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

Name

nix log - show the build log of the specified packages or paths, if available

Synopsis

nix log [option...] installable

Examples

Get the build log of GNU Hello:
```
# nix log nixpkgs#hello
```

Get the build log of a specific store path:

# nix log /nix/store/lmngj4wcm9rkv3w4dfhzhcyij3195hiq-thunderbird-52.2.1

Get a build log from a specific binary cache:

# nix log --store https://cache.nixos.org nixpkgs#hello

Description

This command prints the log of a previous build of the derivation installable on standard output.

Nix looks for build logs in two places:

In the directory /nix/var/log/nix/drvs, which contains logs for locally built derivations.
In the binary caches listed in the substituters setting. Logs should be named <cache>/log/<base-name-of-store-path>, where store-path is a derivation, e.g. https://cache.nixos.org/log/dvmig8jgrdapvbyxb1rprckdmdqx08kv-hello-2.10.drv. For non-derivation store paths, Nix will first try to determine the deriver by fetching the .narinfo file for this store path.

Options

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.
--debugger

Start an interactive environment if evaluation fails.
--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).

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.
--version

Show version information.

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. Implies --impure.

Options to override configuration settings:

--accept-flake-config

Enable the accept-flake-config setting.
--access-tokens value

Set the access-tokens setting.
--allow-dirty

Enable the allow-dirty setting.
--allow-import-from-derivation

Enable the allow-import-from-derivation setting.
--allow-new-privileges

Enable the allow-new-privileges setting.
--allow-symlinked-store

Enable the allow-symlinked-store setting.
--allow-unsafe-native-code-during-evaluation

Enable the allow-unsafe-native-code-during-evaluation setting.
--allowed-impure-host-deps value

