lp(),
           builtin-mccs+glpk, builtin-dummy-z3-solver, builtin-dummy-0install-solver, aspcud,
           mccs, aspcud-old, packup), or a custom command that should contain the variables
           %{input}%, %{output}%, %{criteria}%, and optionally %{timeout}%. This is equivalent to
           setting $OPAMEXTERNALSOLVER.

       --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
           Disable any external solver, and use the built-in one (this requires that opam has
           been compiled with a built-in solver). This is equivalent to setting $OPAMNOASPCUD or
           $OPAMUSEINTERNALSOLVER.

       -v, --verbose
           Be more verbose. One -v shows all package commands, repeat to also display commands
           called internally (e.g. tar, curl, patch etc.) Repeating n times is equivalent to
           setting $OPAMVERBOSE to "n".

       --version
           Show version information.

       -w, --working-dir
           Whenever updating packages that are bound to a local, version-controlled directory,
           update to the current working state of their source instead of the last committed
           state, or the ref they are pointing to. As source directory is copied as it is, if it
           isn't clean it may result on a opam build failure.This only affects packages
           explicitly listed on the command-line.It can also be set with $OPAMWORKINGDIR.

ENVIRONMENT

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

       OPAMALLPARENS surround all filters with parenthesis.

       OPAMASSUMEDEPEXTS see option `--assume-depexts'.

       OPAMAUTOREMOVE see remove option `--auto-remove'.

       OPAMBESTEFFORT see option `--best-effort'.

       OPAMBESTEFFORTPREFIXCRITERIA sets the string that must be prepended to the criteria when
       the `--best-effort' option is set, and is expected to maximise the `opam-query' property
       in the solution.

       OPAMBUILDDOC Removed in 2.1.

       OPAMBUILDTEST Removed in 2.1.

       OPAMCLI see option `--cli'.

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

       OPAMCONFIRMLEVEL see option `--confirm-level`. OPAMCONFIRMLEVEL has priority over OPAMYES
       and OPAMNO.

       OPAMCRITERIA specifies user preferences for dependency solving. The default value depends
       on the solver version, use `config report' to know the current setting. See also option
       --criteria.

       OPAMCUDFFILE save the cudf graph to file-actions-explicit.dot.

       OPAMCUDFTRIM controls the filtering of unrelated packages during CUDF preprocessing.

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

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

       OPAMDEBUGSECTIONS if set, limits debug messages to the space-separated list of sections.
       Sections can optionally have a specific debug level (for example, CLIENT:2 or CLIENT
       CUDF:2), but otherwise use `--debug-level'.

       OPAMDIGDEPTH defines how aggressive the lookup for conflicts during CUDF preprocessing is.

       OPAMDOWNLOADJOBS sets the maximum number of simultaneous downloads.

       OPAMDROPWORKINGDIR overrides packages previously updated with --working-dir on update.
       Without this variable set, opam would keep them unchanged unless explicitly named on the
       command-line.

       OPAMDRYRUN see option `--dry-run'.

       OPAMEDITOR sets the editor to use for opam file editing, overrides $EDITOR and $VISUAL.

       OPAMERRLOGLEN sets the number of log lines printed when a sub-process fails. 0 to print
       all.

       OPAMEXTERNALSOLVER see option `--solver'.

       OPAMFAKE see option `--fake'.

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

       OPAMFIXUPCRITERIA same as OPAMUPGRADECRITERIA, but specific to fixup.

       OPAMIGNORECONSTRAINTS see install option `--ignore-constraints-on'.

       OPAMIGNOREPINDEPENDS see option `--ignore-pin-depends'.

       OPAMINPLACEBUILD see option `--inplace-build'.

       OPAMJOBS sets the maximum number of parallel workers to run.

       OPAMJSON log json output to the given file (use character `%' to index the files).

       OPAMKEEPBUILDDIR see install option `--keep-build-dir'.

       OPAMKEEPLOGS tells opam to not remove some temporary command logs and some backups. This
       skips some finalisers and may also help to get more reliable backtraces.

       OPAMLOCKED combination of `--locked' and `--lock-suffix' options.

       OPAMLOGS logdir sets log directory, default is a temporary directory in /tmp

       OPAMMAKECMD set the system make command to use.

       OPAMMERGEOUT merge process outputs, stderr on stdout.

       OPAMNO answer no to any question asked, see options `--no` and `--confirm-level`. OPAMNO
       is ignored if either OPAMCONFIRMLEVEL or OPAMYES is set.

       OPAMNOAGGREGATE with `opam admin check', don't aggregate packages.

       OPAMNOASPCUD Deprecated.

       OPAMNOAUTOUPGRADE disables automatic internal upgrade of repositories in an earlier format
       to the current one, on 'update' or 'init'.

       OPAMNOCHECKSUMS enables option --no-checksums when available.

       OPAMNODEPEXTS disables system dependencies handling, see option `--no-depexts'.

