anchor.diff:  
   	  (with-open-file (out "xargs-program.sh" :if-exists if-exists :direction :output)
   	    (format out "#!/bin/sh~%")
  -	    (format out "~S `cat ~S` $1 $2 $3~%"
  +	    (format out "~S --chains-group-size ~d `cat ~S` $1 $2 $3~%"
   		    (namestring program-path)
  +                    group-size
   		    (namestring (merge-pathnames "xargs-program-arguments"))))
   
   	  (with-open-file (out "xargs.sh":if-exists if-exists :direction :output)
  
positive.code:   #- (or darwin linux)
    (error "XARGS-SEQUENCE is not supported on your operating system."))
  
  (defun prepare-xargs-script (directory area tree program &key (if-exists :error if-exists-p))
    (declare (type (member :error :supersede :supersede-all) if-exists))
    (let ((program-path (if (listp program)
  			  (apply #'lisp-executable-pathname program)
  
negative.code: 		 :when (plusp count)
  		 :do
  		 (format out "~A | xargs -L 1 `cat ~S` /bin/sh ~S ~S ~d~%"
  			 (xargs-sequence (floor count group-size))
  			 (namestring (merge-pathnames "xargs-arguments"))
  			 (namestring (merge-pathnames "xargs-program.sh"))
  			 (namestring (merge-pathnames "xargs-data.sexp"))
  