guix.texi

@example
guix import gnu hello
@end example

Specific command-line options are:

@table @code
@item --key-download=@var{policy}
As for @code{guix refresh}, specify the policy to handle missing OpenPGP
keys when verifying the package signature.  @xref{Invoking guix
refresh, @code{--key-download}}.
@end table

@item pypi
@cindex pypi
Import metadata from the @uref{https://pypi.python.org/, Python Package
Index}.  Information is taken from the JSON-formatted description
available at @code{pypi.python.org} and usually includes all the relevant
information, including package dependencies.  For maximum efficiency, it
is recommended to install the @command{unzip} utility, so that the
importer can unzip Python wheels and gather data from them.

The command below imports metadata for the @code{itsdangerous} Python
package:

@example
guix import pypi itsdangerous
@end example

@table @code
@item --recursive
@itemx -r
Traverse the dependency graph of the given upstream package recursively
and generate package expressions for all those packages that are not yet
in Guix.
@end table

@item gem
@cindex gem
Import metadata from @uref{https://rubygems.org/, RubyGems}.  Information
is taken from the JSON-formatted description available at
@code{rubygems.org} and includes most relevant information, including
runtime dependencies.  There are some caveats, however.  The metadata
doesn't distinguish between synopses and descriptions, so the same string
is used for both fields.  Additionally, the details of non-Ruby
dependencies required to build native extensions is unavailable and left
as an exercise to the packager.

The command below imports metadata for the @code{rails} Ruby package:

@example
guix import gem rails
@end example

@table @code
@item --recursive
@itemx -r
Traverse the dependency graph of the given upstream package recursively
and generate package expressions for all those packages that are not yet
in Guix.
@end table

@item cpan
@cindex CPAN
Import metadata from @uref{https://www.metacpan.org/, MetaCPAN}.
Information is taken from the JSON-formatted metadata provided through
@uref{https://fastapi.metacpan.org/, MetaCPAN's API} and includes most
relevant information, such as module dependencies.  License information
should be checked closely.  If Perl is available in the store, then the
@code{corelist} utility will be used to filter core modules out of the
list of dependencies.

The command command below imports metadata for the @code{Acme::Boolean}
Perl module:

@example
guix import cpan Acme::Boolean
@end example

@item cran
@cindex CRAN
@cindex Bioconductor
Import metadata from @uref{https://cran.r-project.org/, CRAN}, the
central repository for the @uref{http://r-project.org, GNU@tie{}R
statistical and graphical environment}.

Information is extracted from the @code{DESCRIPTION} file of the package.

The command command below imports metadata for the @code{Cairo}
R package:

@example
guix import cran Cairo
@end example

When @code{--recursive} is added, the importer will traverse the
dependency graph of the given upstream package recursively and generate
package expressions for all those packages that are not yet in Guix.

When @code{--archive=bioconductor} is added, metadata is imported from
@uref{https://www.bioconductor.org/, Bioconductor}, a repository of R
packages for for the analysis and comprehension of high-throughput
genomic data in bioinformatics.

Information is extracted from the @code{DESCRIPTION} file of a package
published on the web interface of the Bioconductor SVN repository.

The command below imports metadata for the @code{GenomicRanges}
R package:

@example
guix import cran --archive=bioconductor GenomicRanges
@end example

@item texlive
@cindex TeX Live
@cindex CTAN
Import metadata from @uref{http://www.ctan.org/, CTAN}, the
comprehensive TeX archive network for TeX packages that are part of the
@uref{https://www.tug.org/texlive/, TeX Live distribution}.

Information about the package is obtained through the XML API provided
by CTAN, while the source code is downloaded from the SVN repository of
the Tex Live project.  This is done because the CTAN does not keep
versioned archives.

The command command below imports metadata for the @code{fontspec}
TeX package:

@example
guix import texlive fontspec
@end example

When @code{--archive=DIRECTORY} is added, the source code is downloaded
not from the @file{latex} sub-directory of the @file{texmf-dist/source}
tree in the TeX Live SVN repository, but from the specified sibling
directory under the same root.

