DragonFly On-Line Manual Pages

OPAM-SWITCH(1)                    Opam Manual                   OPAM-SWITCH(1)

NAME
       opam-switch - Manage multiple installation of compilers.

SYNOPSIS
       opam switch [OPTION]... [COMMAND] [ARG]...

DESCRIPTION
       This command allows one to switch between different compiler versions,
       installing the compiler if opam switch is used to switch to that
       compiler for the first time. The different compiler versions are
       totally independent from each other, meaning that OPAM maintains a
       separate state (e.g. list of installed packages...) for each.

       See the documentation of opam switch list to see the compilers which
       are available, and how to switch or to install a new one.

COMMANDS
       Without argument, defaults to list.

       SWITCH
           With a SWITCH argument, defaults to set SWITCH.

       install SWITCH
           Install the given compiler. The command fails if the switch is
           already installed (e.g. it will not transparently switch to the
           installed compiler switch, as with set).

       set SWITCH
           Set the currently active switch, installing it if needed.

       remove SWITCH
           Remove the given compiler.

       export FILE
           Save the current switch state to a file.

       import FILE
           Import a saved switch state.

       reinstall SWITCH
           Reinstall the given compiler switch. This will also reinstall all
           packages.

       list
           List compilers. By default, lists installed and `standard'
           compilers. Use `--all' to get the list of all installable
           compilers. The first column displays the switch name (if any), the
           second one the switch state (C = current, I = installed, -- = not
           installed), the third one the compiler name and the last one the
           compiler description. To switch to an already installed compiler
           alias (with state = I), use opam switch <name>. If you want to use
           a new compiler <comp>, use opam switch <comp>: this will download,
           compile and create a fresh and independent environment where new
           packages can be installed. If you want to create a new compiler
           alias (for instance because you already have this compiler version
           installed), use opam switch <name> --alias-of <comp>. In case
           <name> and <comp> are the same, this is equivalent to opam switch
           <comp>.

       show
           Show the current compiler.

OPTIONS
       -A COMP, --alias-of=COMP
           The name of the compiler description which will be aliased.

       -a, --all
           List all the compilers which can be installed on the system.

       -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".

       --dry-run
           Simulate the command, but don't actually perform any changes.

       -e TAGS, --external=TAGS
           Display the external packages associated to the given tags. This is
           deprecated, use `opam list --external' instead

       --fake
           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.

       -i, --installed
           List installed compiler switches only.

       -j JOBS, --jobs=JOBS
           Set the maximal number of concurrent jobs to use. You can also set
           it using the $OPAMJOBS environment variable.

       --json=FILENAME
           Save the result output of an OPAM run in a computer-readable file

       -m MAKE, --make=MAKE
           Use MAKE as the default 'make' command.

       --no-checksums
           Do not verify the checksum of downloaded archives.This is
           equivalent to setting $OPAMNOCHECKSUMS to "true".

       --no-switch
           Only install the compiler switch, without switching to it. If the
           compiler switch is already installed, then do nothing.

       --no-warning
           Do not display any warning related to environment variables.

       --require-checksums
           Reject the installation of packages that don't provide a checksum
           for the upstream archives. This is equivalent to setting
           $OPAMREQUIRECHECKSUMS to "true".

       -s, --short
           Output raw lists of names, one per line, skipping any details.

       --show-actions
           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".

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.

Opam 1.2.2                                                      OPAM-SWITCH(1)