This program is experimental and its interface is subject to change.


nix store prefetch-file - download a file into the Nix store


nix store prefetch-file [option...] url


  • Download a file to the Nix store:

    # nix store prefetch-file https://releases.nixos.org/nix/nix-2.3.10/nix-2.3.10.tar.xz
    Downloaded 'https://releases.nixos.org/nix/nix-2.3.10/nix-2.3.10.tar.xz' to
    '/nix/store/vbdbi42hgnc4h7pyqzp6h2yf77kw93aw-source' (hash
  • Download a file and get the SHA-512 hash:

    # nix store prefetch-file --json --hash-type sha512 \
        https://releases.nixos.org/nix/nix-2.3.10/nix-2.3.10.tar.xz \
      | jq -r .hash


This command downloads the file url to the Nix store. It prints out the resulting store path and the cryptographic hash of the contents of the file.

The name component of the store path defaults to the last component of url, but this can be overridden using --name.


  • --executable

    Make the resulting file executable. Note that this causes the resulting hash to be a NAR hash rather than a flat file hash.

  • --expected-hash hash

    The expected hash of the file.

  • --hash-type hash-algo

    Hash algorithm (md5, sha1, sha256, or sha512).

  • --json

    Produce output in JSON format, suitable for consumption by another program.

  • --name name

    Override the name component of the resulting store path. It defaults to the base name of url.

  • --unpack

    Unpack the archive (which must be a tarball or zip file) and add the result to the Nix store.

  • --debug

    Set the logging verbosity level to 'debug'.

  • --log-format format

    Set the format of log output; one of raw, internal-json, bar or bar-with-logs.

  • --print-build-logs / -L

    Print full build logs on standard error.

  • --quiet

    Decrease the logging verbosity level.

  • --verbose / -v

    Increase the logging verbosity level.

Miscellaneous global options

  • --help

    Show usage information.

  • --offline

    Disable substituters and consider all previously downloaded files up-to-date.

  • --option name value

    Set the Nix configuration setting name to value (overriding nix.conf).

  • --refresh

    Consider all previously downloaded files out-of-date.

  • --version

    Show version information.


See man nix.conf for overriding configuration settings with command line flags.