This document describes GNU Guix version 0.2, a functional package management tool written for the GNU system.
Copyright © 2012, 2013 Ludovic Courtès
Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.3 or any later version published by the Free Software Foundation; with no Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts. A copy of the license is included in the section entitled “GNU Free Documentation License.”
|• Introduction:||What is Guix about?|
|• Installation:||Installing Guix.|
|• Package Management:||Package installation, upgrade, etc.|
|• Programming Interface:||Using Guix in Scheme.|
|• Utilities:||Package management commands.|
|• GNU Distribution:||Software for your friendly GNU system.|
|• GNU Free Documentation License:||The license of this manual.|
|• Concept Index:||Concepts.|
|• Function Index:||Functions.|
GNU Guix1 is a functional package management tool for the GNU system. Package management consists in all the activities that relate to building packages from source, honoring the build-time and run-time dependencies on packages, installing packages in user environments, upgrading installed packages to new versions or rolling back to a previous set, removing unused software packages, etc.
The term functional refers to a specific package management discipline. In Guix, the package build and installation process is seen as a function, in the mathematical sense: that function takes inputs, such as build scripts, a compiler, and libraries depended on, and returns the installed package. As a pure function, its result depends solely on its inputs—for instance, it cannot refer to software or scripts that were not explicitly passed as inputs. A build function always produces the same result when passed a given set of inputs. Last but not least, a build function cannot alter the system’s environment in any way; for instance, it cannot create, modify, or delete files outside of its build and installation directories. This is achieved by running build processes in dedicated “chroots”, where only their explicit inputs are visible.
The result of package build functions is cached in the file system, in a special directory called the store (see The Store). Each package is installed in a directory of its own, in the store—by default under /nix/store. The directory name contains a hash of all the inputs used to build that package; thus, changing an input yields a different directory name.
This approach is the foundation of Guix’s salient features: support for transactional package upgrades and rollback, per-user installation, and garbage collection of packages (see Features).
Guix has a command-line interface allowing users to build, install, upgrade, and remove packages, as well as a Scheme programming interface. The remainder of this manual describes them.
Last but not least, Guix is used to build a distribution of the GNU system, with many GNU and non-GNU free software packages. See GNU Distribution.
GNU Guix is available for download from its website at http://www.gnu.org/software/guix/. This section describes the software requirements of Guix, as well as how to install it and get ready to use it.
The build procedure for Guix is the same as for other GNU software, and is not covered here. Please see the files README and INSTALL in the Guix source tree for additional details.
|• Requirements:||Software needed to build and run Guix.|
|• Setting Up the Daemon:||Preparing the build daemon’s environment.|
|• Invoking guix-daemon:||Running the build daemon.|
GNU Guix depends on the following packages:
--disable-daemon was passed to
following packages are also needed:
When a working installation of the Nix package manager is available, you
can instead configure Guix with
--disable-daemon. In that case,
Nix replaces the three dependencies above.
Guix is compatible with Nix, so it is possible to share the same store
between both. To do so, you must pass
configure not only the
--with-store-dir value, but also the same
--localstatedir value (the latter is essential because it
specifies where the database that store meta-data about the store is
located, among other things.) The default values are
--disable-daemon is orthogonal and is not required if
your goal is to share the same store as Nix.
Operations such as building a package or running the garbage collector
are all performed by a specialized process, the Guix daemon, on
behalf of clients. Only the daemon may access the store and its
associated database. Thus, any operation that manipulates the store
goes through the daemon. For instance, command-line tools such as
guix package and
guix build communicate with the
daemon (via remote procedure calls) to instruct it what to do.
In a standard multi-user setup, Guix and its daemon—the
guix-daemon program—are installed by the system
administrator; /nix/store is owned by
guix-daemon runs as
root. Unprivileged users may use
Guix tools to build packages or otherwise access the store, and the
daemon will do it on their behalf, ensuring that the store is kept in a
consistent state, and allowing built packages to be shared among users.
guix-daemon runs as
root, you may not want package
build processes themselves to run as
root too, for obvious
security reasons. To avoid that, a special pool of build users
should be created for use by build processes started by the daemon.