Set the allowed-impure-host-deps setting.
--allowed-uris value

Set the allowed-uris setting.
--allowed-users value

Set the allowed-users setting.
--auto-allocate-uids

Enable the auto-allocate-uids setting.
--auto-optimise-store

Enable the auto-optimise-store setting.
--bash-prompt value

Set the bash-prompt setting.
--bash-prompt-prefix value

Set the bash-prompt-prefix setting.
--bash-prompt-suffix value

Set the bash-prompt-suffix setting.
--build-hook value

Set the build-hook setting.
--build-poll-interval value

Set the build-poll-interval setting.
--build-users-group value

Set the build-users-group setting.
--builders value

Set the builders setting.
--builders-use-substitutes

Enable the builders-use-substitutes setting.
--commit-lockfile-summary value

Set the commit-lockfile-summary setting.
--compress-build-log

Enable the compress-build-log setting.
--connect-timeout value

Set the connect-timeout setting.
--cores value

Set the cores setting.
--diff-hook value

Set the diff-hook setting.
--download-attempts value

Set the download-attempts setting.
--download-speed value

Set the download-speed setting.
--enforce-determinism

Enable the enforce-determinism setting.
--eval-cache

Enable the eval-cache setting.
--experimental-features value

Set the experimental-features setting.
--extra-access-tokens value

Append to the access-tokens setting.
--extra-allowed-impure-host-deps value

Append to the allowed-impure-host-deps setting.
--extra-allowed-uris value

Append to the allowed-uris setting.
--extra-allowed-users value

Append to the allowed-users setting.
--extra-experimental-features value

Append to the experimental-features setting.
--extra-extra-platforms value

Append to the extra-platforms setting.
--extra-hashed-mirrors value

Append to the hashed-mirrors setting.
--extra-ignored-acls value

Append to the ignored-acls setting.
--extra-nix-path value

Append to the nix-path setting.
--extra-platforms value

Set the extra-platforms setting.
--extra-plugin-files value

Append to the plugin-files setting.
--extra-sandbox-paths value

Append to the sandbox-paths setting.
--extra-secret-key-files value

Append to the secret-key-files setting.
--extra-substituters value

Append to the substituters setting.
--extra-system-features value

Append to the system-features setting.
--extra-trusted-public-keys value

Append to the trusted-public-keys setting.
--extra-trusted-substituters value

Append to the trusted-substituters setting.
--extra-trusted-users value

Append to the trusted-users setting.
--fallback

Enable the fallback setting.
--filter-syscalls

Enable the filter-syscalls setting.
--flake-registry value

Set the flake-registry setting.
--fsync-metadata

Enable the fsync-metadata setting.
--gc-reserved-space value

Set the gc-reserved-space setting.
--hashed-mirrors value

Set the hashed-mirrors setting.
--http-connections value

Set the http-connections setting.
--http2

Enable the http2 setting.
--id-count value

Set the id-count setting.
--ignore-try

Enable the ignore-try setting.
--ignored-acls value

Set the ignored-acls setting.
--impersonate-linux-26

Enable the impersonate-linux-26 setting.
--keep-build-log

Enable the keep-build-log setting.
--keep-derivations

Enable the keep-derivations setting.
--keep-env-derivations

Enable the keep-env-derivations setting.
--keep-failed

Enable the keep-failed setting.
--keep-going

Enable the keep-going setting.
--keep-outputs

Enable the keep-outputs setting.
--log-lines value

Set the log-lines setting.
--max-build-log-size value

Set the max-build-log-size setting.
--max-free value

Set the max-free setting.
--max-jobs value

Set the max-jobs setting.
--max-silent-time value

Set the max-silent-time setting.
--min-free value

Set the min-free setting.
--min-free-check-interval value

Set the min-free-check-interval setting.
--nar-buffer-size value

Set the nar-buffer-size setting.
--narinfo-cache-negative-ttl value

Set the narinfo-cache-negative-ttl setting.
--narinfo-cache-positive-ttl value

Set the narinfo-cache-positive-ttl setting.
--netrc-file value

Set the netrc-file setting.
--nix-path value

Set the nix-path setting.
--no-accept-flake-config

Disable the accept-flake-config setting.
--no-allow-dirty

Disable the allow-dirty setting.
--no-allow-import-from-derivation

Disable the allow-import-from-derivation setting.
--no-allow-new-privileges

Disable the allow-new-privileges setting.
--no-allow-symlinked-store

Disable the allow-symlinked-store setting.
--no-allow-unsafe-native-code-during-evaluation

Disable the allow-unsafe-native-code-during-evaluation setting.
--no-auto-allocate-uids

Disable the auto-allocate-uids setting.
--no-auto-optimise-store

Disable the auto-optimise-store setting.
--no-builders-use-substitutes

Disable the builders-use-substitutes setting.
--no-compress-build-log

Disable the compress-build-log setting.
--no-enforce-determinism

Disable the enforce-determinism setting.
--no-eval-cache

Disable the eval-cache setting.
--no-fallback

Disable the fallback setting.
--no-filter-syscalls

Disable the filter-syscalls setting.
--no-fsync-metadata

Disable the fsync-metadata setting.
--no-http2

Disable the http2 setting.
--no-ignore-try

Disable the ignore-try setting.
--no-impersonate-linux-26

Disable the impersonate-linux-26 setting.
--no-keep-build-log

Disable the keep-build-log setting.
--no-keep-derivations

Disable the keep-derivations setting.
--no-keep-env-derivations

Disable the keep-env-derivations setting.
--no-keep-failed

Disable the keep-failed setting.
--no-keep-going

Disable the keep-going setting.
--no-keep-outputs

Disable the keep-outputs setting.
--no-preallocate-contents

Disable the preallocate-contents setting.
--no-print-missing

Disable the print-missing setting.
--no-pure-eval

Disable the pure-eval setting.
--no-require-sigs

Disable the require-sigs setting.
--no-restrict-eval

Disable the restrict-eval setting.
--no-run-diff-hook

Disable the run-diff-hook setting.
--no-sandbox

Disable sandboxing.
--no-sandbox-fallback

Disable the sandbox-fallback setting.
--no-show-trace

Disable the show-trace setting.
--no-substitute

Disable the substitute setting.
--no-sync-before-registering

Disable the sync-before-registering setting.
--no-trace-function-calls

Disable the trace-function-calls setting.
--no-trace-verbose

Disable the trace-verbose setting.
--no-use-case-hack

Disable the use-case-hack setting.
--no-use-cgroups

Disable the use-cgroups setting.
--no-use-registries

Disable the use-registries setting.
--no-use-sqlite-wal

Disable the use-sqlite-wal setting.
--no-warn-dirty

Disable the warn-dirty setting.
--plugin-files value

Set the plugin-files setting.
--post-build-hook value

Set the post-build-hook setting.
--pre-build-hook value

Set the pre-build-hook setting.
--preallocate-contents

Enable the preallocate-contents setting.
--print-missing

Enable the print-missing setting.
--pure-eval

Enable the pure-eval setting.
--relaxed-sandbox

Enable sandboxing, but allow builds to disable it.
--repeat value

Set the repeat setting.
--require-sigs

Enable the require-sigs setting.
--restrict-eval

Enable the restrict-eval setting.
--run-diff-hook

Enable the run-diff-hook setting.
--sandbox

Enable sandboxing.
--sandbox-build-dir value

Set the sandbox-build-dir setting.
--sandbox-dev-shm-size value

Set the sandbox-dev-shm-size setting.
--sandbox-fallback

Enable the sandbox-fallback setting.
--sandbox-paths value

Set the sandbox-paths setting.
--secret-key-files value

Set the secret-key-files setting.
--show-trace

Enable the show-trace setting.
--stalled-download-timeout value

Set the stalled-download-timeout setting.
--start-id value

Set the start-id setting.
--store value

Set the store setting.
--substitute

Enable the substitute setting.
--substituters value

Set the substituters setting.
--sync-before-registering

Enable the sync-before-registering setting.
--system value

Set the system setting.
--system-features value

Set the system-features setting.
--tarball-ttl value

Set the tarball-ttl setting.
--timeout value

Set the timeout setting.
--trace-function-calls

Enable the trace-function-calls setting.
--trace-verbose

Enable the trace-verbose setting.
--trusted-public-keys value

Set the trusted-public-keys setting.
--trusted-substituters value

Set the trusted-substituters setting.
--trusted-users value

Set the trusted-users setting.
--use-case-hack

Enable the use-case-hack setting.
--use-cgroups

Enable the use-cgroups setting.
--use-registries

Enable the use-registries setting.
--use-sqlite-wal

Enable the use-sqlite-wal setting.
--user-agent-suffix value

Set the user-agent-suffix setting.
--warn-dirty

Enable the warn-dirty setting.