diff --git a/modules/examples/lnl.nix b/modules/examples/lnl.nix
index 54f6c54..a9f081d 100644
--- a/modules/examples/lnl.nix
+++ b/modules/examples/lnl.nix
@@ -42,7 +42,7 @@
   services.activate-system.enable = true;
 
   programs.tmux.enable = true;
-  programs.tmux.loginShell = "${config.programs.zsh.shell} -l";
+  programs.tmux.loginShell = "$SHELL -l";
   programs.tmux.enableSensible = true;
   programs.tmux.enableMouse = true;
   programs.tmux.enableFzf = true;
@@ -58,6 +58,11 @@
   programs.zsh.enable = true;
   programs.zsh.enableBashCompletion = true;
 
+  programs.zsh.variables.cfg = "$HOME/.nixpkgs/darwin-config.nix";
+  programs.zsh.variables.darwin = "$HOME/.nix-defexpr/darwin";
+  programs.zsh.variables.pkgs = "$HOME/.nix-defexpr/nixpkgs";
+
+
   programs.zsh.promptInit = ''
     autoload -U promptinit && promptinit
 
@@ -65,19 +70,7 @@
     RPROMPT='%F{green}%~%f'
   '';
 
-  programs.zsh.shellInit = ''
-    cfg=$HOME/.nixpkgs/darwin-config.nix
-    darwin=$HOME/.nix-defexpr/darwin
-    pkgs=$HOME/.nix-defexpr/nixpkgs
-  '';
-
   programs.zsh.loginShellInit = ''
-
-    bindkey -e
-    setopt autocd
-
-    autoload -U compinit && compinit
-
     nix () {
       cmd=$1
       shift
@@ -102,12 +95,8 @@
   '';
 
   programs.zsh.interactiveShellInit = ''
-    # history defaults
-    SAVEHIST=2000
-    HISTSIZE=2000
-    HISTFILE=$HOME/.zsh_history
-
-    setopt HIST_IGNORE_DUPS SHARE_HISTORY HIST_FCNTL_LOCK
+    bindkey -e
+    setopt AUTOCD
   '';
 
   environment.variables.EDITOR = "vim";
@@ -140,6 +129,7 @@
 
         mkdir -p $out/bin
         makeWrapper ${pkgs.tmux}/bin/tmux $out/bin/tmux \
+          --set __ETC_BASHRC_SOURCED "" \
           --set __ETC_ZPROFILE_SOURCED  "" \
           --set __ETC_ZSHENV_SOURCED "" \
           --set __ETC_ZSHRC_SOURCED "" \
diff --git a/modules/programs/bash.nix b/modules/programs/bash.nix
index 2231401..7a021ff 100644
--- a/modules/programs/bash.nix
+++ b/modules/programs/bash.nix
@@ -6,7 +6,7 @@ let
 
   cfg = config.programs.bash;
 
-  bash = pkgs.runCommand pkgs.zsh.name
+  shell = pkgs.runCommand pkgs.zsh.name
     { buildInputs = [ pkgs.makeWrapper ]; }
     ''
       source $stdenv/setup
@@ -39,14 +39,6 @@ in
       '';
     };
 
-    programs.bash.shell = mkOption {
-      type = types.path;
-      default = "${bash}/bin/bash";
-      description = ''
-        Zsh shell to use.
-      '';
-    };
-
     programs.bash.interactiveShellInit = mkOption {
       default = "";
       description = ''
@@ -64,7 +56,7 @@ in
         pkgs.bash
       ];
 
-    environment.variables.SHELL = mkDefault "${cfg.shell}";
+    environment.variables.SHELL = mkDefault "${shell}/bin/bash";
 
     environment.etc."bashrc".text = ''
       # /etc/bashrc: DO NOT EDIT -- this file has been generated automatically.
diff --git a/modules/programs/zsh.nix b/modules/programs/zsh.nix
index 1990e4d..aeea21d 100644
--- a/modules/programs/zsh.nix
+++ b/modules/programs/zsh.nix
@@ -6,7 +6,10 @@ let
 
   cfg = config.programs.zsh;
 
-  zsh = pkgs.runCommand pkgs.zsh.name
+  zshVariables =
+    mapAttrsToList (n: v: ''${n}="${v}"'') cfg.variables;
+
+  shell = pkgs.runCommand pkgs.zsh.name
     { buildInputs = [ pkgs.makeWrapper ]; }
     ''
       source $stdenv/setup
@@ -55,12 +58,17 @@ in
       '';
     };
 
-    programs.zsh.shell = mkOption {
-      type = types.path;
-      default = "${zsh}/bin/zsh";
+    programs.zsh.variables = mkOption {
+      type = types.attrsOf (types.either types.str (types.listOf types.str));
+      default = {};
       description = ''
-        Zsh shell to use.
+        A set of environment variables used in the global environment.
+        These variables will be set on shell initialisation.
+        The value of each variable can be either a string or a list of
+        strings.  The latter is concatenated, interspersed with colon
+        characters.
       '';
+      apply = mapAttrs (n: v: if isList v then concatStringsSep ":" v else v);
     };
 
     programs.zsh.shellInit = mkOption {
@@ -120,7 +128,7 @@ in
         pkgs.zsh
       ];
 
-    environment.variables.SHELL = mkDefault "${cfg.shell}";
+    environment.variables.SHELL = mkDefault "${shell}/bin/zsh";
 
     environment.etc."zshenv".text = ''
       # /etc/zshenv: DO NOT EDIT -- this file has been generated automatically.
@@ -147,6 +155,8 @@ in
       if [ -n "$__ETC_ZPROFILE_SOURCED" ]; then return; fi
       __ETC_ZPROFILE_SOURCED=1
 
+      ${concatStringsSep "\n" zshVariables}
+
       ${cfg.loginShellInit}
 
       # Read system-wide modifications.