The command below imports metadata for the @code{ifxetex} package from
CTAN while fetching the sources from the directory
@file{texmf/source/generic}:

@example
guix import texlive --archive=generic ifxetex
@end example

@item json
@cindex JSON, import
Import package metadata from a local JSON file.  Consider the following
example package definition in JSON format:

@example
@{
  "name": "hello",
  "version": "2.10",
  "source": "mirror://gnu/hello/hello-2.10.tar.gz",
  "build-system": "gnu",
  "home-page": "https://www.gnu.org/software/hello/",
  "synopsis": "Hello, GNU world: An example GNU package",
  "description": "GNU Hello prints a greeting.",
  "license": "GPL-3.0+",
  "native-inputs": ["gcc@@6"]
@}
@end example

The field names are the same as for the @code{<package>} record
(@xref{Defining Packages}).  References to other packages are provided
as JSON lists of quoted package specification strings such as
@code{guile} or @code{guile@@2.0}.

The importer also supports a more explicit source definition using the
common fields for @code{<origin>} records:

@example
@{
  @dots{}
  "source": @{
    "method": "url-fetch",
    "uri": "mirror://gnu/hello/hello-2.10.tar.gz",
    "sha256": @{
      "base32": "0ssi1wpaf7plaswqqjwigppsg5fyh99vdlb9kzl7c9lng89ndq1i"
    @}
  @}
  @dots{}
@}
@end example

The command below reads metadata from the JSON file @code{hello.json}
and outputs a package expression:

@example
guix import json hello.json
@end example

@item nix
Import metadata from a local copy of the source of the
@uref{http://nixos.org/nixpkgs/, Nixpkgs distribution}@footnote{This
relies on the @command{nix-instantiate} command of
@uref{http://nixos.org/nix/, Nix}.}.  Package definitions in Nixpkgs are
typically written in a mixture of Nix-language and Bash code.  This
command only imports the high-level package structure that is written in
the Nix language.  It normally includes all the basic fields of a
package definition.

When importing a GNU package, the synopsis and descriptions are replaced
by their canonical upstream variant.

Usually, you will first need to do:

@example
export NIX_REMOTE=daemon
@end example

@noindent
so that @command{nix-instantiate} does not try to open the Nix database.

As an example, the command below imports the package definition of
LibreOffice (more precisely, it imports the definition of the package
bound to the @code{libreoffice} top-level attribute):

@example
guix import nix ~/path/to/nixpkgs libreoffice
@end example

@item hackage
@cindex hackage
Import metadata from the Haskell community's central package archive
@uref{https://hackage.haskell.org/, Hackage}.  Information is taken from
Cabal files and includes all the relevant information, including package
dependencies.

Specific command-line options are:

@table @code
@item --stdin
@itemx -s
Read a Cabal file from standard input.
@item --no-test-dependencies
@itemx -t
Do not include dependencies required only by the test suites.
@item --cabal-environment=@var{alist}
@itemx -e @var{alist}
@var{alist} is a Scheme alist defining the environment in which the
Cabal conditionals are evaluated.  The accepted keys are: @code{os},
@code{arch}, @code{impl} and a string representing the name of a flag.
The value associated with a flag has to be either the symbol
@code{true} or @code{false}.  The value associated with other keys
has to conform to the Cabal file format definition.  The default value
associated with the keys @code{os}, @code{arch} and @code{impl} is
@samp{linux}, @samp{x86_64} and @samp{ghc}, respectively.
@item --recursive
@itemx -r
Traverse the dependency graph of the given upstream package recursively
and generate package expressions for all those packages that are not yet
in Guix.
@end table

The command below imports metadata for the latest version of the
@code{HTTP} Haskell package without including test dependencies and
specifying the value of the flag @samp{network-uri} as @code{false}:

@example
guix import hackage -t -e "'((\"network-uri\" . false))" HTTP
@end example

A specific package version may optionally be specified by following the
package name by an at-sign and a version number as in the following example:

@example
guix import hackage mtl@@2.1.3.1
@end example

@item stackage
@cindex stackage
The @code{stackage} importer is a wrapper around the @code{hackage} one.
It takes a package name, looks up the package version included in a
long-term support (LTS) @uref{https://www.stackage.org, Stackage}
release and uses the @code{hackage} importer to retrieve its metadata.
Note that it is up to you to select an LTS release compatible with the
GHC compiler used by Guix.

