9.4 Invoking guix hash

The guix hash command computes the 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

When file is - (a hyphen), guix hash computes the hash of data read from standard input. guix hash has the following options:

--hash=algorithm

-H algorithm

Compute a hash using the specified algorithm, sha256 by default.

algorithm must the name of a cryptographic hash algorithm supported by Libgcrypt via Guile-Gcrypt—e.g., sha512 or sha3-256 (see Hash Functions in Guile-Gcrypt Reference Manual).

--format=fmt

-f fmt

Write the hash in the format specified by fmt.

Supported formats: base64, nix-base32, base32, base16 (hex and hexadecimal can be used as well).

If the --format option is not specified, guix hash will output the hash in nix-base32. This representation is used in the definitions of packages.

--recursive

-r

Compute the hash on file recursively.

In this case, the hash is computed on an archive containing file, including its children if it is a directory. Some of the metadata of file is part of the archive; for instance, when file is a regular file, the hash is different depending on whether file is executable or not. Metadata such as time stamps has no impact on the hash (see Invoking guix archive).

--exclude-vcs

-x

When combined with --recursive, exclude version control system directories (.bzr, .git, .hg, etc.).

As an example, here is how you would compute the hash of a Git checkout, which is useful when using the git-fetch method (see origin Reference):

$ git clone http://example.org/foo.git
$ cd foo
$ guix hash -rx .