(defun rem-comments (delimeter source destination) (with-open-file (in source :direction :input) (with-open-file (out destination :direction :output :if-exists :supersede) (do ((line (read-line in nil 'eof) (read-line in nil 'eof))) ((eql line 'eof)) (if (not (eql (read-from-string line) delimeter)) (format out line "~%"))))))