Specific command-line options are:

@table @code
@item --no-test-dependencies
@itemx -t
Do not include dependencies required only by the test suites.
@item --lts-version=@var{version}
@itemx -l @var{version}
@var{version} is the desired LTS release version.  If omitted the latest
release is used.
@item --recursive
@itemx -r
Traverse the dependency graph of the given upstream package recursively
and generate package expressions for all those packages that are not yet
in Guix.
@end table

The command below imports metadata for the @code{HTTP} Haskell package
included in the LTS Stackage release version 7.18:

@example
guix import stackage --lts-version=7.18 HTTP
@end example

@item elpa
@cindex elpa
Import metadata from an Emacs Lisp Package Archive (ELPA) package
repository (@pxref{Packages,,, emacs, The GNU Emacs Manual}).

Specific command-line options are:

@table @code
@item --archive=@var{repo}
@itemx -a @var{repo}
@var{repo} identifies the archive repository from which to retrieve the
information.  Currently the supported repositories and their identifiers
are:
@itemize -
@item
@uref{http://elpa.gnu.org/packages, GNU}, selected by the @code{gnu}
identifier.  This is the default.

Packages from @code{elpa.gnu.org} are signed with one of the keys
contained in the GnuPG keyring at
@file{share/emacs/25.1/etc/package-keyring.gpg} (or similar) in the
@code{emacs} package (@pxref{Package Installation, ELPA package
signatures,, emacs, The GNU Emacs Manual}).

@item
@uref{http://stable.melpa.org/packages, MELPA-Stable}, selected by the
@code{melpa-stable} identifier.

@item
@uref{http://melpa.org/packages, MELPA}, selected by the @code{melpa}
identifier.
@end itemize

@item --recursive
@itemx -r
Traverse the dependency graph of the given upstream package recursively
and generate package expressions for all those packages that are not yet
in Guix.
@end table

@item crate
@cindex crate
Import metadata from the crates.io Rust package repository
@uref{https://crates.io, crates.io}.

@item opam
@cindex OPAM
@cindex OCaml
Import metadata from the @uref{https://opam.ocaml.org/, OPAM} package
repository used by the OCaml community.
@end table

The structure of the @command{guix import} code is modular.  It would be
useful to have more importers for other package formats, and your help
is welcome here (@pxref{Contributing}).

@node Invoking guix refresh
@section Invoking @command{guix refresh}

@cindex @command {guix refresh}
The primary audience of the @command{guix refresh} command is developers
of the GNU software distribution.  By default, it reports any packages
provided by the distribution that are outdated compared to the latest
upstream version, like this:

@example
$ guix refresh
gnu/packages/gettext.scm:29:13: gettext would be upgraded from 0.18.1.1 to 0.18.2.1
gnu/packages/glib.scm:77:12: glib would be upgraded from 2.34.3 to 2.37.0
@end example

Alternately, one can specify packages to consider, in which case a
warning is emitted for packages that lack an updater:

@example
$ guix refresh coreutils guile guile-ssh
gnu/packages/ssh.scm:205:2: warning: no updater for guile-ssh
gnu/packages/guile.scm:136:12: guile would be upgraded from 2.0.12 to 2.0.13
@end example

@command{guix refresh} browses the upstream repository of each package and determines
the highest version number of the releases therein.  The command
knows how to update specific types of packages: GNU packages, ELPA
packages, etc.---see the documentation for @option{--type} below.  There
are many packages, though, for which it lacks a method to determine
whether a new upstream release is available.  However, the mechanism is
extensible, so feel free to get in touch with us to add a new method!

