home-manager: use `shellHook` to install

This changes the installation command from

    nix-shell $HM_PATH -A install --run 'home-manager switch'

to

    nix-shell $HM_PATH -A install

The added shell hook will print some useful information and run
`home-manager switch`.

1 files changed, 37 insertions, 0 deletions

diff --git a/home-manager/install.nix b/home-manager/install.nix
new file mode 100644
index 00000000000..c6d3aa4e4ca
--- /dev/null
+++ b/home-manager/install.nix
@@ -0,0 +1,37 @@
+{ home-manager, pkgs }:
+
+pkgs.runCommand
+  "home-manager-install"
+  {
+    propagatedBuildInputs = [ home-manager ];
+    shellHook = ''
+      echo
+      echo "Creating initial Home Manager generation..."
+      echo
+
+      if home-manager switch; then
+        cat <<EOF
+
+      All done! The home-manager tool should now be installed and you
+      can edit
+
+          ''${XDG_CONFIG_HOME:-~/.config}/nixpkgs/home.nix
+
+      to configure Home Manager. Run 'man home-configuration.nix' to
+      see all available options.
+      EOF
+        exit 0
+      else
+        cat <<EOF
+
+      Uh oh, the installation failed! Please create an issue at
+
+          https://github.com/rycee/home-manager/issues
+
+      if the error seems to be the fault of Home Manager.
+      EOF
+        exit 1
+      fi
+    '';
+  }
+  ""