nix-super/src/nix/log.md

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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.

)""