Sometimes the upstream name differs from the package name used in Guix,
and @command{guix refresh} needs a little help.  Most updaters honor the
@code{upstream-name} property in package definitions, which can be used
to that effect:

@example
(define-public network-manager
  (package
    (name "network-manager")
    ;; @dots{}
    (properties '((upstream-name . "NetworkManager")))))
@end example

When passed @code{--update}, it modifies distribution source files to
update the version numbers and source tarball hashes of those package
recipes (@pxref{Defining Packages}).  This is achieved by downloading
each package's latest source tarball and its associated OpenPGP
signature, authenticating the downloaded tarball against its signature
using @command{gpg}, and finally computing its hash.  When the public
key used to sign the tarball is missing from the user's keyring, an
attempt is made to automatically retrieve it from a public key server;
when this is successful, the key is added to the user's keyring; otherwise,
@command{guix refresh} reports an error.

The following options are supported:

@table @code

@item --expression=@var{expr}
@itemx -e @var{expr}
Consider the package @var{expr} evaluates to.

This is useful to precisely refer to a package, as in this example:

@example
guix refresh -l -e '(@@@@ (gnu packages commencement) glibc-final)'
@end example

This command lists the dependents of the ``final'' libc (essentially all
the packages.)

@item --update
@itemx -u
Update distribution source files (package recipes) in place.  This is
usually run from a checkout of the Guix source tree (@pxref{Running
Guix Before It Is Installed}):

@example
$ ./pre-inst-env guix refresh -s non-core -u
@end example

@xref{Defining Packages}, for more information on package definitions.

@item --select=[@var{subset}]
@itemx -s @var{subset}
Select all the packages in @var{subset}, one of @code{core} or
@code{non-core}.

The @code{core} subset refers to all the packages at the core of the
distribution---i.e., packages that are used to build ``everything
else''.  This includes GCC, libc, Binutils, Bash, etc.  Usually,
changing one of these packages in the distribution entails a rebuild of
all the others.  Thus, such updates are an inconvenience to users in
terms of build time or bandwidth used to achieve the upgrade.

The @code{non-core} subset refers to the remaining packages.  It is
typically useful in cases where an update of the core packages would be
inconvenient.

@item --manifest=@var{file}
@itemx -m @var{file}
Select all the packages from the manifest in @var{file}. This is useful to
check if any packages of the user manifest can be updated.

@item --type=@var{updater}
@itemx -t @var{updater}
Select only packages handled by @var{updater} (may be a comma-separated
list of updaters).  Currently, @var{updater} may be one of:

@table @code
@item gnu
the updater for GNU packages;
@item gnome
the updater for GNOME packages;
@item kde
the updater for KDE packages;
@item xorg
the updater for X.org packages;
@item kernel.org
the updater for packages hosted on kernel.org;
@item elpa
the updater for @uref{http://elpa.gnu.org/, ELPA} packages;
@item cran
the updater for @uref{https://cran.r-project.org/, CRAN} packages;
@item bioconductor
the updater for @uref{https://www.bioconductor.org/, Bioconductor} R packages;
@item cpan
the updater for @uref{http://www.cpan.org/, CPAN} packages;
@item pypi
the updater for @uref{https://pypi.python.org, PyPI} packages.
@item gem
the updater for @uref{https://rubygems.org, RubyGems} packages.
@item github
the updater for @uref{https://github.com, GitHub} packages.
@item hackage
the updater for @uref{https://hackage.haskell.org, Hackage} packages.
@item stackage
the updater for @uref{https://www.stackage.org, Stackage} packages.
@item crate
the updater for @uref{https://crates.io, Crates} packages.
@end table

For instance, the following command only checks for updates of Emacs
packages hosted at @code{elpa.gnu.org} and for updates of CRAN packages:

@example
$ guix refresh --type=elpa,cran
gnu/packages/statistics.scm:819:13: r-testthat would be upgraded from 0.10.0 to 0.11.0
gnu/packages/emacs.scm:856:13: emacs-auctex would be upgraded from 11.88.6 to 11.88.9
@end example

@end table

In addition, @command{guix refresh} can be passed one or more package
names, as in this example:

@example
$ ./pre-inst-env guix refresh -u emacs idutils gcc@@4.8
@end example

@noindent
The command above specifically updates the @code{emacs} and
@code{idutils} packages.  The @code{--select} option would have no
effect in this case.