These build users need not have a shell and a home directory: they will
just be used when the daemon drops
root privileges in build
processes. Having several such users allows the daemon to launch
distinct build processes under separate UIDs, which guarantees that they
do not interfere with each other—an essential feature since builds are
regarded as pure functions (see Introduction).
On a GNU/Linux system, a build user pool may be created like this (using
Bash syntax and the
# groupadd guix-builder # for i in `seq 1 10`; do useradd -g guix-builder -G guix-builder \ -d /var/empty -s `which nologin` \ -c "Guix build user $i" guix-builder$i; done
guix-daemon program may then be run as
# guix-daemon --build-users-group=guix-builder
Guix may also be used in a single-user setup, with
running as an unprivileged user. However, to maximize non-interference
of build processes, the daemon still needs to perform certain operations
that are restricted to
root on GNU/Linux: it should be able to
run build processes in a chroot, and to run them under different UIDs.
To that end, the
nix-setuid-helper program is provided; it is
a small C program (less than 300 lines) that, if it is made setuid
root, can be executed by the daemon to perform these operations
on its behalf. The
root-owned /etc/nix-setuid.conf file
is read by
nix-setuid-helper; it should contain exactly two
words: the user name under which the authorized
runs, and the name of the build users group.
If you are installing Guix as an unprivileged user and do not have the
ability to make nix-setuid-helper setuid-
root, it is still
possible to run
guix-daemon. However, build processes will
not be isolated from one another, and not from the rest of the system.
Thus, build processes may interfere with each other, and may access
programs, libraries, and other files available on the system—making it
much harder to view them as pure functions.
guix-daemon program implements all the functionality to
access the store. This includes launching build processes, running the
garbage collector, querying the availability of a build result, etc. It
is normally run as
root like this:
# guix-daemon --build-users-group=guix-builder
For details on how to set it up, Setting Up the Daemon.
guix-daemon launches build processes under
different UIDs, taken from the build group specified with
--build-users-group. In addition, each build process is run in a
chroot environment that only contains the subset of the store that the
build process depends on, as specified by its derivation
(see derivation), plus a set of specific
system directories. By default, the latter contains /dev and
The following command-line options are supported:
Take users from group to run build processes (see build users).
Do not use substitutes for build products. That is, always build things locally instead of allowing downloads of pre-built binaries.
Cache build failures. By default, only successful builds are cached.
Use n CPU cores to build each derivation;
0 means as many
The default value is
1, but it may be overridden by clients, such
--cores option of
guix build (see Invoking guix build).
The effect is to define the
NIX_BUILD_CORES environment variable
in the build process, which can then use it to exploit internal
parallelism—for instance, by running
Allow at most n build jobs in parallel. The default value is
Produce debugging output.
This is useful to debug daemon start-up issues, but then it may be
overridden by clients, for example the
--verbosity option of
guix build (see Invoking guix build).
Add dir to the build chroot.
Doing this may change the result of build processes—for instance if they use optional dependencies found in dir when it is available, and not otherwise. For that reason, it is not recommended to do so. Instead, make sure that each derivation declares all the inputs that it needs.
Disable chroot builds.
Using this option is not recommended since, again, it would allow build processes to gain access to undeclared dependencies.
Disable compression of the build logs.
--lose-logs is used, all the build logs are kept in the
localstatedir. To save space, the daemon automatically compresses
them with bzip2 by default. This option disables that.
Disable automatic file “deduplication” in the store.
By default, files added to the store are automatically “deduplicated”: if a newly added file is identical as another one found in the store, the daemon makes the new file a hard link to the other file. This slightly increases the input/output load at the end of a build process. This option disables this.
On Linux-based systems, impersonate Linux 2.6. This means that the
uname system call will report 2.6 as the release number.
This might be helpful to build programs that (usually wrongfully) depend on the kernel version number.
Do not keep build logs. By default they are kept under
Assume system as the current system type. By default it is the
architecture/kernel pair found at configure time, such as
Listen for connections on socket, the file name of a Unix-domain socket. The default socket is localstatedir/daemon-socket/socket. This option is only useful in exceptional circumstances, such as if you need to run several daemons on the same machine.
