diff --git a/pkgs/applications/misc/dunst/default.nix b/pkgs/applications/misc/dunst/default.nix
index cb594e494dba..1b61d75ddf2e 100644
--- a/pkgs/applications/misc/dunst/default.nix
+++ b/pkgs/applications/misc/dunst/default.nix
@@ -5,7 +5,7 @@
 
 stdenv.mkDerivation rec {
   rev = "6a3a855b48a3db64821d1cf8a91c5ee2815a2b2d";
-  name = "dunst-${rev}";
+  name = "dunst-0-${stdenv.lib.strings.substring 0 7 rev}";
 
   # 1.0.0 release doesn't include 100% CPU fix
   # https://github.com/knopwob/dunst/issues/98
diff --git a/pkgs/applications/networking/remote/freerdp/unstable.nix b/pkgs/applications/networking/remote/freerdp/unstable.nix
index ef8ddf8b0e3b..cce3d23d1945 100644
--- a/pkgs/applications/networking/remote/freerdp/unstable.nix
+++ b/pkgs/applications/networking/remote/freerdp/unstable.nix
@@ -25,7 +25,7 @@ assert printerSupport -> cups != null;
 let rev = "ec6effcb1e7759551cf31f5b18d768afc67db97d"; in
 
 stdenv.mkDerivation rec {
-  name = "freerdp-1.1pre${rev}";
+  name = "freerdp-1.1pre-${stdenv.lib.strings.substring 0 7 rev}";
 
   src = fetchgit {
     url = git://github.com/FreeRDP/FreeRDP.git;
diff --git a/pkgs/misc/uboot/guruplug.nix b/pkgs/misc/uboot/guruplug.nix
index b1f4cab7b735..258ba999bf88 100644
--- a/pkgs/misc/uboot/guruplug.nix
+++ b/pkgs/misc/uboot/guruplug.nix
@@ -10,7 +10,7 @@ let
   rev = "f106056095049c2c748c2a2797e5353295240e04";
 in
 stdenv.mkDerivation {
-  name = "uboot-guruplug-0.0pre${rev}";
+  name = "uboot-guruplug-0.0-pre-${stdenv.lib.strings.substring 0 7 rev}";
 
   src = fetchgit {
     url = "git://git.denx.de/u-boot-marvell.git";
diff --git a/pkgs/os-specific/linux/mcelog/default.nix b/pkgs/os-specific/linux/mcelog/default.nix
index b60b6134fdde..5c36bb097812 100644
--- a/pkgs/os-specific/linux/mcelog/default.nix
+++ b/pkgs/os-specific/linux/mcelog/default.nix
@@ -10,7 +10,7 @@
 let
 
   rev = "7fa99818367a6d17014b36d6f918ad848cbe7ce2";
-  version = "1.0pre-${rev}"; 
+  version = "1.0pre-${stdenv.lib.strings.substring 0 7 rev}"; 
   sha256 = "15eea3acd76190c7922c71028b31963221a2eefd8afa713879e191a26bc22ae7";
 
 in stdenv.mkDerivation {
diff --git a/pkgs/tools/backup/bup/default.nix b/pkgs/tools/backup/bup/default.nix
index e683df5a7fe1..54b089bd08e9 100644
--- a/pkgs/tools/backup/bup/default.nix
+++ b/pkgs/tools/backup/bup/default.nix
@@ -3,14 +3,16 @@
 
 assert par2Support -> par2cmdline != null;
 
+let rev = "96c6fa2a70425fff1e73d2e0945f8e242411ab58"; in
+
 with stdenv.lib;
 
 stdenv.mkDerivation {
-  name = "bup-0.25-rc1-107-g96c6fa2";
+  name = "bup-0.25-rc1-107-${stdenv.lib.strings.substring 0 7 rev}";
 
   src = fetchgit {
     url = "https://github.com/bup/bup.git";
-    rev = "96c6fa2a70425fff1e73d2e0945f8e242411ab58";
+    inherit rev;
     sha256 = "0d9hgyh1g5qcpdvnqv3a5zy67x79yx9qx557rxrnxyzqckp9v75n";
   };
 
diff --git a/pkgs/tools/networking/cjdns/default.nix b/pkgs/tools/networking/cjdns/default.nix
index a76e351efc49..ffe22a93d0d4 100644
--- a/pkgs/tools/networking/cjdns/default.nix
+++ b/pkgs/tools/networking/cjdns/default.nix
@@ -4,7 +4,7 @@ let
   rev = "f7b02ac0cc";
 in
 stdenv.mkDerivation {
-  name = "cjdns-git-20130620-${rev}";
+  name = "cjdns-git-20130620-${stdenv.lib.strings.substring 0 7 rev}";
 
   src = fetchgit {
     url = "https://github.com/cjdelisle/cjdns.git";