When considering whether to upgrade a package, it is sometimes
convenient to know which packages would be affected by the upgrade and
should be checked for compatibility.  For this the following option may
be used when passing @command{guix refresh} one or more package names:

@table @code

@item --list-updaters
@itemx -L
List available updaters and exit (see @option{--type} above.)

For each updater, display the fraction of packages it covers; at the
end, display the fraction of packages covered by all these updaters.

@item --list-dependent
@itemx -l
List top-level dependent packages that would need to be rebuilt as a
result of upgrading one or more packages.

@xref{Invoking guix graph, the @code{reverse-package} type of
@command{guix graph}}, for information on how to visualize the list of
dependents of a package.

@end table

Be aware that the @code{--list-dependent} option only
@emph{approximates} the rebuilds that would be required as a result of
an upgrade.  More rebuilds might be required under some circumstances.

@example
$ guix refresh --list-dependent flex
Building the following 120 packages would ensure 213 dependent packages are rebuilt:
hop@@2.4.0 geiser@@0.4 notmuch@@0.18 mu@@0.9.9.5 cflow@@1.4 idutils@@4.6 @dots{}
@end example

The command above lists a set of packages that could be built to check
for compatibility with an upgraded @code{flex} package.

The following options can be used to customize GnuPG operation:

@table @code

@item --gpg=@var{command}
Use @var{command} as the GnuPG 2.x command.  @var{command} is searched
for in @code{$PATH}.

@item --keyring=@var{file}
Use @var{file} as the keyring for upstream keys.  @var{file} must be in the
@dfn{keybox format}.  Keybox files usually have a name ending in @file{.kbx}
and the GNU@tie{}Privacy Guard (GPG) can manipulate these files
(@pxref{kbxutil, @command{kbxutil},, gnupg, Using the GNU Privacy Guard}, for
information on a tool to manipulate keybox files).

When this option is omitted, @command{guix refresh} uses
@file{~/.config/guix/upstream/trustedkeys.kbx} as the keyring for upstream
signing keys.  OpenPGP signatures are checked against keys from this keyring;
missing keys are downloaded to this keyring as well (see
@option{--key-download} below.)

You can export keys from your default GPG keyring into a keybox file using
commands like this one:

@example
gpg --export rms@@gnu.org | kbxutil --import-openpgp >> mykeyring.kbx
@end example

Likewise, you can fetch keys to a specific keybox file like this:

@example
gpg --no-default-keyring --keyring mykeyring.kbx \
  --recv-keys @value{OPENPGP-SIGNING-KEY-ID}
@end example

@ref{GPG Configuration Options, @option{--keyring},, gnupg, Using the GNU
Privacy Guard}, for more information on GPG's @option{--keyring} option.

@item --key-download=@var{policy}
Handle missing OpenPGP keys according to @var{policy}, which may be one
of:

@table @code
@item always
Always download missing OpenPGP keys from the key server, and add them
to the user's GnuPG keyring.

@item never
Never try to download missing OpenPGP keys.  Instead just bail out.

@item interactive
When a package signed with an unknown OpenPGP key is encountered, ask
the user whether to download it or not.  This is the default behavior.
@end table

@item --key-server=@var{host}
Use @var{host} as the OpenPGP key server when importing a public key.

@end table

The @code{github} updater uses the
@uref{https://developer.github.com/v3/, GitHub API} to query for new
releases.  When used repeatedly e.g.@: when refreshing all packages,
GitHub will eventually refuse to answer any further API requests.  By
default 60 API requests per hour are allowed, and a full refresh on all
GitHub packages in Guix requires more than this.  Authentication with
GitHub through the use of an API token alleviates these limits.  To use
an API token, set the environment variable @code{GUIX_GITHUB_TOKEN} to a
token procured from @uref{https://github.com/settings/tokens} or
otherwise.


