initial commit

source/recipes/devshell/flake/flake.nix

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+{
+  inputs = {
+    nixpkgs.url = "github:NixOS/nixpkgs";
+    flake-utils.url = "github:numtide/flake-utils";
+    hello-flake.url = "git+https://codeberg.org/mhwombat/hello-flake";
+  };
+
+  outputs = { self, nixpkgs, flake-utils, hello-flake }:
+    flake-utils.lib.eachDefaultSystem (system:
+      let
+        pkgs = import nixpkgs { inherit system; };
+      in
+      {
+        devShells = rec {
+          default = pkgs.mkShell {
+            buildInputs = [ hello-flake.packages.${system}.hello ];
+          };
+        };
+      }
+    );
+}

source/recipes/devshell/nixpkg/main.adoc0

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+= A top level package from the Nixpkgs/NixOS repo
+
+////
+$ mkdir tempwork
+$ cd tempwork
+$ cp ../flake.nix flake.nix
+$ git add flake.nix
+$ nix develop
+$ git add flake.lock
+$ git commit -a -m temp
+////
+
+[source,nix,linenums,highlight=15]
+.flake.nix
+....
+$# cat flake.nix
+....
+
+Here's a demonstration using the shell.
+
+....
+$ cowsay "Moo!"
+$# ../../../../../start-shell nix develop <<EOL
+$ cowsay "Moo!"
+$# EOL
+....
+
+////
+Good adoc0 scripts clean up after themselves.
+$ cd .. ; rm -rf tempwork # clean up
+////

source/recipes/nix-shell/main.adoc0

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+= An (old-style) Nix shell with access to a flake
+
+If you are maintaining legacy code,
+you may need to provide access to a flake in a `nix-shell`.
+Here's how.
+
+[source,nix,linenums]
+.shell.nix
+....
+include::shell.nix[]
+....
+
+Here's a demonstration using the shell.
+
+....
+$# echo '$ nix-shell'
+$# nix-shell --run bash <<EOL
+$ hello-flake
+$# EOL
+....

source/recipes/run/main.adoc0

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+= Running programs directly (without installing them)
+
+== A top level package from the Nixpkgs/NixOS repo
+
+....
+$ nix run nixpkgs#cowsay "Moo!"
+....
+
+[#flakeref]
+== Flakes
+
+=== A flake defined in a local file
+
+....
+$ nix run ~/codeberg/hello-flake
+....
+
+=== A flake defined in a remote git repo
+
+....
+$ nix run git+https://codeberg.org/mhwombat/hello-flake
+....
+
+To run a specific branch, use the command below.
+
+....
+nix run git+https://codeberg.org/mhwombat/hello-flake?ref=main
+....
+
+To run a specific branch and revision, use the command below.
+
+....
+nix run git+https://codeberg.org/mhwombat/hello-flake?ref=main&rev=d44728bce88a6f9d1d37dbf4720ece455e997606
+....
+
+=== A flake defined in a zip archive
+
+....
+$ nix run https://codeberg.org/mhwombat/hello-flake/archive/main.zip
+....
+
+=== A flake defined in a compressed tar archive
+
+....
+$ nix run https://codeberg.org/mhwombat/hello-flake/archive/main.tar.gz
+....
+
+=== Other types of flake references
+
+See https://nix.dev/manual/nix/stable/command-ref/new-cli/nix3-flake#flake-reference-attributes.