1 files changed, 51 insertions, 0 deletions
diff --git a/nixos/modules/programs/bash/command-not-found.nix b/nixos/modules/programs/bash/command-not-found.nix
new file mode 100644
index 00000000000..502320446a3
--- /dev/null
+++ b/nixos/modules/programs/bash/command-not-found.nix
@@ -0,0 +1,51 @@
+# This module provides suggestions of packages to install if the user
+# tries to run a missing command in Bash.  This is implemented using a
+# SQLite database that maps program names to Nix package names (e.g.,
+# "pdflatex" is mapped to "tetex").
+
+{ config, pkgs, ... }:
+
+with pkgs.lib;
+
+let
+
+  commandNotFound = pkgs.substituteAll {
+    name = "command-not-found";
+    dir = "bin";
+    src = ./command-not-found.pl;
+    isExecutable = true;
+    inherit (pkgs) perl;
+    perlFlags = concatStrings (map (path: "-I ${path}/lib/perl5/site_perl ")
+      [ pkgs.perlPackages.DBI pkgs.perlPackages.DBDSQLite ]);
+  };
+
+in
+
+{
+
+  programs.bash.interactiveShellInit =
+    ''
+      # This function is called whenever a command is not found.
+      command_not_found_handle() {
+        local p=/run/current-system/sw/bin/command-not-found
+        if [ -x $p -a -f /nix/var/nix/profiles/per-user/root/channels/nixos/programs.sqlite ]; then
+          # Run the helper program.
+          $p "$1"
+          # Retry the command if we just installed it.
+          if [ $? = 126 ]; then
+            "$@"
+          else
+            return 127
+          fi
+        else
+          echo "$1: command not found" >&2
+          return 127
+        fi
+      }
+    '';
+
+  environment.systemPackages = [ commandNotFound ];
+
+  # TODO: tab completion for uninstalled commands! :-)
+
+}