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Diffstat (limited to 'doc/manual/src/command-ref/nix-store/dump.md')
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diff --git a/doc/manual/src/command-ref/nix-store/dump.md b/doc/manual/src/command-ref/nix-store/dump.md new file mode 100644 index 000000000..62656d599 --- /dev/null +++ b/doc/manual/src/command-ref/nix-store/dump.md @@ -0,0 +1,40 @@ +# Name + +`nix-store --dump` - write a single path to a Nix Archive + +## Synopsis + +`nix-store` `--dump` *path* + +## Description + +The operation `--dump` produces a NAR (Nix ARchive) file containing the +contents of the file system tree rooted at *path*. The archive is +written to standard output. + +A NAR archive is like a TAR or Zip archive, but it contains only the +information that Nix considers important. For instance, timestamps are +elided because all files in the Nix store have their timestamp set to 0 +anyway. Likewise, all permissions are left out except for the execute +bit, because all files in the Nix store have 444 or 555 permission. + +Also, a NAR archive is *canonical*, meaning that “equal” paths always +produce the same NAR archive. For instance, directory entries are +always sorted so that the actual on-disk order doesn’t influence the +result. This means that the cryptographic hash of a NAR dump of a +path is usable as a fingerprint of the contents of the path. Indeed, +the hashes of store paths stored in Nix’s database (see `nix-store -q +--hash`) are SHA-256 hashes of the NAR dump of each store path. + +NAR archives support filenames of unlimited length and 64-bit file +sizes. They can contain regular files, directories, and symbolic links, +but not other types of files (such as device nodes). + +A Nix archive can be unpacked using `nix-store +--restore`. + +{{#include ./opt-common.md}} + +{{#include ../opt-common.md}} + +{{#include ../env-common.md}} |