The purpose of GNU Guix is to allow users to easily install, upgrade, and remove software packages, without having to know about their build procedure or dependencies. Guix also goes beyond this obvious set of features.
This chapter describes the main features of Guix, as well as the package management tools it provides.
|• Features:||How Guix will make your life brighter.|
|• Invoking guix package:||Package installation, removal, etc.|
|• Invoking guix gc:||Running the garbage collector.|
|• Invoking guix pull:||Fetching the latest Guix and distribution.|
When using Guix, each package ends up in the package store, in its
own directory—something that resembles
xxx is a base32 string.
Instead of referring to these directories, users have their own
profile, which points to the packages that they actually want to
use. These profiles are stored within each user’s home directory, at
alice installs GCC 4.7.2. As a result,
/home/alice/.guix-profile/bin/gcc points to
/nix/store/…-gcc-4.7.2/bin/gcc. Now, on the same machine,
bob had already installed GCC 4.8.0. The profile of
simply continues to point to
/nix/store/…-gcc-4.8.0/bin/gcc—i.e., both versions of GCC
coexist on the same system without any interference.
guix package command is the central tool to manage
packages (see Invoking guix package). It operates on those per-user
profiles, and can be used with normal user privileges.
The command provides the obvious install, remove, and upgrade
operations. Each invocation is actually a transaction: either
the specified operation succeeds, or nothing happens. Thus, if the
guix package process is terminated during the transaction,
or if a power outage occurs during the transaction, then the user’s
profile remains in its previous state, and remains usable.
In addition, any package transaction may be rolled back. So, if, for example, an upgrade installs a new version of a package that turns out to have a serious bug, users may roll back to the previous instance of their profile, which was known to work well.
All those packages in the package store may be garbage-collected. Guix can determine which packages are still referenced by the user profiles, and remove those that are provably no longer referenced (see Invoking guix gc). Users may also explicitly remove old generations of their profile so that the packages they refer to can be collected.
Finally, Guix takes a purely functional approach to package management, as described in the introduction (see Introduction). Each /nix/store package directory name contains a hash of all the inputs that were used to build that package—compiler, libraries, build scripts, etc. This direct correspondence allows users to make sure a given package installation matches the current state of their distribution, and helps maximize reproducibility.
This foundation allows Guix to support transparent binary/source deployment. When a pre-built binary for a /nix/store path is available from an external source, Guix just downloads it; otherwise, it builds the package from source, locally.
guix package command is the tool that allows users to
install, upgrade, and remove packages, as well as rolling back to
previous configurations. It operates only on the user’s own profile,
and works with normal user privileges (see Features). Its syntax
guix package options
Primarily, options specifies the operations to be performed during the transaction. Upon completion, a new profile is created, but previous generations of the profile remain available, should the user want to roll back.
For each user, a symlink to the user’s default profile is automatically
created in $HOME/.guix-profile. This symlink always points to the
current generation of the user’s default profile. Thus, users can add
$HOME/.guix-profile/bin to their
variable, and so on.
In a multi-user setup, user profiles must be stored in a place
registered as a garbage-collector root, which
$HOME/.guix-profile points to (see Invoking guix gc). That
directory is normally
localstatedir is the value passed to
--localstatedir, and user is the user name. It must be
root, with user as the owner. When it does not
guix package emits an error about it.
The options can be among the following:
package may specify either a simple package name, such as
guile, or a package name followed by a hyphen and version number,
guile-1.8.8. If no version number is specified, the
newest available version will be selected. In addition, package
may contain a colon, followed by the name of one of the outputs of the
package, as in
Sometimes packages have propagated inputs: these are dependencies that automatically get installed along with the required package.
An example is the GNU MPC library: its C header files refer to those of the GNU MPFR library, which in turn refer to those of the GMP library. Thus, when installing MPC, the MPFR and GMP libraries also get installed in the profile; removing MPC also removes MPFR and GMP—unless they had also been explicitly installed independently.
Besides, packages sometime rely on the definition of environment
variables for their search paths (see explanation of
--search-paths below.) Any missing or possibly incorrect
environment variable definitions are reported here.
Finally, when installing a GNU package, the tool reports the availability of a newer upstream version. In the future, it may provide the option of installing directly from the upstream version, even if that version is not yet in the distribution.
