Merge changes Id1a67156,I03f4c7c1,I146736bb,I3b1453cb into main

* changes:
  docs: clarify how ^ works for -E/-f installables
  docs: give translation examples from nix-build -E/-A to installables
  docs: clarify how the different kinds of installables are selected
  docs: guide to installables docs in installable commands' docs

src/nix/build.md

@@ -1,5 +1,7 @@
 R""(
 
+**Note:** this command's interface is based heavily around [*installables*](./nix.md#installables), which you may want to read about first (`nix --help`).
+
 # Examples
 
 * Build the default package from the flake in the current directory:

src/nix/bundle.md

@@ -1,5 +1,7 @@
 R""(
 
+**Note:** this command's interface is based heavily around [*installables*](./nix.md#installables), which you may want to read about first (`nix --help`).
+
 # Examples
 
 * Bundle Hello:

src/nix/derivation-add.md

@@ -1,5 +1,7 @@
 R""(
 
+**Note:** this command's interface is based heavily around [*installables*](./nix.md#installables), which you may want to read about first (`nix --help`).
+
 # Description
 
 This command reads from standard input a JSON representation of a

src/nix/derivation-show.md

@@ -1,5 +1,7 @@
 R""(
 
+**Note:** this command's interface is based heavily around [*installables*](./nix.md#installables), which you may want to read about first (`nix --help`).
+
 # Examples
 
 * Show the [store derivation] that results from evaluating the Hello

src/nix/develop.md

@@ -1,5 +1,7 @@
 R""(
 
+**Note:** this command's interface is based heavily around [*installables*](./nix.md#installables), which you may want to read about first (`nix --help`).
+
 # Examples
 
 * Start a shell with the build environment of the default package of

src/nix/diff-closures.md

@@ -1,5 +1,7 @@
 R""(
 
+**Note:** this command's interface is based heavily around [*installables*](./nix.md#installables), which you may want to read about first (`nix --help`).
+
 # Examples
 
 * Show what got added and removed between two versions of the NixOS

src/nix/edit.md

@@ -1,5 +1,7 @@
 R""(
 
+**Note:** this command's interface is based heavily around [*installables*](./nix.md#installables), which you may want to read about first (`nix --help`).
+
 # Examples
 
 * Open the Nix expression of the GNU Hello package:

src/nix/eval.md

@@ -1,5 +1,7 @@
 R""(
 
+**Note:** this command's interface is based heavily around [*installables*](./nix.md#installables), which you may want to read about first (`nix --help`).
+
 # Examples
 
 * Evaluate a Nix expression given on the command line:

src/nix/fmt.md

@@ -1,5 +1,7 @@
 R""(
 
+**Note:** this command's interface is based heavily around [*installables*](./nix.md#installables), which you may want to read about first (`nix --help`).
+
 # Examples
 
 With [nixpkgs-fmt](https://github.com/nix-community/nixpkgs-fmt):

src/nix/log.md

@@ -1,5 +1,7 @@
 R""(
 
+**Note:** this command's interface is based heavily around [*installables*](./nix.md#installables), which you may want to read about first (`nix --help`).
+
 # Examples
 
 * Get the build log of GNU Hello:

src/nix/nix.md

@@ -59,9 +59,13 @@ These are command line arguments that represent something that can be realised i
 The following types of installable are supported by most commands:
 
 - [Flake output attribute](#flake-output-attribute) (experimental)
+  - This is the default
 - [Store path](#store-path)
+  - This is assumed if the argument is a Nix store path or a symlink to a Nix store path
 - [Nix file](#nix-file), optionally qualified by an attribute path
+  - Specified with `--file`/`-f`
 - [Nix expression](#nix-expression), optionally qualified by an attribute path
+  - Specified with `--expr`/`-E`
 
 For most commands, if no installable is specified, `.` is assumed.
 That is, Nix will operate on the default flake output attribute of the flake in the current directory.
@@ -158,16 +162,28 @@ When the option `-f` / `--file` *path* \[*attrpath*...\] is given, installables
 If attribute paths are provided, commands will operate on the corresponding values accessible at these paths.
 The Nix expression in that file, or any selected attribute, must evaluate to a derivation.
 
+To emulate the `nix-build '<nixpkgs>' -A hello` pattern, use:
+
+```console
+$ nix build -f '<nixpkgs>' hello
+```
+
 ### Nix expression
 
 Example: `--expr 'import <nixpkgs> {}' hello`
 
-When the option `--expr` *expression* \[*attrpath*...\] is given, installables are interpreted as the value of the of the Nix expression.
+When the option `-E` / `--expr` *expression* \[*attrpath*...\] is given, installables are interpreted as the value of the of the Nix expression.
 If attribute paths are provided, commands will operate on the corresponding values accessible at these paths.
 The Nix expression, or any selected attribute, must evaluate to a derivation.
 
