nix3-copy - Man Page

copy paths between Nix stores

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

Examples

Copy Firefox from the local store to a binary cache in /tmp/cache:

# nix copy --to file:///tmp/cache $(type -p firefox)

Note the file:// - without this, the destination is a chroot store, not a binary cache.

Copy all store paths from a local binary cache in /tmp/cache to the local store:

# nix copy --all --from file:///tmp/cache

Copy the entire current NixOS system closure to another machine via SSH:

# nix copy --substitute-on-destination --to ssh://server /run/current-system

The -s flag causes the remote machine to try to substitute missing store paths, which may be faster if the link between the local and remote machines is slower than the link between the remote machine and its substituters (e.g. https://cache.nixos.org).

Copy a closure from another machine via SSH:

# nix copy --from ssh://server /nix/store/a6cnl93nk1wxnq84brbbwr6hxw9gp2w9-blender-2.79-rc2

Copy Hello to a binary cache in an Amazon S3 bucket:

# nix copy --to s3://my-bucket?region=eu-west-1 nixpkgs#hello

or to an S3-compatible storage system:

# nix copy --to s3://my-bucket?region=eu-west-1&endpoint=example.com nixpkgs#hello

Note that this only works if Nix is built with AWS support.

Copy a closure from /nix/store to the chroot store /tmp/nix/nix/store:

# nix copy --to /tmp/nix nixpkgs#hello --no-check-sigs

Update the NixOS system profile to point to a closure copied from a remote machine:

# nix copy --from ssh://server \
  --profile /nix/var/nix/profiles/system \
  /nix/store/r14v3km89zm3prwsa521fab5kgzvfbw4-nixos-system-foobar-24.05.20240925.759537f

Description

nix copy copies store path closures 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.

Options

--from store-uri
URL of the source Nix store.
--no-check-sigs
Do not require that paths are signed by trusted keys.
--out-link / -o path
Create symlinks prefixed with path to the top-level store paths fetched from the source store.
--profile path
The profile to operate on.
--stdin
Read installables from the standard input. No default installable applied.
--substitute-on-destination / -s
Whether to try substitutes on the destination store (only supported by SSH stores).
--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.
--arg-from-file name path
Pass the contents of file path as the argument name to Nix functions.
--arg-from-stdin name
Pass the contents of stdin as the argument name to Nix functions.
--argstr name string
Pass the string string as the argument name to Nix functions.
--debugger
Start an interactive environment if evaluation fails.
--eval-store store-url
The URL of the Nix store to use for evaluation, i.e. to store derivations (.drv files) and inputs referenced by them.
--impure
Allow access to mutable paths and repositories.
--include / -I path
Add path to search path entries used to resolve lookup paths
This option may be given multiple times.
Paths added through -I take precedence over the nix-path configuration setting and the NIX_PATH environment variable .
--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.
DEPRECATED
Use --no-use-registries instead.
--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.
--output-lock-file flake-lock-path
Write the given lock file instead of flake.lock within the top-level flake.
--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.
DEPRECATED
Use nix flake update instead.
--reference-lock-file flake-lock-path
Read the given lock file instead of flake.lock within the top-level flake.
--update-input input-path
Update a specific flake input (ignoring its previous entry in the lock file).
DEPRECATED
Use nix flake update instead.

Logging-related options

--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.
--repair
During evaluation, rewrite missing or corrupted files in the Nix store. During building, rebuild missing or corrupted store paths.
--version
Show version information.

Options that change the interpretation of installables

--all
Apply the operation to every store path.
--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 is read from standard input. Implies --impure.
--no-recursive
Apply operation to specified paths only.
Note
See man nix.conf for overriding configuration settings with command line flags.

Synopsis