Install the package exp evaluates to.
exp must be a Scheme expression that evaluates to a
<package> object. This option is notably useful to disambiguate
between same-named variants of a package, with expressions such as
(@ (gnu packages base) guile-final).
Note that this option installs the first output of the specified package, which may be insufficient when needing a specific output of a multiple-output package.
Upgrade all the installed packages. When regexp is specified, upgrade only installed packages whose name matches regexp.
Note that this upgrades package to the latest version of packages found
in the distribution currently installed. To update your distribution,
you should regularly run
guix pull (see Invoking guix pull).
Roll back to the previous generation of the profile—i.e., undo the last transaction.
When combined with options such as
--install, roll back occurs
before any other actions.
When rolling back from the first generation that actually contains installed packages, the profile is made to point to the empty profile, also known as profile zero—i.e., it contains no files apart from its own meta-data.
Installing, removing, or upgrading packages from a generation that has been rolled back to overwrites previous future generations. Thus, the history of a profile’s generations is always linear.
Report environment variable definitions, in Bash syntax, that may be needed in order to use the set of installed packages. These environment variables are used to specify search paths for files used by some of the installed packages.
For example, GCC needs the
environment variables to be defined so it can look for headers and
libraries in the user’s profile (see Environment Variables in Using the GNU Compiler Collection (GCC)). If GCC and, say, the C
library are installed in the profile, then
suggest setting these variables to
Use profile instead of the user’s default profile.
Show what would be done without actually doing it.
Build instead of resorting to pre-built substitutes.
Produce verbose output. In particular, emit the environment’s build log on the standard error port.
Use the bootstrap Guile to build the profile. This option is only useful to distribution developers.
In addition to these actions
guix package supports the
following options to query the current state of a profile, or the
availability of packages:
List the available packages whose synopsis or description matches
regexp. Print all the meta-data of matching packages in
recutils format (see GNU recutils databases in GNU recutils manual).
This allows specific fields to be extracted using the
command, for instance:
$ guix package -s malloc | recsel -p name,version name: glibc version: 2.17 name: libgc version: 7.2alpha6
List currently installed packages in the specified profile. When regexp is specified, list only installed packages whose name matches regexp.
For each installed package, print the following items, separated by
tabs: the package name, its version string, the part of the package that
is installed (for instance,
out for the default output,
include for its headers, etc.), and the path of this package in
List packages currently available in the software distribution (see GNU Distribution). When regexp is specified, list only installed packages whose name matches regexp.
For each package, print the following items separated by tabs: its name,
its version string, the parts of the package (
out for the main
lib for libraries and possibly headers, etc.), and the
source location of its definition.
Packages that are installed but not used may be garbage-collected.
guix gc command allows users to explicitly run the garbage
collector to reclaim space from the /nix/store directory.
The garbage collector has a set of known roots: any file under
/nix/store reachable from a root is considered live and
cannot be deleted; any other file is considered dead and may be
deleted. The set of garbage collector roots includes default user
profiles, and may be augmented with
guix build --root, for
example (see Invoking guix build).
guix gc command has three modes of operation: it can be
used to garbage-collect any dead files (the default), to delete specific
--delete option), or to print garbage-collector
information. The available options are listed below:
Collect garbage—i.e., unreachable /nix/store files and sub-directories. This is the default operation when no option is specified.
When min is given, stop once min bytes have been collected.
min may be a number of bytes, or it may include a unit as a
suffix, such as
MiB for mebibytes and
GB for gigabytes.
When min is omitted, collect all the garbage.
Attempt to delete all the store files and directories specified as arguments. This fails if some of the files are not in the store, or if they are still live.
Show the list of dead files and directories still present in the store—i.e., files and directories no longer reachable from any root.
Show the list of live store files and directories.
In addition, the references among existing store files can be queried:
List the references (respectively, the referrers) of store files given as arguments.
Packages are installed or upgraded to the latest version available in
the distribution currently available on your local machine. To update
that distribution, along with the Guix tools, you must run
pull: the command downloads the latest Guix source code and package
descriptions, and deploys it.
guix package will use packages and package
versions from this just-retrieved copy of Guix. Not only that, but all
the Guix commands and Scheme modules will also be taken from that latest
guix sub-commands added by the update also
guix pull command is usually invoked with no arguments,
but it supports the following options:
Produce verbose output, writing build logs to the standard error output.
