anchor.diff:  
     meta = with stdenv.lib; {
       description = "Shell tool for executing jobs in parallel";
  -
       longDescription =
         '' GNU Parallel is a shell tool for executing jobs in parallel.  A job
            is typically a single command or a small script that has to be run
  
positive.code:          it possible to use output from GNU Parallel as input for other
           programs.
        '';
  
      homepage = http://www.gnu.org/software/parallel/;
  
      license = licenses.gpl3Plus;
  
      platforms = platforms.all;
      maintainers = with maintainers; [ pSub ];
    };
  
negative.code: { fetchurl, stdenv, perl }:
  
  stdenv.mkDerivation rec {
    name = "parallel-20150522";
  
    src = fetchurl {
      url = "mirror://gnu/parallel/${name}.tar.bz2";
      sha256 = "01pkckrad3d2i7mkw98zxymp22rsngyjknhh18i4m6hq82bijjjc";
    };
  
    patchPhase =
  