diff --git a/pkgs/tools/X11/dex/default.nix b/pkgs/tools/X11/dex/default.nix
index 2a3a406135b..fd0c0503de9 100644
--- a/pkgs/tools/X11/dex/default.nix
+++ b/pkgs/tools/X11/dex/default.nix
@@ -16,9 +16,10 @@ stdenv.mkDerivation rec {
   nativeBuildInputs = [ python3.pkgs.sphinx ];
   makeFlags = [ "PREFIX=$(out)" "VERSION=$(version)" ];
 
-  meta = {
+  meta = with stdenv.lib; {
     description = "A program to generate and execute DesktopEntry files of the Application type";
     homepage = https://github.com/jceb/dex;
-    platforms = stdenv.lib.platforms.linux;
+    platforms = platforms.linux;
+    license = licenses.gpl3Plus;
   };
 }
diff --git a/pkgs/tools/X11/virtualgl/default.nix b/pkgs/tools/X11/virtualgl/default.nix
index b0d017acf84..aa839e6d684 100644
--- a/pkgs/tools/X11/virtualgl/default.nix
+++ b/pkgs/tools/X11/virtualgl/default.nix
@@ -19,5 +19,6 @@ stdenv.mkDerivation {
 
   meta = {
     platforms = stdenv.lib.platforms.linux;
+    inherit (virtualglLib.meta) license;
   };
 }
diff --git a/pkgs/tools/X11/virtualgl/lib.nix b/pkgs/tools/X11/virtualgl/lib.nix
index c552011f384..4c911e75633 100644
--- a/pkgs/tools/X11/virtualgl/lib.nix
+++ b/pkgs/tools/X11/virtualgl/lib.nix
@@ -22,7 +22,7 @@ stdenv.mkDerivation rec {
   meta = with stdenv.lib; {
     homepage = http://www.virtualgl.org/;
     description = "X11 GL rendering in a remote computer with full 3D hw acceleration";
-    license = licenses.free; # many parts under different free licenses
+    license = licenses.wxWindows;
     platforms = platforms.linux;
     maintainers = with maintainers; [ abbradar ];
   };
diff --git a/pkgs/tools/X11/x11vnc/default.nix b/pkgs/tools/X11/x11vnc/default.nix
index 2d319cccf20..2dc6d8ffd78 100644
--- a/pkgs/tools/X11/x11vnc/default.nix
+++ b/pkgs/tools/X11/x11vnc/default.nix
@@ -26,9 +26,10 @@ stdenv.mkDerivation rec {
     sed -i -e '/#!\/bin\/sh/a"PATH=${xorg.xdpyinfo}\/bin:${xorg.xauth}\/bin:$PATH\\n"' -e 's|/bin/su|/run/wrappers/bin/su|g' x11vnc/ssltools.h
   '';
 
-  meta = {
+  meta = with stdenv.lib; {
     description = "A VNC server connected to a real X11 screen";
     homepage = http://www.karlrunge.com/x11vnc/;
-    platforms = stdenv.lib.platforms.linux;
+    platforms = platforms.linux;
+    license = licenses.gpl2;
   };
 }
diff --git a/pkgs/tools/X11/x2vnc/default.nix b/pkgs/tools/X11/x2vnc/default.nix
index 2703379a23b..f3ab23d364c 100644
--- a/pkgs/tools/X11/x2vnc/default.nix
+++ b/pkgs/tools/X11/x2vnc/default.nix
@@ -15,9 +15,10 @@ stdenv.mkDerivation rec {
 
   hardeningDisable = [ "format" ];
 
-  meta = {
+  meta = with stdenv.lib; {
     homepage = http://fredrik.hubbe.net/x2vnc.html;
     description = "A program to control a remote VNC server";
-    platforms = stdenv.lib.platforms.unix;
+    platforms = platforms.unix;
+    license = licenses.gpl2;
   };
 }
diff --git a/pkgs/tools/X11/xpra/default.nix b/pkgs/tools/X11/xpra/default.nix
index fd7f70004db..23270793b34 100644
--- a/pkgs/tools/X11/xpra/default.nix
+++ b/pkgs/tools/X11/xpra/default.nix
@@ -81,5 +81,6 @@ in buildPythonApplication rec {
     description = "Persistent remote applications for X";
     platforms = platforms.linux;
     maintainers = with maintainers; [ tstrobel offline ];
+    license = licenses.gpl2;
   };
 }
diff --git a/pkgs/tools/X11/xpra/gtk3.nix b/pkgs/tools/X11/xpra/gtk3.nix
index 16693b08e11..ceba4269e80 100644
--- a/pkgs/tools/X11/xpra/gtk3.nix
+++ b/pkgs/tools/X11/xpra/gtk3.nix
@@ -68,11 +68,12 @@ buildPythonApplication rec {
   #'';
 
 
-  meta = {
+  meta = with stdenv.lib; {
     homepage = http://xpra.org/;
     downloadPage = "https://xpra.org/src/";
     downloadURLRegexp = "xpra-.*[.]tar[.]xz$";
     description = "Persistent remote applications for X";
-    platforms = stdenv.lib.platforms.linux;
+    platforms = platforms.linux;
+    license = licenses.gpl2;
   };
 }
diff --git a/pkgs/tools/X11/xpra/libfakeXinerama.nix b/pkgs/tools/X11/xpra/libfakeXinerama.nix
index 4ca509f8b93..d6fab2b1910 100644
--- a/pkgs/tools/X11/xpra/libfakeXinerama.nix
+++ b/pkgs/tools/X11/xpra/libfakeXinerama.nix
@@ -24,10 +24,11 @@ stdenv.mkDerivation  rec {
     ln -s libXinerama.so.1 $out/lib/libXinerama.so
   '';
 
