Add 'nix path-info' manpage

src/nix/path-info.cc

@@ -29,38 +29,15 @@ struct CmdPathInfo : StorePathsCommand, MixJSON
         return "query information about store paths";
     }
 
-    Category category() override { return catSecondary; }
+    std::string doc() override
-
-    Examples examples() override
     {
-        return {
+        return
-            Example{
+          #include "path-info.md"
-                "To show the closure sizes of every path in the current NixOS system closure, sorted by size:",
+          ;
-                "nix path-info -rS /run/current-system | sort -nk2"
-            },
-            Example{
-                "To show a package's closure size and all its dependencies with human readable sizes:",
-                "nix path-info -rsSh nixpkgs#rust"
-            },
-            Example{
-                "To check the existence of a path in a binary cache:",
-                "nix path-info -r /nix/store/7qvk5c91...-geeqie-1.1 --store https://cache.nixos.org/"
-            },
-            Example{
-                "To print the 10 most recently added paths (using --json and the jq(1) command):",
-                "nix path-info --json --all | jq -r 'sort_by(.registrationTime)[-11:-1][].path'"
-            },
-            Example{
-                "To show the size of the entire Nix store:",
-                "nix path-info --json --all | jq 'map(.narSize) | add'"
-            },
-            Example{
-                "To show every path whose closure is bigger than 1 GB, sorted by closure size:",
-                "nix path-info --json --all -S | jq 'map(select(.closureSize > 1e9)) | sort_by(.closureSize) | map([.path, .closureSize])'"
-            },
-        };
     }
 
+    Category category() override { return catSecondary; }
+
     void printSize(uint64_t value)
     {
         if (!humanReadable) {

src/nix/path-info.md

@@ -0,0 +1,94 @@
+R""(
+
+# Examples
+
+* Print the store path produced by `nixpkgs#hello`:
+
+  ```console
+  # nix path-info nixpkgs#hello
+  /nix/store/v5sv61sszx301i0x6xysaqzla09nksnd-hello-2.10
+  ```
+
+* Show the closure sizes of every path in the current NixOS system
+  closure, sorted by size:
+
+  ```console
+  # nix path-info -rS /run/current-system | sort -nk2
+  /nix/store/hl5xwp9kdrd1zkm0idm3kkby9q66z404-empty                                                96
+  /nix/store/27324qvqhnxj3rncazmxc4mwy79kz8ha-nameservers                                         112
+  …
+  /nix/store/539jkw9a8dyry7clcv60gk6na816j7y8-etc                                          5783255504
+  /nix/store/zqamz3cz4dbzfihki2mk7a63mbkxz9xq-nixos-system-machine-20.09.20201112.3090c65  5887562256
+  ```
+
+* Show a package's closure size and all its dependencies with human
+  readable sizes:
+
+  ```console
+  # nix path-info -rsSh nixpkgs#rustc
+  /nix/store/01rrgsg5zk3cds0xgdsq40zpk6g51dz9-ncurses-6.2-dev      386.7K   69.1M
+  /nix/store/0q783wnvixpqz6dxjp16nw296avgczam-libpfm-4.11.0          5.9M   37.4M
+  …
+  ```
+
+* Check the existence of a path in a binary cache:
+
+  ```console
+  # nix path-info -r /nix/store/blzxgyvrk32ki6xga10phr4sby2xf25q-geeqie-1.5.1 --store https://cache.nixos.org/
+  path '/nix/store/blzxgyvrk32ki6xga10phr4sby2xf25q-geeqie-1.5.1' is not valid
+
+  ```
+
+* Print the 10 most recently added paths (using --json and the jq(1)
+  command):
+
+  ```console
+  # nix path-info --json --all | jq -r 'sort_by(.registrationTime)[-11:-1][].path'
+  ```
+
+* Show the size of the entire Nix store:
+
+  ```console
+  # nix path-info --json --all | jq 'map(.narSize) | add'
+  49812020936
+  ```
+
+* Show every path whose closure is bigger than 1 GB, sorted by closure
+  size:
+
+  ```console
+  # nix path-info --json --all -S \
+    | jq 'map(select(.closureSize > 1e9)) | sort_by(.closureSize) | map([.path, .closureSize])'
+  [
+    …,
+    [
+      "/nix/store/zqamz3cz4dbzfihki2mk7a63mbkxz9xq-nixos-system-machine-20.09.20201112.3090c65",
+      5887562256
+    ]
+  ]
+  ```
+
+* Print the path of the store derivation produced by `nixpkgs#hello`:
+
+  ```console
+  # nix path-info --derivation nixpkgs#hello
+  /nix/store/s6rn4jz1sin56rf4qj5b5v8jxjm32hlk-hello-2.10.drv
+ ```
+
+# Description
+
+This command shows information about the store paths produced by
+*installables*, or about all paths in the store if you pass `--all`.
+
+By default, this command only prints the store paths. You can get
+additional information by passing flags such as `--closure-size`,
+--size`, `--sigs` or `--json`.
+
+> **Warning**
+>
+> Note that `nix path-info` does not build or substitute the
+> *installables* you specify. Thus, if the corresponding store paths
+> don't already exist, this command will fail. You can use `nix build`
+> to ensure that they exist.
+
+)""