anchor.diff:              --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;
  -  };  
  +  };
   }
  -
  
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: 
  stdenv.mkDerivation rec {
    name = "hydra-${version}";
    version = "0.1pre26202";
    src = fetchurl {
      url = http://hydra.nixos.org/build/956221/download/2/hydra-0.1pre26202.tar.gz;
      sha256 = "0v727al406akn9n9ys5kl77kagr5l8yq9zi4nnn9nrcii8pavb99";
    };
  
    configureFlags = "--with-nix=${nix}";
  