@node Invoking guix lint
@section Invoking @command{guix lint}

@cindex @command{guix lint}
@cindex package, checking for errors
The @command{guix lint} command is meant to help package developers avoid
common errors and use a consistent style.  It runs a number of checks on
a given set of packages in order to find common mistakes in their
definitions.  Available @dfn{checkers} include (see
@code{--list-checkers} for a complete list):

@table @code
@item synopsis
@itemx description
Validate certain typographical and stylistic rules about package
descriptions and synopses.

@item inputs-should-be-native
Identify inputs that should most likely be native inputs.

@item source
@itemx home-page
@itemx mirror-url
@itemx github-url
@itemx source-file-name
Probe @code{home-page} and @code{source} URLs and report those that are
invalid.  Suggest a @code{mirror://} URL when applicable.  If the
@code{source} URL redirects to a GitHub URL, recommend usage of the GitHub
URL.  Check that the source file name is meaningful, e.g.@: is not just a
version number or ``git-checkout'', without a declared @code{file-name}
(@pxref{origin Reference}).

@item cve
@cindex security vulnerabilities
@cindex CVE, Common Vulnerabilities and Exposures
Report known vulnerabilities found in the Common Vulnerabilities and
Exposures (CVE) databases of the current and past year
@uref{https://nvd.nist.gov/download.cfm#CVE_FEED, published by the US
NIST}.

To view information about a particular vulnerability, visit pages such as:

@itemize
@item
@indicateurl{https://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-YYYY-ABCD}
@item
@indicateurl{https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-YYYY-ABCD}
@end itemize

@noindent
where @code{CVE-YYYY-ABCD} is the CVE identifier---e.g.,
@code{CVE-2015-7554}.

Package developers can specify in package recipes the
@uref{https://nvd.nist.gov/cpe.cfm,Common Platform Enumeration (CPE)}
name and version of the package when they differ from the name or version
that Guix uses, as in this example:

@example
(package
  (name "grub")
  ;; @dots{}
  ;; CPE calls this package "grub2".
  (properties '((cpe-name . "grub2")
                (cpe-version . "2.3")))
@end example

@c See <http://www.openwall.com/lists/oss-security/2017/03/15/3>.
Some entries in the CVE database do not specify which version of a
package they apply to, and would thus ``stick around'' forever.  Package
developers who found CVE alerts and verified they can be ignored can
declare them as in this example:

@example
(package
  (name "t1lib")
  ;; @dots{}
  ;; These CVEs no longer apply and can be safely ignored.
  (properties `((lint-hidden-cve . ("CVE-2011-0433"
                                    "CVE-2011-1553"
                                    "CVE-2011-1554"
                                    "CVE-2011-5244")))))
@end example

@item formatting
Warn about obvious source code formatting issues: trailing white space,
use of tabulations, etc.
@end table

The general syntax is:

@example
guix lint @var{options} @var{package}@dots{}
@end example

If no package is given on the command line, then all packages are checked.
The @var{options} may be zero or more of the following:

@table @code
@item --list-checkers
@itemx -l
List and describe all the available checkers that will be run on packages
and exit.

@item --checkers
@itemx -c
Only enable the checkers specified in a comma-separated list using the
names returned by @code{--list-checkers}.

@end table

@node Invoking guix size
@section Invoking @command{guix size}

@cindex size
@cindex package size
@cindex closure
@cindex @command{guix size}
The @command{guix size} command helps package developers profile the
disk usage of packages.  It is easy to overlook the impact of an
additional dependency added to a package, or the impact of using a
single output for a package that could easily be split (@pxref{Packages
with Multiple Outputs}).  Such are the typical issues that
@command{guix size} can highlight.

