Don't use "with licenses;" for single licences

And don't use square brackets on such lines.

pkgs/tools/system/bootchart/default.nix

@@ -31,7 +31,7 @@ stdenv.mkDerivation rec {
   meta = with stdenv.lib; {
     homepage = http://www.bootchart.org/;
     description = "Performance analysis and visualization of the GNU/Linux boot process";
-    license = with licenses; gpl2Plus;
+    license = licenses.gpl2Plus;
   };
 
 }

pkgs/tools/system/dog/default.nix

@@ -18,7 +18,7 @@ stdenv.mkDerivation rec {
   meta = with stdenv.lib; {
     homepage = "http://lwn.net/Articles/421072/";
     description = "cat replacement";
-    license = with licenses; gpl2Plus;
+    license = licenses.gpl2Plus;
     maintainers = with maintainers; [ qknight ];
     platforms = with platforms; all;
   };

pkgs/tools/system/foremost/default.nix

@@ -22,7 +22,7 @@ stdenv.mkDerivation rec {
       reliable and faster recovery.
     '';
     homepage = http://foremost.sourceforge.net/;
-    license = with licenses; publicDomain;
+    license = licenses.publicDomain;
     platforms = with platforms; linux;
     maintainers = with maintainers; [ nckx ];
   };

pkgs/tools/system/stress-ng/default.nix

@@ -35,7 +35,7 @@ stdenv.mkDerivation rec {
     '';
     homepage = http://kernel.ubuntu.com/~cking/stress-ng;
     downloadPage = http://kernel.ubuntu.com/~cking/tarballs/stress-ng/;
-    license = with licenses; gpl2Plus;
+    license = licenses.gpl2Plus;
     platforms = with platforms; linux;
     maintainers = with maintainers; [ nckx ];
   };

pkgs/tools/system/suid-chroot/default.nix

@@ -16,7 +16,7 @@ stdenv.mkDerivation rec {
   meta = with stdenv.lib; {
     inherit version;
     description = "Setuid-safe wrapper for chroot";
-    license = with licenses; gpl2Plus;
+    license = licenses.gpl2Plus;
     maintainers = with maintainers; [ nckx ];
   };
 }

pkgs/tools/system/tm/default.nix

@@ -20,7 +20,7 @@ stdenv.mkDerivation {
   meta = with stdenv.lib; {
     homepage = "http://vicerveza.homeunix.net/~viric/soft/tm";
     description = "terminal mixer - multiplexer for the i/o of terminal applications";
-    license = with licenses; gpl2;
+    license = licenses.gpl2;
     maintainers = with maintainers; [ viric ];
     platforms = with platforms; all;
   };

pkgs/tools/system/ts/default.nix

@@ -23,7 +23,7 @@ stdenv.mkDerivation rec {
   meta = with stdenv.lib; {
     homepage = "http://vicerveza.homeunix.net/~viric/soft/ts";
     description = "task spooler - batch queue";
-    license = with licenses; gpl2;
+    license = licenses.gpl2;
     maintainers = with maintainers; [ viric ];
     platforms = with platforms; all;
   };

pkgs/tools/system/uptimed/default.nix

@@ -20,7 +20,7 @@ stdenv.mkDerivation {
       which can also easily be used to show your records on a web page.
     '';
     homepage = https://github.com/rpodgorny/uptimed/;
-    license = with licenses; gpl2;
+    license = licenses.gpl2;
     platforms = with platforms; linux;
   };