anchor.diff:              source = mkOption {
                 type = types.path;
                 description = ''
  -                Path of the source file. Note, the file name must not
  -                start with a period since Nix will not allow such
  -                names in the Nix store.
  +                Path of the source file. The file name must not start
  +                with a period since Nix will not allow such names in
  +                the Nix store.
  +                </para><para>
  +                This may refer to a directory.
                 '';
               };
   
  
positive.code:           oldGenFiles="$2"
            shift 2
            for sourcePath in "$@" ; do
              relativePath="$(realpath --relative-to "$oldGenFiles" "$sourcePath")"
              targetPath="$HOME/$relativePath"
              if [[ -f "$newGenFiles/$relativePath" ]] ; then
                $VERBOSE_ECHO "Checking $targetPath  exists"
              else
                echo "Checking $targetPath  gone (deleting)"
  
negative.code:           function linkNewGen() {
              local newGenFiles
              newGenFiles="$(readlink -e "$newGenPath/home-files")"
              find "$newGenFiles" -type f -print0 -or -type l -print0 \
                | xargs -0 bash ${link} "$newGenFiles"
            }
  
  