The command can be passed one or more package specifications
such as @code{gcc@@4.8}
or @code{guile:debug}, or a file name in the store.  Consider this
example:

@example
$ guix size coreutils
store item                               total    self
/gnu/store/@dots{}-gcc-5.5.0-lib           60.4    30.1  38.1%
/gnu/store/@dots{}-glibc-2.27              30.3    28.8  36.6%
/gnu/store/@dots{}-coreutils-8.28          78.9    15.0  19.0%
/gnu/store/@dots{}-gmp-6.1.2               63.1     2.7   3.4%
/gnu/store/@dots{}-bash-static-4.4.12       1.5     1.5   1.9%
/gnu/store/@dots{}-acl-2.2.52              61.1     0.4   0.5%
/gnu/store/@dots{}-attr-2.4.47             60.6     0.2   0.3%
/gnu/store/@dots{}-libcap-2.25             60.5     0.2   0.2%
total: 78.9 MiB
@end example

@cindex closure
The store items listed here constitute the @dfn{transitive closure} of
Coreutils---i.e., Coreutils and all its dependencies, recursively---as
would be returned by:

@example
$ guix gc -R /gnu/store/@dots{}-coreutils-8.23
@end example

Here the output shows three columns next to store items.  The first column,
labeled ``total'', shows the size in mebibytes (MiB) of the closure of
the store item---that is, its own size plus the size of all its
dependencies.  The next column, labeled ``self'', shows the size of the
item itself.  The last column shows the ratio of the size of the item
itself to the space occupied by all the items listed here.

In this example, we see that the closure of Coreutils weighs in at
79@tie{}MiB, most of which is taken by libc and GCC's run-time support
libraries.  (That libc and GCC's libraries represent a large fraction of
the closure is not a problem @i{per se} because they are always available
on the system anyway.)

When the package(s) passed to @command{guix size} are available in the
store@footnote{More precisely, @command{guix size} looks for the
@emph{ungrafted} variant of the given package(s), as returned by
@code{guix build @var{package} --no-grafts}.  @xref{Security Updates},
for information on grafts.}, @command{guix size} queries the daemon to determine its
dependencies, and measures its size in the store, similar to @command{du
-ms --apparent-size} (@pxref{du invocation,,, coreutils, GNU
Coreutils}).

When the given packages are @emph{not} in the store, @command{guix size}
reports information based on the available substitutes
(@pxref{Substitutes}).  This makes it possible it to profile disk usage of
store items that are not even on disk, only available remotely.

You can also specify several package names:

@example
$ guix size coreutils grep sed bash
store item                               total    self
/gnu/store/@dots{}-coreutils-8.24          77.8    13.8  13.4%
/gnu/store/@dots{}-grep-2.22               73.1     0.8   0.8%
/gnu/store/@dots{}-bash-4.3.42             72.3     4.7   4.6%
/gnu/store/@dots{}-readline-6.3            67.6     1.2   1.2%
@dots{}
total: 102.3 MiB
@end example

@noindent
In this example we see that the combination of the four packages takes
102.3@tie{}MiB in total, which is much less than the sum of each closure
since they have a lot of dependencies in common.

The available options are:

@table @option

@item --substitute-urls=@var{urls}
Use substitute information from @var{urls}.
@xref{client-substitute-urls, the same option for @code{guix build}}.

@item --sort=@var{key}
Sort lines according to @var{key}, one of the following options:

@table @code
@item self
the size of each item (the default);
@item closure
the total size of the item's closure.
@end table

@item --map-file=@var{file}
Write a graphical map of disk usage in PNG format to @var{file}.

For the example above, the map looks like this:

@image{images/coreutils-size-map,5in,, map of Coreutils disk usage
produced by @command{guix size}}

This option requires that
@uref{http://wingolog.org/software/guile-charting/, Guile-Charting} be
installed and visible in Guile's module search path.  When that is not
the case, @command{guix size} fails as it tries to load it.

@item --system=@var{system}
@itemx -s @var{system}
Consider packages for @var{system}---e.g., @code{x86_64-linux}.

