3 files changed, 4 insertions, 1 deletions
diff --git a/pkgs/tools/system/at/default.nix b/pkgs/tools/system/at/default.nix
index 9a6e610389b..9991adf4013 100644
--- a/pkgs/tools/system/at/default.nix
+++ b/pkgs/tools/system/at/default.nix
@@ -33,5 +33,6 @@ stdenv.mkDerivation {
     description = ''The classical Unix `at' job scheduling command'';
     license = stdenv.lib.licenses.gpl2Plus;
     homepage = http://packages.qa.debian.org/at;
+    platforms = stdenv.lib.platforms.linux;
   };
 }
diff --git a/pkgs/tools/system/cron/default.nix b/pkgs/tools/system/cron/default.nix
index e465b16b614..998be45d9c6 100644
--- a/pkgs/tools/system/cron/default.nix
+++ b/pkgs/tools/system/cron/default.nix
@@ -20,8 +20,9 @@ stdenv.mkDerivation {
   '';
 
   preInstall = "mkdir -p $out/bin $out/sbin $out/share/man/man1 $out/share/man/man5 $out/share/man/man8";
-  
+
   meta = {
     description = "Daemon for running commands at specific times (Vixie Cron)";
+    platforms = stdenv.lib.platforms.linux;
   };
 }
diff --git a/pkgs/tools/system/which/default.nix b/pkgs/tools/system/which/default.nix
index fc40cd4722b..6662d90e8bd 100644
--- a/pkgs/tools/system/which/default.nix
+++ b/pkgs/tools/system/which/default.nix
@@ -10,5 +10,6 @@ stdenv.mkDerivation {
 
   meta = {
     homepage = http://ftp.gnu.org/gnu/which/;
+    platforms = stdenv.lib.platforms.all;
   };
 }