Use the bootstrap Guile to build the latest Guix. This option is only useful to Guix developers.
GNU Guix provides several Scheme programming interfaces (APIs) to define, build, and query packages. The first interface allows users to write high-level package definitions. These definitions refer to familiar packaging concepts, such as the name and version of a package, its build system, and its dependencies. These definitions can then be turned into concrete build actions.
Build actions are performed by the Guix daemon, on behalf of users. In a standard setup, the daemon has write access to the store—the /nix/store directory—whereas users do not. The recommended setup also has the daemon perform builds in chroots, under a specific build users, to minimize interference with the rest of the system.
Lower-level APIs are available to interact with the daemon and the store. To instruct the daemon to perform a build action, users actually provide it with a derivation. A derivation is a low-level representation of the build actions to be taken, and the environment in which they should occur—derivations are to package definitions what assembly is to C programs.
This chapter describes all these APIs in turn, starting from high-level package definitions.
|• Defining Packages:||Defining new packages.|
|• The Store:||Manipulating the package store.|
|• Derivations:||Low-level interface to package derivations.|
The high-level interface to package definitions is implemented in the
(guix packages) and
(guix build-system) modules. As an
example, the package definition, or recipe, for the GNU Hello
package looks like this:
(use-modules (guix packages) (guix download) (guix build-system gnu) (guix licenses)) (define hello (package (name "hello") (version "2.8") (source (origin (method url-fetch) (uri (string-append "mirror://gnu/hello/hello-" version ".tar.gz")) (sha256 (base32 "0wqd8sjmxfskrflaxywc7gqw7sfawrfvdxd9skxawzfgyy0pzdz6")))) (build-system gnu-build-system) (inputs `(("gawk" ,gawk))) (synopsis "GNU Hello") (description "Yeah...") (home-page "http://www.gnu.org/software/hello/") (license gpl3+)))
Without being a Scheme expert, the reader may have guessed the meaning
of the various fields here. This expression binds variable hello
<package> object, which is essentially a record
(see Scheme records in GNU Guile Reference Manual).
This package object can be inspected using procedures found in the
(guix packages) module; for instance,
There are a few points worth noting in the above package definition:
sourcefield of the package is an
<origin>object. Here, the
(guix download)is used, meaning that the source is a file to be downloaded over FTP or HTTP.
mirror://gnu prefix instructs
url-fetch to use one of
the GNU mirrors defined in
sha256 field specifies the expected SHA256 hash of the file
being downloaded. It is mandatory, and allows Guix to check the
integrity of the file. The
(base32 …) form introduces the
base32 representation of the hash. You can obtain this information with
guix download (see Invoking guix download) and
hash (see Invoking guix hash).
build-systemfield is set to gnu-build-system. The gnu-build-system variable is defined in the
(guix build-system gnu)module, and is bound to a
Naturally, gnu-build-system represents the familiar GNU Build
System, and variants thereof (see configuration and
makefile conventions in GNU Coding Standards). In a
nutshell, packages using the GNU Build System may be configured, built,
and installed with the usual
./configure && make && make check &&
make install command sequence. This is what gnu-build-system
In addition, gnu-build-system ensures that the “standard” environment for GNU packages is available. This includes tools such as GCC, Coreutils, Bash, Make, Diffutils, and Patch.
inputsfield specifies inputs to the build process—i.e., build-time or run-time dependencies of the package. Here, we define an input called
"gawk"whose value is that of the gawk variable; gawk is itself bound to a
Note that GCC, Coreutils, Bash, and other essential tools do not need to be specified as inputs here. Instead, gnu-build-system takes care of ensuring that they are present.
However, any other dependencies need to be specified in the
inputs field. Any dependency not specified here will simply be
unavailable to the build process, possibly leading to a build failure.