@end table

@node Invoking guix graph
@section Invoking @command{guix graph}

@cindex DAG
@cindex @command{guix graph}
@cindex package dependencies
Packages and their dependencies form a @dfn{graph}, specifically a
directed acyclic graph (DAG).  It can quickly become difficult to have a
mental model of the package DAG, so the @command{guix graph} command
provides a visual representation of the DAG.  By default,
@command{guix graph} emits a DAG representation in the input format of
@uref{http://www.graphviz.org/, Graphviz}, so its output can be passed
directly to the @command{dot} command of Graphviz.  It can also emit an
HTML page with embedded JavaScript code to display a ``chord diagram''
in a Web browser, using the @uref{https://d3js.org/, d3.js} library, or
emit Cypher queries to construct a graph in a graph database supporting
the @uref{http://www.opencypher.org/, openCypher} query language.
The general syntax is:

@example
guix graph @var{options} @var{package}@dots{}
@end example

For example, the following command generates a PDF file representing the
package DAG for the GNU@tie{}Core Utilities, showing its build-time
dependencies:

@example
guix graph coreutils | dot -Tpdf > dag.pdf
@end example

The output looks like this:

@image{images/coreutils-graph,2in,,Dependency graph of the GNU Coreutils}

Nice little graph, no?

But there is more than one graph!  The one above is concise: it is the
graph of package objects, omitting implicit inputs such as GCC, libc,
grep, etc.  It is often useful to have such a concise graph, but
sometimes one may want to see more details.  @command{guix graph} supports
several types of graphs, allowing you to choose the level of detail:

@table @code
@item package
This is the default type used in the example above.  It shows the DAG of
package objects, excluding implicit dependencies.  It is concise, but
filters out many details.

@item reverse-package
This shows the @emph{reverse} DAG of packages.  For example:

@example
guix graph --type=reverse-package ocaml
@end example

...@: yields the graph of packages that depend on OCaml.

Note that for core packages this can yield huge graphs.  If all you want
is to know the number of packages that depend on a given package, use
@command{guix refresh --list-dependent} (@pxref{Invoking guix refresh,
@option{--list-dependent}}).

@item bag-emerged
This is the package DAG, @emph{including} implicit inputs.

For instance, the following command:

@example
guix graph --type=bag-emerged coreutils | dot -Tpdf > dag.pdf
@end example

...@: yields this bigger graph:

@image{images/coreutils-bag-graph,,5in,Detailed dependency graph of the GNU Coreutils}

At the bottom of the graph, we see all the implicit inputs of
@var{gnu-build-system} (@pxref{Build Systems, @code{gnu-build-system}}).

Now, note that the dependencies of these implicit inputs---that is, the
@dfn{bootstrap dependencies} (@pxref{Bootstrapping})---are not shown
here, for conciseness.

@item bag
Similar to @code{bag-emerged}, but this time including all the bootstrap
dependencies.

@item bag-with-origins
Similar to @code{bag}, but also showing origins and their dependencies.

@item derivation
This is the most detailed representation: It shows the DAG of
derivations (@pxref{Derivations}) and plain store items.  Compared to
the above representation, many additional nodes are visible, including
build scripts, patches, Guile modules, etc.

For this type of graph, it is also possible to pass a @file{.drv} file
name instead of a package name, as in:

@example
guix graph -t derivation `guix system build -d my-config.scm`
@end example

@item module
This is the graph of @dfn{package modules} (@pxref{Package Modules}).
For example, the following command shows the graph for the package
module that defines the @code{guile} package:

@example
guix graph -t module guile | dot -Tpdf > module-graph.pdf
@end example
@end table

All the types above correspond to @emph{build-time dependencies}.  The
following graph type represents the @emph{run-time dependencies}:

@table @code
@item references
This is the graph of @dfn{references} of a package output, as returned
by @command{guix gc --references} (@pxref{Invoking guix gc}).

If the given package output is not available in the store, @command{guix
graph} attempts to obtain dependency information from substitutes.

Here you can also pass a store file name instead of a package name.  For
example, the command below produces the reference graph of your profile