anchor.diff:  
   stdenv.mkDerivation rec {
     name = "hydra-${version}";
  -  version = "0.1pre25566";
  +  version = "0.1pre26202";
     src = fetchurl {
  -    url = http://hydra.nixos.org/build/858318/download/1/hydra-0.1pre25566.tar.gz;
  -    sha256 = "6b2dc48d609a69dec117debbd185d71bfb092bc7078f8ca59e29aaf3c9591ca7";
  +    url = http://hydra.nixos.org/build/956221/download/2/hydra-0.1pre26202.tar.gz;
  +    sha256 = "0v727al406akn9n9ys5kl77kagr5l8yq9zi4nnn9nrcii8pavb99";
     };
   
     configureFlags = "--with-nix=${nix}";
  
positive.code:     rpm dpkg cdrkit]));
  
    postInstall = ''
      for i in $out/bin/*; do
          wrapProgram $i \
              --prefix PERL5LIB ':' $out/libexec/hydra/lib:$PERL5LIB \
              --prefix PATH ':' $out/bin:$hydraPath \
  
negative.code:             --set HYDRA_HOME $out/libexec/hydra \
              --set NIX_RELEASE ${nix.name}
      done
    '';
  
    meta = {
      description = "Hydra, the Nix-based continuous integration system";
      homepage = http://nixos.org/hydra/;
      license = "GPLv3+";
      platforms = stdenv.lib.platforms.linux;
    };
  }
  