;; then replace that region with the output.
(progn (setq buffer-read-only nil)
(delete-region (max start end) (point-max))
- (delete-region (point-min) (max start end))
+ (delete-region (point-min) (min start end))
(setq exit-status
(call-process-region (point-min) (point-max)
shell-file-name t t nil