-  meta = {
+  meta = with stdenv.lib; {
     homepage = http://xpra.org/;
     description = "fakeXinerama for Xpra";
-    platforms = stdenv.lib.platforms.linux;
-    maintainers = with stdenv.lib.maintainers; [ tstrobel ];
+    platforms = platforms.linux;
+    maintainers = [ maintainers.tstrobel ];
+    license = licenses.gpl2;
   };
 }
diff --git a/pkgs/tools/system/dd_rescue/default.nix b/pkgs/tools/system/dd_rescue/default.nix
index 1ea574dbe8e..e0d11769fd9 100644
--- a/pkgs/tools/system/dd_rescue/default.nix
+++ b/pkgs/tools/system/dd_rescue/default.nix
@@ -20,7 +20,7 @@ stdenv.mkDerivation rec {
     substituteInPlace Makefile \
       --replace "\$(DESTDIR)/usr" "$out" \
       --replace "-o root" "" \
-      --replace "-g root" "" 
+      --replace "-g root" ""
   '';
   makeFlags = [ "LIBDIR=$out" ];
 
@@ -29,12 +29,13 @@ stdenv.mkDerivation rec {
     tar xf "${dd_rhelp_src}" -C "$out/share/dd_rescue"
     cp "$out/share/dd_rescue"/dd_rhelp*/dd_rhelp "$out/bin"
   '';
-      
+
   meta = with stdenv.lib; {
     description = "A tool to copy data from a damaged block device";
     maintainers = with maintainers; [ raskin domenkozar ];
     platforms = platforms.linux;
-    downloadPage = "http://www.garloff.de/kurt/linux/ddrescue/";
+    homepage = "http://www.garloff.de/kurt/linux/ddrescue/";
+    license = licenses.gpl2Plus;
     inherit version;
     updateWalker = true;
   };
diff --git a/pkgs/tools/system/localtime/default.nix b/pkgs/tools/system/localtime/default.nix
index c49054f3a67..442b9a42f2b 100644
--- a/pkgs/tools/system/localtime/default.nix
+++ b/pkgs/tools/system/localtime/default.nix
@@ -9,7 +9,7 @@ stdenv.mkDerivation {
     rev = "2e7b4317c723406bd75b2a1d640219ab9f8090ce";
     sha256 = "04fyna8p7q7skzx9fzmncd6gx7x5pwa9jh8a84hpljlvj0kldfs8";
   };
-  
+
   buildInputs = [ go systemd polkit m4 removeReferencesTo ];
   disallowedRequisites = [ go ];
 
@@ -19,9 +19,10 @@ stdenv.mkDerivation {
     find $out/bin -type f -exec remove-references-to -t ${go} '{}' +
   '';
 
-  meta = {
+  meta = with stdenv.lib; {
     description = "A daemon for keeping the system timezone up-to-date based on the current location";
     homepage = https://github.com/Stebalien/localtime;
-    platforms = stdenv.lib.platforms.linux;
+    platforms = platforms.linux;
+    license = licenses.gpl3;
   };
 }
diff --git a/pkgs/tools/system/sg3_utils/default.nix b/pkgs/tools/system/sg3_utils/default.nix
index ca1af7a74e4..8be7203fb3d 100644
--- a/pkgs/tools/system/sg3_utils/default.nix
+++ b/pkgs/tools/system/sg3_utils/default.nix
@@ -8,10 +8,10 @@ stdenv.mkDerivation rec {
     sha256 = "1wwy7iiz1lvc32c777yd4vp0c0dqfdlm5jrsm3aa62xx141pmjqx";
   };
 
-  meta = {
+  meta = with stdenv.lib; {
     homepage = http://sg.danny.cz/sg/;
     description = "Utilities that send SCSI commands to devices";
-    platforms = stdenv.lib.platforms.linux;
-    maintainers = [ ];
+    platforms = platforms.linux;
+    license = with licenses; [ bsd2 gpl2Plus ];
   };
 }
diff --git a/pkgs/tools/system/vbetool/default.nix b/pkgs/tools/system/vbetool/default.nix
index c30a7b14e89..32cf56a1d74 100644
--- a/pkgs/tools/system/vbetool/default.nix
+++ b/pkgs/tools/system/vbetool/default.nix
@@ -22,5 +22,6 @@ stdenv.mkDerivation rec {
     homepage = http://www.codon.org.uk/~mjg59/vbetool/;
     maintainers = [ maintainers.raskin ];
     platforms = platforms.linux;
+    license = licenses.gpl2;
   };
 }
diff --git a/pkgs/tools/video/flvtool2/default.nix b/pkgs/tools/video/flvtool2/default.nix
index 975e13b65da..037e07c7228 100644
--- a/pkgs/tools/video/flvtool2/default.nix
+++ b/pkgs/tools/video/flvtool2/default.nix
@@ -1,4 +1,4 @@
-{ buildRubyGem, ruby }:
+{ lib, buildRubyGem, ruby }:
 
 buildRubyGem rec {
   inherit ruby;
@@ -12,5 +12,6 @@ buildRubyGem rec {
     homepage = https://github.com/unnu/flvtool2;
     description = "A tool to manipulate Macromedia Flash Video files";
     platforms = ruby.meta.platforms;
+    license = lib.licenses.bsd3;
   };
 }