opam-switch - Online in the Cloud

PROGRAM:

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 <[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]>

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