       OPAMNOENVNOTICE Internal.

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

       OPAMPINKINDAUTO sets whether version control systems should be detected when pinning to a
       local path. Enabled by default since 1.3.0.

       OPAMPRECISETRACKING fine grain tracking of directories.

       OPAMPREPRO set this to false to disable CUDF preprocessing. Less efficient, but might help
       debugging solver issue.

       OPAMREQUIRECHECKSUMS Enables option `--require-checksums' when available (e.g. for `opam
       install').

       OPAMRETRIES sets the number of tries before failing downloads.

       OPAMREUSEBUILDDIR see option `--reuse-build-dir'.

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

       OPAMROOTISOK don't complain when running as root.

       OPAMSAFE see option `--safe'.

       OPAMSHOW see option `--show'.

       OPAMSKIPUPDATE see option `--skip-updates'.

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

       OPAMSOLVERALLOWSUBOPTIMAL (default `true') allows some solvers to still return a solution
       when they reach timeout; while the solution remains assured to be consistent, there is no
       guarantee in this case that it fits the expected optimisation criteria. If `true', opam
       willcontinue with a warning, if `false' a timeout is an error. Currently only the
       builtin-z3 backend handles this degraded case.

       OPAMSOLVERTIMEOUT change the time allowance of the solver. Default is 60.0, set to 0 for
       unlimited. Note that all solvers may not support this option.

       OPAMSTATS display stats at the end of command.

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

       OPAMSTRICT fail on inconsistencies (file reading, switch import, etc.).

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

       OPAMUNLOCKBASE see install option `--unlock-base'.

       OPAMUPGRADECRITERIA specifies user preferences for dependency solving when performing an
       upgrade. Overrides OPAMCRITERIA in upgrades if both are set. See also option --criteria.

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

       OPAMUSEOPENSSL force openssl use for hash computing.

       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.

       OPAMVALIDATIONHOOK if set, uses the `%{hook%}' command to validate an opam repository
       update.

       OPAMVERBOSE see option `--verbose'.

       OPAMVERSIONLAGPOWER do not use.

       OPAMWITHDOC see install option `--with-doc'.

       OPAMWITHTEST see install option `--with-test.

       OPAMWORKINGDIR see option `--working-dir'.

       OPAMYES see options `--yes' and `--confirm-level`. OPAMYES has has priority over OPAMNO
       and is ignored if OPAMCONFIRMLEVEL is set.

       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.

CLI VERSION

       All scripts and programmatic invocations of opam should use `--cli' in order to ensure
       that they work seamlessly with future versions of the opam client. Additionally, blog
       posts or other documentation can benefit, as it prevents information from becoming stale.

       Although opam only supports roots (~/.opam/) for the current version, it does provide
       backwards compatibility for its command-line interface.

       Since CLI version support was only added in opam 2.1, use OPAMCLI to select 2.0 support
       (as opam 2.0 will just ignore it), and `--cli=2.1' for 2.1 (or later) versions, since an
       environment variable controlling the parsing of syntax is brittle. To this end, opam
       displays a warning if OPAMCLI specifies a valid version other than 2.0, and also if
       `--cli=2.0' is specified.

       The command-line version is selected by using the `--cli' option or the OPAMCLI
       environment variable. `--cli' may be specified morethan once, where the last instance
       takes precedence. OPAMCLI is only inspected if `--cli' is not given.

EXIT STATUS

       As an exception to the following, the `exec' command returns 127 if the command was not
       found or couldn't be executed, and the command's exit value otherwise.

       0   Success, or true for boolean queries.

       1   False. Returned when a boolean return value is expected, e.g. when running with
           --check, or for queries like opam lint.

       2   Bad command-line arguments, or command-line arguments pointing to an invalid context
           (e.g. file not following the expected format).

       5   Not found. You requested something (package, version, repository, etc.) that couldn't
           be found.

       10  Aborted. The operation required confirmation, which wasn't given.

       15  Could not acquire the locks required for the operation.

       20  There is no solution to the user request. This can be caused by asking to install two
           incompatible packages, for example.

       30  Error in package definition, or other metadata files. Using --strict raises this error
           more often.

       31  Package script error. Some package operations were unsuccessful. This may be an error
           in the packages or an incompatibility with your system. This can be a partial error.

       40  Sync error. Could not fetch some remotes from the network. This can be a partial
           error.

       50  Configuration error. Opam or system configuration doesn't allow operation, and needs
           fixing.

       60  Solver failure. The solver failed to return a sound answer. It can be due to a broken
           external solver, or an error in solver configuration.

       99  Internal error. Something went wrong, likely due to a bug in opam itself.

       130 User interrupt. SIGINT was received, generally due to the user pressing Ctrl-C.

FURTHER DOCUMENTATION

       See https://opam.ocaml.org/doc.

AUTHORS

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

BUGS

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