things all of them.

blah.lisp

(defun letter-freq (str)
    (let ((ht (make-hash-table)))
      (loop :for char :across str :do
            (incf (gethash char ht 0)))
      (maphash (lambda (k v)
                 (format t "~@C: ~D~%" k v))
               ht)))

(defun letter-freq-in-file (file)
  (with-open-file (stream file)
    (let ((str (make-string (file-length stream))))
      (read-sequence str stream)
      (letter-freq str))))

(letter-freq-in-file "test.txt")