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nix3-store-copy-log(1) General Commands Manual nix3-store-copy-log(1)

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


nix store copy-log - copy build logs between Nix stores


nix store copy-log [option…] installables


To copy the build log of the hello package from to the local store:

# nix store copy-log --from --eval-store auto nixpkgs#hello
You can verify that the log is available locally:

# nix log --substituters '' nixpkgs#hello
(The flag --substituters '' avoids querying for the log.)
To copy the log for a specific store derivation via SSH:

# nix store copy-log --to ssh-ng://machine /nix/store/ilgm50plpmcgjhcp33z6n4qbnpqfhxym-glibc-2.33-59.drv


nix store copy-log copies build logs between two Nix stores. The source store is specified using --from and the destination using --to. If one of these is omitted, it defaults to the local store.


  • --from store-uri
    URL of the source Nix store.
  • --to store-uri
    URL of the destination Nix store.

Common evaluation options:

  • --arg name expr
    Pass the value expr as the argument name to Nix functions.
  • --argstr name string
    Pass the string string as the argument name to Nix functions.
  • --eval-store store-url
    The Nix store to use for evaluations.
  • --impure
    Allow access to mutable paths and repositories.
  • --include / -I path
    Add path to the list of locations used to look up <...> file names.
  • --override-flake original-ref resolved-ref
    Override the flake registries, redirecting original-ref to resolved-ref.

Common flake-related options:

  • --commit-lock-file
    Commit changes to the flake’s lock file.
  • --inputs-from flake-url
    Use the inputs of the specified flake as registry entries.
  • --no-registries
    Don’t allow lookups in the flake registries. This option is deprecated; use --no-use-registries.
  • --no-update-lock-file
    Do not allow any updates to the flake’s lock file.
  • --no-write-lock-file
    Do not write the flake’s newly generated lock file.
  • --override-input input-path flake-url
    Override a specific flake input (e.g. dwarffs/nixpkgs). This implies --no-write-lock-file.
  • --recreate-lock-file
    Recreate the flake’s lock file from scratch.
  • --update-input input-path
    Update a specific flake input (ignoring its previous entry in the lock file).

Options that change the interpretation of installables:

  • --derivation
    Operate on the store derivation rather than its outputs.
  • --expr expr
    Interpret installables as attribute paths relative to the Nix expression expr.
  • --file / -f file
    Interpret installables as attribute paths relative to the Nix expression stored in file. If file is the character -, then a Nix expression will be read from standard input.