Provided by: opam-doc_2.0.3-1_all bug


       opam-config - Display configuration options for packages.


       opam config [OPTION]... [COMMAND] [ARG]...


       This command uses opam state to output information on how to use installed libraries,
       update the PATH, and substitute variables used in opam packages.

       Apart from opam config env, most of these commands are used by opam internally, and are of
       limited interest for the casual user.


       env Returns the bindings for the environment variables set in the current switch, e.g.
           PATH, in a format intended to be evaluated by a shell. With -v, add comments
           documenting the reason or package of origin for each binding. This is most usefully
           used as eval $(opam config env) to have further shell commands be evaluated in the
           proper opam context. Can also be accessed through opam env.

           Reverts environment changes made by opam, e.g. eval $(opam config revert-env) undoes
           what eval $(opam config env) did, as much as possible.

       exec [--] COMMAND [ARG]...
           Execute COMMAND with the correct environment variables. This command can be used to
           cross-compile between switches using opam config exec --switch=SWITCH -- COMMAND ARG1
           ... ARGn. Opam expansion takes place in command and args. If no switch is present on
           the command line or in the OPAMSWITCH environment variable, OPAMSWITCH is not set in
           COMMAND's environment. Can also be accessed through opam exec.

       var VAR
           Return the value associated with variable VAR. Package variables can be accessed with
           the syntax pkg:var. Can also be accessed through opam var

       list [PACKAGE]...
           Without argument, prints a documented list of all available variables. With PACKAGE,
           lists all the variables available for these packages. Use - to include global
           configuration variables for this switch.

       set VAR VALUE
           Set the given opam variable for the current switch. Warning: changing a configured
           path will not move any files! This command does not perform any variable expansion.

       unset VAR
           Unset the given opam variable for the current switch. Warning: unsetting built-in
           configuration variables can cause problems!

       set-global VAR VALUE
           Set the given variable globally in the opam root, to be visible in all switches

       unset-global VAR
           Unset the given global variable

       expand STRING
           Expand variable interpolations in the given string

       subst FILE...
           Substitute variables in the given files. The strings %{var}% are replaced by the value
           of variable var (see var).

           Prints a summary of your setup, useful for bug-reports.

       cudf-universe [FILE]
           Outputs the current available package universe in CUDF format.

       pef-universe [FILE]
           Outputs the current package universe in PEF format.


           When updating the PATH variable, replace any pre-existing opam path in-place rather
           than putting the new path in front. This means programs installed in opam that were
           shadowed will remain so after opam env

           With the env and exec subcommands, also sets the OPAMROOT variable, making sure
           further calls to opam will use the same root.

           With the env and exec subcommands, also sets the OPAMSWITCH variable, making sure
           further calls to opam will use the same switch as this one.

           Print environment as an s-expression rather than in shell format

           Sets the configuration mode for opam environment appropriate for SHELL. One of one of
           `bash', `sh', `csh', `zsh' or `fish'. Guessed from the parent processes and the $SHELL
           variable by default.


       These options are common to all commands.

           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

           Colorize the output. WHEN must be one of `always', `never' or `auto'.

           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 A
           general guide to using solver preferences can be found at

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

       --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 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.

           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.


           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.

           Opam will replace itself with a newer binary found at OPAMROOT/opam if present. This
           disables this behaviour.

       -q, --quiet
           Disables --verbose.

           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.

           Specify the CUDF solver to use for resolving package installation problems. This is
           either a predefined solver (this version of opam supports builtin-dummy-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.

           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.

           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

       -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".

           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. This only affects packages explicitly listed
           on the command-line.It can also be set with $OPAMWORKINGDIR.

       -y, --yes
           Answer yes to all yes/no questions without prompting. 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", "false" or the empty string to disable, "1", "yes" or "true" to enable.

       OPAMALLPARENS surround all filters with parenthesis

       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

       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 depends
       on the solver version, use `config report` to know the current setting. See also option

       OPAMCUDFFILE file save the cudf graph to

       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.

       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

       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`

       OPAMJOBS sets the maximum number of parallel workers to run.

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

       OPAMLOCKED see install option `--locked`

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

       OPAMMAKECMD set the system make command to use

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

       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

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

       OPAMMERGEOUT merge process outputs, stderr on stdout

       OPAMNO answer no to any question asked.

       OPAMNOASPCUD Deprecated.

       OPAMNOCHECKSUMS enables option --no-checksums when available.

       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

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

       OPAMRETRES sets the number of tries before failing downloads.

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

       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

       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.

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

       OPAMSTATS display stats at the end of command

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

       OPAMSWITCH see option `--switch'. Automatically set by `opam env --switch=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 hook if set, uses the `%{hook%}` command to validate an opam repository

       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'.

       OPAMWORKINGDIR see option `--working-dir`

       OPAMYES see option `--yes'.


       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

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

       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.




       Vincent Bernardoff <>
       Raja Boujbel <>
       Roberto Di Cosmo <>
       Thomas Gazagnaire <>
       Louis Gesbert <>
       Fabrice Le Fessant <>
       Anil Madhavapeddy <>
       Guillem Rieu <>
       Ralf Treinen <>
       Frederic Tuong <>


       Check bug reports at