 You may need to specify `--impure` if the expression references impure inputs (such as `<nixpkgs>`).
 
+To emulate the `nix-build -E 'with import <nixpkgs> { }; hello' pattern use:
+
+```console
+$ nix build --impure -E 'with import <nixpkgs> { }; hello'
+```
+
 ## Derivation output selection
 
 Derivations can have multiple outputs, each corresponding to a
@@ -176,9 +192,10 @@ that contains programs, and a `dev` output that provides development
 artifacts like C/C++ header files. The outputs on which `nix` commands
 operate are determined as follows:
 
-* You can explicitly specify the desired outputs using the syntax
-  *installable*`^`*output1*`,`*...*`,`*outputN*. For example, you can
-  obtain the `dev` and `static` outputs of the `glibc` package:
+* You can explicitly specify the desired outputs using the syntax *installable*`^`*output1*`,`*...*`,`*outputN* — that is, a caret followed immediately by a comma-separated list of derivation outputs to select.
+  For installables specified as [Flake output attributes](#flake-output-attribute) or [Store paths](#store-path), the output is specified in the same argument:
+
+  For example, you can obtain the `dev` and `static` outputs of the `glibc` package:
 
   ```console
   # nix build 'nixpkgs#glibc^dev,static'
@@ -193,6 +210,19 @@ operate are determined as follows:
   …
   ```
 
+  For `-e`/`--expr` and `-f`/`--file`, the derivation output is specified as part of the attribute path:
+
+  ```console
+  $ nix build -f '<nixpkgs>' 'glibc^dev,static'
+  $ nix build --impure -E 'import <nixpkgs> { }' 'glibc^dev,static'
+  ```
+
+  This syntax is the same even if the actual attribute path is empty:
+
+  ```console
+  $ nix build -E 'let pkgs = import <nixpkgs> { }; in pkgs.glibc' '^dev,static'
+  ```
+
 * You can also specify that *all* outputs should be used using the
   syntax *installable*`^*`. For example, the following shows the size
   of all outputs of the `glibc` package in the binary cache:

src/nix/path-info.md

@@ -1,5 +1,7 @@
 R""(
 
+**Note:** this command's interface is based heavily around [*installables*](./nix.md#installables), which you may want to read about first (`nix --help`).
+
 # Examples
 
 * Print the store path produced by `nixpkgs#hello`:

src/nix/print-dev-env.md

@@ -1,5 +1,7 @@
 R""(
 
+**Note:** this command's interface is based heavily around [*installables*](./nix.md#installables), which you may want to read about first (`nix --help`).
+
 # Examples
 
 * Apply the build environment of GNU hello to the current shell:

src/nix/profile-install.md

@@ -1,5 +1,7 @@
 R""(
 
+**Note:** this command's interface is based heavily around [*installables*](./nix.md#installables), which you may want to read about first (`nix --help`).
+
 # Examples
 
 * Install a package from Nixpkgs:

src/nix/profile-remove.md

@@ -1,5 +1,7 @@
 R""(
 
+**Note**: unlike [`nix profile install`](./nix3-profile-install.md), this command does *not* take installables.
+
 # Examples
 
 * Remove a package by name:

src/nix/profile-upgrade.md

@@ -1,5 +1,7 @@
 R""(
 
+**Note**: unlike [`nix profile install`](./nix3-profile-install.md), this command does *not* take installables.
+
 # Examples
 
 * Upgrade all packages that were installed using an unlocked flake

src/nix/repl.md

@@ -1,5 +1,7 @@
 R""(
 
+**Note:** this command's interface is based heavily around [*installables*](./nix.md#installables), which you may want to read about first (`nix --help`).
+
 # Examples
 
 * Display all special commands within the REPL:

src/nix/run.md

@@ -1,5 +1,7 @@
 R""(
 
+**Note:** this command's interface is based heavily around [*installables*](./nix.md#installables), which you may want to read about first (`nix --help`).
+
 # Examples
 
 * Run the default app from the `blender-bin` flake:

src/nix/search.md

@@ -1,5 +1,7 @@
 R""(
 
+**Note:** this command's interface is based heavily around [*installables*](./nix.md#installables), which you may want to read about first (`nix --help`).
+
 # Examples
 
 * Show all packages in the `nixpkgs` flake:

src/nix/shell.md

@@ -1,5 +1,7 @@
 R""(
 
+**Note:** this command's interface is based heavily around [*installables*](./nix.md#installables), which you may want to read about first (`nix --help`).
+
 # Examples
 
 * Start a shell providing `youtube-dl` from the `nixpkgs` flake:

src/nix/why-depends.md

@@ -1,5 +1,7 @@
 R""(
 
+**Note:** this command's interface is based heavily around [*installables*](./nix.md#installables), which you may want to read about first (`nix --help`).
+
 # Examples
 
 * Show one path through the dependency graph leading from Hello to