There are other fields that package definitions may provide. Of
particular interest is the
arguments field. When specified, it
must be bound to a list of additional arguments to be passed to the
build system. For instance, the above definition could be augmented
with the following field initializer:
(arguments `(#:tests? #f #:configure-flags '("--enable-silent-rules")))
These are keyword arguments (see keyword
arguments in Guile in GNU Guile Reference Manual). They are
passed to gnu-build-system, which interprets them as meaning “do
make check”, and “run configure with the
--enable-silent-rules flag”. The value of these keyword
parameters is actually evaluated in the build stratum—i.e., by a
Guile process launched by the daemon (see Derivations).
Once a package definition is in place2, the
package may actually be built using the
guix build command-line
tool (see Invoking guix build). Eventually, updating the package
definition to a new upstream version can be partly automated by the
guix refresh command (see Invoking guix refresh).
Behind the scenes, a derivation corresponding to the
object is first computed by the
That derivation is stored in a
.drv file under /nix/store.
The build actions it prescribes may then be realized by using the
build-derivations procedure (see The Store).
Return the derivation path and corresponding
of package for system (see Derivations).
package must be a valid
<package> object, and system
must be a string denoting the target system type—e.g.,
"x86_64-linux" for an x86_64 Linux-based GNU system. store
must be a connection to the daemon, which operates on the store
(see The Store).
Conceptually, the store is where derivations that have been successfully built are stored—by default, under /nix/store. Sub-directories in the store are referred to as store paths. The store has an associated database that contains information such has the store paths referred to by each store path, and the list of valid store paths—paths that result from a successful build.
The store is always accessed by the daemon on behalf of its clients (see Invoking guix-daemon). To manipulate the store, clients connect to the daemon over a Unix-domain socket, send it requests, and read the result—these are remote procedure calls, or RPCs.
(guix store) module provides procedures to connect to the
daemon, and to perform RPCs. These are described below.
Connect to the daemon over the Unix-domain socket at file. When reserve-space? is true, instruct it to reserve a little bit of extra space on the file system so that the garbage collector can still operate, should the disk become full. Return a server object.
file defaults to %default-socket-path, which is the normal
location given the options that were passed to
Close the connection to server.
This variable is bound to a SRFI-39 parameter, which refers to the port where build and error logs sent by the daemon should be written.
Procedures that make RPCs all take a server object as their first argument.
#t when path is a valid store path.
Add text under file name in the store, and return its store path. references is the list of store paths referred to by the resulting store path.
Build derivations (a list of derivation paths), and return when
the worker is done building them. Return
#t on success.
This section is currently incomplete.
Low-level build actions and the environment in which they are performed are represented by derivations. A derivation contain the following pieces of information:
Derivations allow clients of the daemon to communicate build actions to
the store. They exist in two forms: as an in-memory representation,
both on the client- and daemon-side, and as files in the store whose
name end in
.drv—these files are referred to as derivation
paths. Derivations paths can be passed to the
procedure to perform the build actions they prescribe (see The Store).
(guix derivations) module provides a representation of
derivations as Scheme objects, along with procedures to create and
otherwise manipulate derivations. The lowest-level primitive to create
a derivation is the
Build a derivation with the given arguments. Return the resulting store
When hash, hash-algo, and hash-mode are given, a fixed-output derivation is created—i.e., one whose result is known in advance, such as a file download.
Here’s an example with a shell script as its builder, assuming store is an open connection to the daemon, and bash points to a Bash executable in the store:
(use-modules (guix utils) (guix store) (guix derivations)) (call-with-values (lambda () (let ((builder ; add the Bash script to the store (add-text-to-store store "my-builder.sh" "echo hello world > $out\n" '()))) (derivation store "foo" (%current-system) bash `("-e" ,builder) '(("HOME" . "/homeless")) '()))) list) ⇒ ("/nix/store/…-foo.drv" #<<derivation> …>)
As can be guessed, this primitive is cumbersome to use directly. An
improved variant is
build-expression->derivation, which allows
the caller to directly pass a Guile expression as the build script:
Return a derivation that executes Scheme expression exp as a
builder for derivation name. inputs must be a list of
(name drv-path sub-drv) tuples; when sub-drv is omitted,
"out" is assumed. modules is a list of names of Guile
modules from the current search path to be copied in the store,
compiled, and made available in the load path during the execution of
((guix build utils) (guix build
exp is evaluated in an environment where
%outputs is bound
to a list of output/path pairs, and where
%build-inputs is bound
to a list of string/output-path pairs made from inputs.
