Add command 'nix store path-from-hash-part'

This exposes the Store::queryPathFromHashPart() interface in the CLI.

1 files changed, 20 insertions, 0 deletions

diff --git a/src/nix/path-from-hash-part.md b/src/nix/path-from-hash-part.md
new file mode 100644
index 000000000..788e13ab6
--- /dev/null
+++ b/src/nix/path-from-hash-part.md
@@ -0,0 +1,20 @@
+R""(
+
+# Examples
+
+* Return the full store path with the given hash part:
+
+  ```console
+  # nix store path-from-hash-part --store https://cache.nixos.org/ 0i2jd68mp5g6h2sa5k9c85rb80sn8hi9
+  /nix/store/0i2jd68mp5g6h2sa5k9c85rb80sn8hi9-hello-2.10
+  ```
+
+# Description
+
+Given the hash part of a store path (that is, the 32 characters
+following `/nix/store/`), return the full store path. This is
+primarily useful in the implementation of binary caches, where a
+request for a `.narinfo` file only supplies the hash part
+(e.g. `https://cache.nixos.org/0i2jd68mp5g6h2sa5k9c85rb80sn8hi9.narinfo`).
+
+)""