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


nix nar - create or inspect NAR files


nix nar [option...] subcommand

where subcommand is one of the following:

  • nix nar cat - print the contents of a file inside a NAR file on stdout
  • nix nar dump-path - serialise a path to stdout in NAR format
  • nix nar ls - show information about a path inside a NAR file


nix nar provides several subcommands for creating and inspecting Nix Archives (NARs).

File format

For the definition of the NAR file format, see Figure 5.2 in https://edolstra.github.io/pubs/phd-thesis.pdf.


  • --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    Consider all previously downloaded files out-of-date.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.