The purpose of
guix environment is to assist hackers in
creating reproducible development environments without polluting their
package profile. The
guix environment tool takes one or more
packages, builds all of their inputs, and creates a shell
environment to use them.
The general syntax is:
guix environment options package…
The following example spawns a new shell set up for the development of GNU Guile:
guix environment guile
If the needed dependencies are not built yet,
automatically builds them. The environment of the new shell is an augmented
version of the environment that
guix environment was run in.
It contains the necessary search paths for building the given package
added to the existing environment variables. To create a “pure”
environment, in which the original environment variables have been unset,
guix environment defines the
variable in the shell it spawns; its value is the file name of the
profile of this environment. This allows users to, say, define a
specific prompt for development environments in their .bashrc
(see Bash Startup Files in The GNU Bash Reference Manual):
if [ -n "$GUIX_ENVIRONMENT" ] then export PS1="\u@\h \w [dev]\$ " fi
... or to browse the profile:
$ ls "$GUIX_ENVIRONMENT/bin"
Additionally, more than one package may be specified, in which case the union of the inputs for the given packages are used. For example, the command below spawns a shell where all of the dependencies of both Guile and Emacs are available:
guix environment guile emacs
Sometimes an interactive shell session is not desired. An arbitrary
command may be invoked by placing the
-- token to separate the
command from the rest of the arguments:
guix environment guile -- make -j4
In other situations, it is more convenient to specify the list of
packages needed in the environment. For example, the following command
python from an environment containing Python 2.7 and
guix environment --ad-hoc python2-numpy python-2.7 -- python
Furthermore, one might want the dependencies of a package and also some
additional packages that are not build-time or runtime dependencies, but
are useful when developing nonetheless. Because of this, the
--ad-hoc flag is positional. Packages appearing before
--ad-hoc are interpreted as packages whose dependencies will be
added to the environment. Packages appearing after are interpreted as
packages that will be added to the environment directly. For example,
the following command creates a Guix development environment that
additionally includes Git and strace:
guix environment guix --ad-hoc git strace
Sometimes it is desirable to isolate the environment as much as possible, for maximal purity and reproducibility. In particular, when using Guix on a host distro that is not GuixSD, it is desirable to prevent access to /usr/bin and other system-wide resources from the development environment. For example, the following command spawns a Guile REPL in a “container” where only the store and the current working directory are mounted:
guix environment --ad-hoc --container guile -- guile
--containeroption requires Linux-libre 3.19 or newer.
The available options are summarized below.
Make file a symlink to the profile for this environment, and register it as a garbage collector root.
This is useful if you want to protect your environment from garbage collection, to make it “persistent”.
When this option is omitted, the environment is protected from garbage
collection only for the duration of the
session. This means that next time you recreate the same environment,
you could have to rebuild or re-download packages. See Invoking guix gc, for more on GC roots.
Create an environment for the package or list of packages that expr evaluates to.
For example, running:
guix environment -e '(@ (gnu packages maths) petsc-openmpi)'
starts a shell with the environment for this specific variant of the PETSc package.
guix environment --ad-hoc -e '(@ (gnu) %base-packages)'
starts a shell with all the GuixSD base packages available.
The above commands only use the default output of the given packages. To select other outputs, two element tuples can be specified:
guix environment --ad-hoc -e '(list ( (gnu packages bash) bash) "include")'
Create an environment for the package or list of packages that the code within file evaluates to.
As an example, file might contain a definition like this (see Defining Packages):
(use-modules (guix) (gnu packages gdb) (gnu packages autotools) (gnu packages texinfo)) ;; Augment the package definition of GDB with the build tools ;; needed when developing GDB (and which are not needed when ;; simply installing it.) (package (inherit gdb) (native-inputs `(("autoconf" ,autoconf-2.64) ("automake" ,automake) ("texinfo" ,texinfo) ,@(package-native-inputs gdb))))
Include all specified packages in the resulting environment, as if an ad hoc package were defined with them as inputs. This option is useful for quickly creating an environment without having to write a package expression to contain the desired inputs.
For instance, the command:
guix environment --ad-hoc guile guile-sdl -- guile
guile in an environment where Guile and Guile-SDL are
Note that this example implicitly asks for the default output of
guile-sdl, but it is possible to ask for a
glib:bin asks for the
glib (see Packages with Multiple Outputs).
This option may be composed with the default behavior of
environment. Packages appearing before
--ad-hoc are interpreted
as packages whose dependencies will be added to the environment, the
default behavior. Packages appearing after are interpreted as packages
that will be added to the environment directly.
Unset existing environment variables when building the new environment. This has the effect of creating an environment in which search paths only contain package inputs.
Display the environment variable definitions that make up the environment.
Attempt to build for system—e.g.,
Run command within an isolated container. The current working directory outside the container is mapped inside the container. Additionally, a dummy home directory is created that matches the current user’s home directory, and /etc/passwd is configured accordingly. The spawned process runs as the current user outside the container, but has root privileges in the context of the container.
For containers, share the network namespace with the host system. Containers created without this flag only have access to the loopback device.
For containers, expose the file system source from the host system as the read-only file system target within the container. If target is not specified, source is used as the target mount point in the container.
The example below spawns a Guile REPL in a container in which the user’s home directory is accessible read-only via the /exchange directory:
guix environment --container --expose=$HOME=/exchange --ad-hoc guile -- guile
For containers, share the file system source from the host system as the writable file system target within the container. If target is not specified, source is used as the target mount point in the container.
The example below spawns a Guile REPL in a container in which the user’s home directory is accessible for both reading and writing via the /exchange directory:
guix environment --container --share=$HOME=/exchange --ad-hoc guile -- guile
also supports all of the common build options that
build supports (see Common Build Options).
Users sometimes wrongfully augment
environment variables such as
PATH in their ~/.bashrc
file. As a consequence, when
guix environment launches it, Bash
may read ~/.bashrc, thereby introducing “impurities” in these
environment variables. It is an error to define such environment
variables in .bashrc; instead, they should be defined in
.bash_profile, which is sourced only by log-in shells.
See Bash Startup Files in The GNU Bash Reference Manual, for
details on Bash start-up files.