6.6 Invoking guix pull

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 guix pull: the command downloads the latest Guix source code and package descriptions, and deploys it. Source code is downloaded from a Git repository, by default the official GNU Guix repository, though this can be customized. guix pull ensures that the code it downloads is authentic by verifying that commits are signed by Guix developers.

Specifically, guix pull downloads code from the channels (see 通道) specified by one of the followings, in this order:

1. the --channels option;
2. the user’s ~/.config/guix/channels.scm file;
3. the system-wide /etc/guix/channels.scm file;
4. the built-in default channels specified in the %default-channels variable.

On completion, 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 version. New guix sub-commands added by the update also become available.

Any user can update their Guix copy using guix pull, and the effect is limited to the user who ran guix pull. For instance, when user root runs guix pull, this has no effect on the version of Guix that user alice sees, and vice versa.

The result of running guix pull is a profile available under ~/.config/guix/current containing the latest Guix. Thus, make sure to add it to the beginning of your search path so that you use the latest version, and similarly for the Info manual (see 文档):

export PATH="$HOME/.config/guix/current/bin:$PATH"
export INFOPATH="$HOME/.config/guix/current/share/info:$INFOPATH"

The --list-generations or -l option lists past generations produced by guix pull, along with details about their provenance:

$ guix pull -l
Generation 1	Jun 10 2018 00:18:18
  guix 65956ad
    repository URL: https://git.savannah.gnu.org/git/guix.git
    branch: origin/master
    commit: 65956ad3526ba09e1f7a40722c96c6ef7c0936fe

Generation 2	Jun 11 2018 11:02:49
  guix e0cc7f6
    repository URL: https://git.savannah.gnu.org/git/guix.git
    branch: origin/master
    commit: e0cc7f669bec22c37481dd03a7941c7d11a64f1d

Generation 3	Jun 13 2018 23:31:07	(current)
  guix 844cc1c
    repository URL: https://git.savannah.gnu.org/git/guix.git
    branch: origin/master
    commit: 844cc1c8f394f03b404c5bb3aee086922373490c

See guix describe, for other ways to describe the current status of Guix.

This ~/.config/guix/current profile works exactly like the profiles created by guix package (see Invoking guix package). That is, you can list generations, roll back to the previous generation—i.e., the previous Guix—and so on:

$ guix pull --roll-back
switched from generation 3 to 2
$ guix pull --delete-generations=1
deleting /var/guix/profiles/per-user/charlie/current-guix-1-link

You can also use guix package (see Invoking guix package) to manage the profile by naming it explicitly:

$ guix package -p ~/.config/guix/current --roll-back
switched from generation 3 to 2
$ guix package -p ~/.config/guix/current --delete-generations=1
deleting /var/guix/profiles/per-user/charlie/current-guix-1-link

The guix pull command is usually invoked with no arguments, but it supports the following options:

--url=url

--commit=commit

--branch=branch

Download code for the guix channel from the specified url, at the given commit (a valid Git commit ID represented as a hexadecimal string or the name of a tag), or branch.

These options are provided for convenience, but you can also specify your configuration in the ~/.config/guix/channels.scm file or using the --channels option (see below).

--channels=file

-C file

Read the list of channels from file instead of ~/.config/guix/channels.scm or /etc/guix/channels.scm. file must contain Scheme code that evaluates to a list of channel objects. See 通道, for more information.

--news

-N

Display news written by channel authors for their users for changes made since the previous generation (see Writing Channel News). When --details is passed, additionally display new and upgraded packages.

You can view that information for previous generations with guix pull -l.

--list-generations[=pattern]

-l [pattern]

List all the generations of ~/.config/guix/current or, if pattern is provided, the subset of generations that match pattern. The syntax of pattern is the same as with guix package --list-generations (see Invoking guix package).

By default, this prints information about the channels used in each revision as well as the corresponding news entries. If you pass --details, it will also print the list of packages added and upgraded in each generation compared to the previous one.

--details

Instruct --list-generations or --news to display more information about the differences between subsequent generations—see above.

--roll-back ¶

Roll back to the previous generation of ~/.config/guix/current—i.e., undo the last transaction.

--switch-generation=pattern ¶

-S pattern

Switch to a particular generation defined by pattern.

pattern may be either a generation number or a number prefixed with “+” or “-”. The latter means: move forward/backward by a specified number of generations. For example, if you want to return to the latest generation after --roll-back, use --switch-generation=+1.

--delete-generations[=pattern]

-d [pattern]

When pattern is omitted, delete all generations except the current one.

This command accepts the same patterns as --list-generations. When pattern is specified, delete the matching generations. When pattern specifies a duration, generations older than the specified duration match. For instance, --delete-generations=1m deletes generations that are more than one month old.

If the current generation matches, it is not deleted.

Note that deleting generations prevents rolling back to them. Consequently, this command must be used with care.

See Invoking guix describe, for a way to display information about the current generation only.

--profile=profile

-p profile

Use profile instead of ~/.config/guix/current.

--dry-run

-n

Show which channel commit(s) would be used and what would be built or substituted but do not actually do it.

--allow-downgrades

Allow pulling older or unrelated revisions of channels than those currently in use.

By default, guix pull protects against so-called “downgrade attacks” whereby the Git repository of a channel would be reset to an earlier or unrelated revision of itself, potentially leading you to install older, known-vulnerable versions of software packages.

注: Make sure you understand its security implications before using --allow-downgrades.

--disable-authentication

Allow pulling channel code without authenticating it.

By default, guix pull authenticates code downloaded from channels by verifying that its commits are signed by authorized developers, and raises an error if this is not the case. This option instructs it to not perform any such verification.

注: Make sure you understand its security implications before using --disable-authentication.

--system=system

-s system

Attempt to build for system—e.g., i686-linux—instead of the system type of the build host.

--bootstrap

Use the bootstrap Guile to build the latest Guix. This option is only useful to Guix developers.

The channel mechanism allows you to instruct guix pull which repository and branch to pull from, as well as additional repositories containing package modules that should be deployed. See 通道, for more information.

In addition, guix pull supports all the common build options (see 普通的构建选项).