The global configuration file for
cabal-install is by default
$XDG_CONFIG_HOME/cabal/config. If you do not have this file,
cabal will create
it for you on the first call to
(details see configuration file discovery).
Alternatively, you can explicitly ask
cabal to create it for you using
$ cabal user-config update
You can change the location of the global configuration file by specifying
--config-file=FILE on the command line or by setting the
CABAL_DIR environment variable.
Most of the options in this configuration file are also available as command line arguments, and the corresponding documentation can be used to lookup their meaning. The created configuration file only specifies values for a handful of options. Most options are left at their default value, which it documents; for instance,
-- executable-stripping: True
means that the configuration file currently does not specify a value for
executable-stripping option (the line is commented out), and
that the default is
True; if you wanted to disable stripping of
executables by default, you would change this line to
You can also use
cabal user-config update to migrate configuration
files created by older versions of
5.1.2. Environment variables
Various environment variables affect
The variable to find global configuration file.
If set, all
cabal-installcontent files will be stored as subdirectories of this directory, including the configuration file if
CABAL_CONFIGis unset. If
CABAL_DIRis unset, Cabal will store data files according to the XDG Base Directory Specification (see directories).
For backwards compatibility, if the directory
~/.cabalon Unix or
%APPDATA%\cabalon Windows exist and
cabal-installwill behave as if
CABAL_DIRwas set to point at this directory.
The override for default
distbuild directory. Note, the nix-style builds build directory (
dist-newstyle) is not affected by this environment variable.
188.8.131.52. Configuration file discovery
The configuration file location is determined as follows:
--config-fileis given, use it;
$CABAL_CONFIGis set use it;
$CABAL_DIRis set use
$XDG_CONFIG_HOME/cabal, which defaults to
If the configuration file does not exist, and it was not given
cabal-install will generate the default one, with directories
$CABAL_DIR (if set) or according to the XDG Base
Directory Specification, as listed below.
CABAL_DIR environment variable is set or a
directory exists, Cabal will by default store data in directories
according to the XDG Base Directory Specification. The following
directories are used unless otherwise specified in the configuration
$XDG_CONFIG_HOME/cabalfor the main configuration file. Defaults to
~/.config/cabalon Unix, and
%APPDATA%/cabalon Windows. Overridden by the
CABAL_CONFIGenvironment variable if set.
$XDG_CACHE_HOME/cabalfor downloaded packages and script executables. Defaults to
~/.cache/cabalon Unix, and
%LOCALAPPDATA%/cabalon Windows. You can delete this directory and expect that its contents will be reconstructed as needed.
$XDG_STATE_HOME/cabalfor compiled libraries and other stateful artifacts, including the Cabal store. Defaults to
~/.local/state/cabalon Unix and
%LOCALAPPDATA%/cabalon Windows. Deleting this directory might cause installed programs to stop working.
~/.local/binfor executables installed with
5.1.4. Repository specification
An important part of the configuration is the specification of the
cabal creates a default config file, it configures
the repository to be the central Hackage server:
repository hackage.haskell.org url: http://hackage.haskell.org/
The name of the repository is given on the first line, and can be
anything; packages downloaded from this repository will be cached under
$XDG_CACHE_HOME/cabal/packages/hackage.haskell.org (or whatever name you specify;
you can change the prefix by changing the value of
remote-repo-cache). If you want, you can configure multiple
cabal will combine them and be able to download
packages from any of them.
184.108.40.206. Using secure repositories
When interacting with
hackage.haskell.org, Cabal always runs in secure mode
with standard root keys, so it is not necessary to specify
root-keys. If no repositories are listed, Cabal will default to
For non-Hackage repositories that support the TUF security infrastructure you can enable secure access to the repository by specifying:
repository packages.example.org url: http://packages.example.org/ secure: True root-keys: <root-key-IDs> key-threshold: <key-threshold>
<key-threshold> values are used for
bootstrapping. As part of the TUF infrastructure the repository will
contain a file
root.json (for instance,
http://hackage.haskell.org/root.json) which the client needs to do
verification. However, how can
cabal verify the
itself? This is known as bootstrapping: if you specify a list of root
key IDs and a corresponding threshold,
cabal will verify that the
root.json file has been signed with at least
<key-threshold> keys from your set of
You can, but are not recommended to, omit these two fields. In that case
cabal will download the
root.json field and use it without
verification. Although this bootstrapping step is then unsafe, all
subsequent access is secure (provided that the downloaded
was not tampered with). Of course, adding
key-threshold to your repository specification only shifts the
problem, because now you somehow need to make sure that the key IDs you
received were the right ones. How that is done is however outside the
More information about the security infrastructure can be found at https://github.com/haskell/hackage-security.
220.127.116.11. Local no-index repositories
It’s possible to use a directory of .tar.gz package files as a local package repository.
repository my-local-repository url: file+noindex:///absolute/path/to/directory
cabal will construct the index automatically from the
package-name-version.tar.gz files in the directory, and will use optional
package-name-version.cabal files as new revisions.
For example, if
/absolute/path/to/directory looks like
/absolute/path/to/directory/ foo-0.1.0.0.tar.gz bar-0.2.0.0.tar.gz bar-0.2.0.0.cabal
cabal will create an index with two packages:
foo-0.1.0.0using the source and
bar-0.2.0.0using the source inside
The index is cached inside the given directory. If the directory is not
writable, you can append
#shared-cache fragment to the URI,
then the cache will be stored inside the
The part of the path will be used to determine the cache key part.
cabal-install creates a
.cache file, and will aggressively use
its contents if it exists. Therefore if you change the contents of
the directory, remember to wipe the cache too.
The URI scheme
file: is interpreted as a remote repository,
as described in the previous sections, thus requiring manual construction
It is possible to define
preferred-versions, containing additional version constraints
for deprecating or preferring certain package versions, in the given directory.
For example, if
/absolute/path/to/directory looks like
/absolute/path/to/directory/ foo-0.1.0.0.tar.gz bar-0.2.0.0.tar.gz preferred-versions
then package deprecations and preferences will be taken into account by the solver.
The contents of
preferred-versions is a list of package version constraints, e.g.
binary < 0.8.0.0 || > 0.8.0.0 text == 18.104.22.168
thus, looks similar to a
preferred-versions file can be used to restrict the package set from Hackage, by preferring
certain versions or marking a specific version as deprecated. To achieve this, add a
local no-index repository to your configuration file,
where the directory contains your custom
preferred-versions. After running
cabal update, all
cabal operations will honour the
22.214.171.124. Legacy repositories
cabal supports single kind of “legacy” repositories.
It is specified using
This is just syntactic sugar for
repository hackage.haskell.org url: http://hackage.haskell.org/packages/archive
although, in (and only in) the specific case of Hackage, the URL
http://hackage.haskell.org/packages/archive will be silently
126.96.36.199. Secure local repositories
If you want to use repositories on your local file system, it is recommended instead to use a secure local repository:
repository my-local-repo url: file:/path/to/local/repo secure: True root-keys: <root-key-IDs> key-threshold: <key-threshold>
The layout of these secure local repos matches the layout of remote repositories exactly; the hackage-repo-tool can be used to create and manage such repositories.