nixos/vte: init

This module correctly includes the vte.sh script
required for vte terminals like gnome-terminal to show the
CWD in the window title and preserved across instances.

This is achieved with the options:
* programs.bash.vteIntegration
* programs.zsh.vteIntegration

as it's best to keep this configuration unguarded by gnome3.enable
to support other vte terminals (such as elementary-terminal).
Note the distinction between Zsh and Bash doesn't include
a different script, as this script only supports those two shells.

nixos/modules/config/vte.nix

@@ -0,0 +1,52 @@
+# VTE
+
+{ config, pkgs, lib, ... }:
+
+with lib;
+
+let
+
+  vteInitSnippet = ''
+    # Show current working directory in VTE terminals window title.
+    # Supports both bash and zsh, requires interactive shell.
+    . ${pkgs.vte}/etc/profile.d/vte.sh
+  '';
+
+in
+
+{
+
+  options = {
+
+    programs.bash.vteIntegration = mkOption {
+      default = false;
+      type = types.bool;
+      description = ''
+        Whether to enable Bash integration for VTE terminals.
+        This allows it to preserve the current directory of the shell
+        across terminals.
+      '';
+    };
+
+    programs.zsh.vteIntegration = mkOption {
+      default = false;
+      type = types.bool;
+      description = ''
+        Whether to enable Zsh integration for VTE terminals.
+        This allows it to preserve the current directory of the shell
+        across terminals.
+      '';
+    };
+
+  };
+
+  config = mkMerge [
+    (mkIf config.programs.bash.vteIntegration {
+      programs.bash.interactiveShellInit = vteInitSnippet;
+    })
+
+    (mkIf config.programs.zsh.vteIntegration {
+      programs.zsh.interactiveShellInit = vteInitSnippet;
+    })
+  ];
+}

nixos/modules/module-list.nix

@@ -37,6 +37,7 @@
   ./config/unix-odbc-drivers.nix
   ./config/users-groups.nix
   ./config/vpnc.nix
+  ./config/vte.nix
   ./config/zram.nix
   ./hardware/acpilight.nix
   ./hardware/all-firmware.nix