6.9 Invoking guix describe

Often you may want to answer questions like: “Which revision of Guix am I using?” or “Which channels am I using?” This is useful information in many situations: if you want to replicate an environment on a different machine or user account, if you want to report a bug or to determine what change in the channels you are using caused it, or if you want to record your system state for reproducibility purposes. The guix describe command answers these questions.

When run from a guix pulled guix, guix describe displays the channel(s) that it was built from, including their repository URL and commit IDs (see Channels):

$ guix describe
Generation 10	Sep 03 2018 17:32:44	(current)
  guix e0fa68c
    repository URL: https://git.savannah.gnu.org/git/guix.git
    branch: master
    commit: e0fa68c7718fffd33d81af415279d6ddb518f727

If you’re familiar with the Git version control system, this is similar in spirit to git describe; the output is also similar to that of guix pull --list-generations, but limited to the current generation (see the --list-generations option). Because the Git commit ID shown above unambiguously refers to a snapshot of Guix, this information is all it takes to describe the revision of Guix you’re using, and also to replicate it.

To make it easier to replicate Guix, guix describe can also be asked to return a list of channels instead of the human-readable description above:

$ guix describe -f channels
(list (channel
        (name 'guix)
        (url "https://git.savannah.gnu.org/git/guix.git")
        (commit
          "e0fa68c7718fffd33d81af415279d6ddb518f727")
        (introduction
          (make-channel-introduction
            "9edb3f66fd807b096b48283debdcddccfea34bad"
            (openpgp-fingerprint
              "BBB0 2DDF 2CEA F6A8 0D1D  E643 A2A0 6DF2 A33A 54FA")))))

You can save this to a file and feed it to guix pull -C on some other machine or at a later point in time, which will instantiate this exact Guix revision (see the -C option). From there on, since you’re able to deploy the same revision of Guix, you can just as well replicate a complete software environment. We humbly think that this is awesome, and we hope you’ll like it too!

The details of the options supported by guix describe are as follows:

--format=format

-f format

Produce output in the specified format, one of:

human

produce human-readable output;

channels

produce a list of channel specifications that can be passed to guix pull -C or installed as ~/.config/guix/channels.scm (see Invoking guix pull);

channels-sans-intro

like channels, but omit the introduction field; use it to produce a channel specification suitable for Guix version 1.1.0 or earlier—the introduction field has to do with channel authentication (see Channel Authentication) and is not supported by these older versions;

json ¶

produce a list of channel specifications in JSON format;

recutils

produce a list of channel specifications in Recutils format.

--list-formats

Display available formats for --format option.

--profile=profile

-p profile

Display information about profile.