Optionally, env-vars is a list of string pairs specifying the name
and value of environment variables visible to the builder. The builder
terminates by passing the result of exp to
exit; thus, when
#f, the build is considered to have failed.
exp is built using guile-for-build (a derivation). When
guile-for-build is omitted or is
#f, the value of the
%guile-for-build fluid is used instead.
Here’s an example of a single-output derivation that creates a directory containing one file:
(let ((builder '(let ((out (assoc-ref %outputs "out"))) (mkdir out) ; create /nix/store/…-goo (call-with-output-file (string-append out "/test") (lambda (p) (display '(hello guix) p)))))) (build-expression->derivation store "goo" (%current-system) builder '())) ⇒ "/nix/store/…-goo.drv" ⇒ #<<derivation> …>
Remember that the build expression passed to
build-expression->derivation is run by a separate Guile process
than the one that calls
build-expression->derivation: it is run
by a Guile process launched by the daemon, typically in a chroot. So,
while there is a single language for both the host and the build
side, there are really two strata of code: the host-side, and the
This distinction is important to keep in mind, notably when using
higher-level constructs such as gnu-build-system (see Defining Packages). For this reason, Guix modules that are meant to be used in
the build stratum are kept in the
(guix build …) name
This section describes tools primarily targeted at developers and users who write new package definitions. They complement the Scheme programming interface of Guix in a convenient way.
|• Invoking guix build:||Building packages from the command line.|
|• Invoking guix download:||Downloading a file and printing its hash.|
|• Invoking guix hash:||Computing the cryptographic hash of a file.|
|• Invoking guix refresh:||Updating package definitions.|
guix build command builds packages or derivations and
their dependencies, and prints the resulting store paths. Note that it
does not modify the user’s profile—this is the job of the
guix package command (see Invoking guix package). Thus,
it is mainly useful for distribution developers.
The general syntax is:
guix build options package-or-derivation…
package-or-derivation may be either the name of a package found in
the software distribution such as
coreutils-8.20, or a derivation such as
/nix/store/…-coreutils-8.19.drv. Alternatively, the
--expression option may be used to specify a Scheme expression
that evaluates to a package; this is useful when disambiguation among
several same-named packages or package variants is needed.
The options may be zero or more of the following:
Build the package expr evaluates to.
For example, expr may be
(@ (gnu packages guile)
guile-1.8), which unambiguously designates this specific variant of
version 1.8 of Guile.
Build the packages’ source derivations, rather than the packages themselves.
guix build -S gcc returns something like
/nix/store/…-gcc-4.7.2.tar.bz2, which is GCC’s source tarball.
Attempt to build for system—e.g.,
the host’s system type.
An example use of this is on Linux-based systems, which can emulate
different personalities. For instance, passing
--system=i686-linux on an
x86_64-linux system allows users
to build packages in a complete 32-bit environment.
Return the derivation paths, not the output paths, of the given packages.
Keep the build tree of failed builds. Thus, if a build fail, its build tree is kept under /tmp, in a directory whose name is shown at the end of the build log. This is useful when debugging build issues.
Do not build the derivations.
Build instead of resorting to pre-built substitutes.
Allow the use of up to n CPU cores for the build. The special
0 means to use as many CPU cores as available.
Make file a symlink to the result, and register it as a garbage collector root.
Use the given verbosity level. level must be an integer between 0 and 5; higher means more verbose output. Setting a level of 4 or more may be helpful when debugging setup issues with the build daemon.
Behind the scenes,
guix build is essentially an interface to
package-derivation procedure of the
module, and to the
build-derivations procedure of the
When writing a package definition, developers typically need to download
the package’s source tarball, compute its SHA256 hash, and write that
hash in the package definition (see Defining Packages). The
guix download tool helps with this task: it downloads a file
from the given URI, adds it to the store, and prints both its file name
in the store and its SHA256 hash.
