command-not-found: add module

modules/programs/command-not-found/command-not-found.nix

@@ -0,0 +1,57 @@
+# Adapted from Nixpkgs.
+
+{ config, lib, pkgs, ... }:
+
+with lib;
+
+let
+  cfg = config.programs.command-not-found;
+  commandNotFound = pkgs.substituteAll {
+    name = "command-not-found";
+    dir = "bin";
+    src = ./command-not-found.pl;
+    isExecutable = true;
+    inherit (pkgs) perl;
+    inherit (cfg) dbPath;
+    perlFlags = concatStrings (map (path: "-I ${path}/lib/perl5/site_perl ")
+      [ pkgs.perlPackages.DBI pkgs.perlPackages.DBDSQLite pkgs.perlPackages.StringShellQuote ]);
+  };
+
+  shInit = commandNotFoundHandlerName: ''
+    # This function is called whenever a command is not found.
+    ${commandNotFoundHandlerName}() {
+      local p=${commandNotFound}/bin/command-not-found
+      if [ -x $p -a -f ${cfg.dbPath} ]; then
+        # Run the helper program.
+        $p "$@"
+      else
+        echo "$1: command not found" >&2
+        return 127
+      fi
+    }
+  '';
+
+in
+
+{
+  options.programs.command-not-found = {
+    enable = mkEnableOption "command-not-found hook for interactive shell";
+
+    dbPath = mkOption {
+      default = "/nix/var/nix/profiles/per-user/root/channels/nixos/programs.sqlite" ;
+      description = ''
+        Absolute path to <filename>programs.sqlite</filename>. By
+        default this file will be provided by your channel
+        (nixexprs.tar.xz).
+      '';
+      type = types.path;
+    };
+  };
+
+  config = mkIf cfg.enable {
+    programs.bash.initExtra = shInit "command_not_found_handle";
+    programs.zsh.initExtra = shInit "command_not_found_handler";
+
+    home.packages = [ commandNotFound ];
+  };
+}