getshells.lsp

getshells.lsp

(defun inc (val)
  (if val (1+ val) 1))

(defun split-passwd (file)
  (with-open-file (stream file :if-does-not-exist nil)
    (when stream
      (loop for line = (read-line stream nil)
            while line
            collect (subseq line (1+ (position #\: line :from-end t)))))))

(defun occurrences (lst)
  (let ((table (make-hash-table :test #'equal)))
    (loop for shell in lst
          do (pushnew shell (getf table shell) :test #'equal))
    table))

(defun main (&rest argv)
  (time
   (dolist (k (hash-table-keys (occurrences (split-passwd "passwd"))))
     (format t "~a : ~a~%" k (getf (occurrences (split-passwd "passwd")) k)))))

(sb-ext:save-lisp-and-die "optimized" :executable t :toplevel #'main :compression 9)