script to DNS-block certain sites as a measure against me procrastinating too much

nixos/configuration.nix

@@ -5,7 +5,7 @@
 { config, pkgs, ... }:
 
 let
-  unstable = import <nixos-unstable> {};
+  unstable = import <nixos-unstable> { };
 
 in
 {
@@ -78,6 +78,7 @@ in
   programs.wireshark =
     {
       enable = true;
+      package = pkgs.wireshark;
     };
 
   programs.adb.enable = true;
@@ -95,8 +96,8 @@ in
   # Open ports in the firewall.
   # networking.firewall.allowedTCPPorts = [ ... ];
   # networking.firewall.allowedUDPPorts = [ ... ];
-  networking.firewall.allowedTCPPortRanges = [ { from = 1714; to = 1764; } ];
-  networking.firewall.allowedUDPPortRanges = [ { from = 1714; to = 1764; } ]; # for KDE connect
+  networking.firewall.allowedTCPPortRanges = [{ from = 1714; to = 1764; }];
+  networking.firewall.allowedUDPPortRanges = [{ from = 1714; to = 1764; }]; # for KDE connect
   # Or disable the firewall altogether.
   # networking.firewall.enable = false;
 
@@ -180,9 +181,36 @@ in
   services.smartd =
     {
       enable = true;
-      devices = [ { device = "/dev/sda"; } { device = "/dev/sdb"; } ];
+      devices = [{ device = "/dev/sda"; } { device = "/dev/sdb"; }];
     };
 
+  # block certain sites to prevent procrastination
+  systemd.services.procrastinationstop = {
+    serviceConfig.Type = "oneshot";
+    wantedBy = [ ];
+    script = ''
+      ln -sf ${pkgs.writeText "blockedHosts" ''
+        ::1   twitter.com
+        127.0.0.1   twitter.com
+        ::1   api.twitter.com
+        127.0.0.1   api.twitter.com
+        ::1   toot.matereal.eu
+        127.0.0.1   toot.matereal.eu
+        ::1   tagesschau.de
+        127.0.0.1   tagesschau.de
+        ::1   dnn.de
+        127.0.0.1   dnn.de
+        ''} /etc/hosts
+    '';
+  };
+
+  systemd.services.procrastinationstart = {
+    serviceConfig.Type = "oneshot";
+    wantedBy = [ ];
+    script = ''
+      ln -sf /etc/static/hosts /etc/hosts
+    '';
+  };
 
   fonts = {
     fontDir.enable = true;