nixos/system/env: add pager configurations

modules/nixos/system/env/default.nix

@@ -13,6 +13,14 @@ let
     mapAttrs
     ;
 
+  pagerArgs = [
+    "--RAW-CONTROL-CHARS" # Only allow colors.
+    "--wheel-lines=5"
+    "--LONG-PROMPT"
+    "--no-vbell"
+    " --wordwrap" # Wrap lines at spaces.
+  ];
+
   cfg = config.${namespace}.system.env;
 in
 {
@@ -57,6 +65,19 @@ in
         # Make some programs "XDG" compliant.
         LESSHISTFILE = "$XDG_CACHE_HOME/less.history";
         WGETRC = "$XDG_CONFIG_HOME/wgetrc";
+
+        MANPAGER = "nvim -c 'set ft=man bt=nowrite noswapfile nobk shada=\\\"NONE\\\" ro noma' +Man! -o -";
+        SYSTEMD_PAGERSECURE = "true";
+        PAGER = "less -FR";
+        LESS = concatStringsSep " " pagerArgs;
+        SYSTEMD_LESS = concatStringsSep " " (
+          pagerArgs
+          ++ [
+            "--quit-if-one-screen"
+            "--chop-long-lines"
+            "--no-init" # Keep content after quit.
+          ]
+        );
       };
     };
   };