The fact that the downloaded file is added to the store saves bandwidth:
when the developer eventually tries to build the newly defined package
guix build, the source tarball will not have to be
downloaded again because it is already in the store. It is also a
convenient way to temporarily stash files, which may be deleted
eventually (see Invoking guix gc).
guix download command supports the same URIs as used in
package definitions. In particular, it supports
https URIs (HTTP over TLS) are supported provided the
Guile bindings for GnuTLS are available in the user’s environment; when
they are not available, an error is raised.
The following option is available:
Write the hash in the format specified by fmt. For more information on the valid values for fmt, Invoking guix hash.
guix hash command computes the SHA256 hash of a file.
It is primarily a convenience tool for anyone contributing to the
distribution: it computes the cryptographic hash of a file, which can be
used in the definition of a package (see Defining Packages).
The general syntax is:
guix hash option file
guix hash has the following option:
Write the hash in the format specified by fmt.
hexadecimal can be used as well).
If the --format option is not specified,
will output the hash in
nix-base32. This representation is used
in the definitions of packages.
The primary audience of the
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:
$ 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
It does so by browsing each package’s FTP directory and determining the highest version number of the source tarballs therein4.
--update, it modifies distribution source files to
update the version numbers and source tarball hashes of those packages’
recipes (see 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
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 it’s successful, the key is added to the user’s keyring; otherwise,
guix refresh reports an error.
The following options are supported:
Update distribution source files (package recipes) in place. Defining Packages, for more information on package definitions.
Select all the packages in subset, one of
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.
non-core subset refers to the remaining packages. It is
typically useful in cases where an update of the core packages would be
guix refresh can be passed one or more package
names, as in this example:
guix refresh -u emacs idutils
The command above specifically updates the
idutils packages. The
--select option would have no
effect in this case.
The following options can be used to customize GnuPG operation:
Use host as the OpenPGP key server when importing a public key.
Use command as the GnuPG 2.x command. command is searched
Guix comes with a distribution of free software5 that form the basis of the GNU system. This
includes core GNU packages such as GNU libc, GCC, and Binutils, as well
as many GNU and non-GNU applications. The complete list of available
packages can be seen by running
guix package (see Invoking guix package):
guix package --list-available
The package definitions of the distribution may are provided by Guile
modules in the
(gnu packages ...) name space—for instance, the
(gnu packages emacs) module exports a variable named
emacs, which is bound to a
(see Defining Packages). The
(gnu packages) module provides
facilities for searching for packages.
The distribution is fully bootstrapped and self-contained:
each package is built based solely on other packages in the
distribution. The root of this dependency graph is a small set of
bootstrap binaries, provided by the
bootstrap) module. These are statically-linked binaries of the core
tools without which building anything at all would be impossible.
Our goal is to build a practical 100% free software distribution of Linux-based and other variants of GNU, with a focus on the promotion and tight integration of GNU components, and an emphasis on programs and tools that help users exert that freedom.
Building this distribution is a cooperative effort, and you are invited to join! Please get in touch with us on email@example.com. We welcome ideas, bug reports, patches, and anything that may be helpful to the project.
Guix is based on the Nix package manager, which was designed and implemented by Eelco Dolstra. Nix pioneered functional package management, and promoted unprecedented features, such as transactional package upgrades and rollbacks, per-user profiles, and referentially transparent build processes. Without this work, Guix would not exist.
The Nix-based software distributions, Nixpkgs and NixOS, have also been an inspiration for Guix.
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|Jump to:||B D F G P S|
|build users:||Setting Up the Daemon|
|daemon:||Setting Up the Daemon|
|functional package management:||Introduction|
|garbage collector:||Invoking guix gc|
|GNU Build System:||Defining Packages|
|propagated inputs:||Invoking guix package|
|search paths:||Invoking guix package|
|store paths:||The Store|
|strata of code:||Derivations|
|Jump to:||B D F G P S|
|Jump to:||A B C D O P V|
|Jump to:||A B C D O P V|
“Guix” is pronounced like “geeks”, or “ɡiːks” using the international phonetic alphabet (IPA).
definitions like the one above may be automatically converted from the
Nixpkgs distribution using the
guix import command.
The term stratum in this context was coined by Manuel Serrano et al. in the context of their work on Hop.
Currently, this only works for GNU packages.
The term “free” here refers to the freedom provided to users of that software.