Please share that script when you do it. It might be fancy to read man pages when one is bored instead of watching something as the randomness might dig some cool facts of the system for you which you did not know before hand.
dir="/bin"; man $(ls $dir |sed -n "$(echo $(( $RANDOM % $(ls $dir |wc -l | awk "{ print $1; }" ) + 1 )) )p")
;; Taken from http://emacswiki.org/emacs/ElispCookbook#toc57
(defun directory-dirs (dir)
"Find all directories in DIR."
(unless (file-directory-p dir)
(error "Not a directory `%s'" dir))
(let ((dir (directory-file-name dir))
(dirs '())
(files (directory-files dir nil nil t)))
(dolist (file files)
(unless (member file '("." ".."))
(let ((file (concat dir "/" file)))
(when (file-directory-p file)
(setq dirs (append (cons file
(directory-dirs file))
dirs))))))
dirs))
;; Taken from
;; http://stackoverflow.com/questions/3815467/stripping-duplicate-elements-in-a-list-of-strings-in-elisp
(defun strip-duplicates (list)
(let ((new-list nil))
(while list
(when (and (car list) (not (member (car list) new-list)))
(setq new-list (cons (car list) new-list)))
(setq list (cdr list)))
(nreverse new-list)))
;; Display a random manual page
(defun open-random-man-page ()
(interactive)
;; Get manual page paths from the environment.
(setq man-paths (parse-colon-path (getenv "MANPATH")))
(setq man-dirs ())
(dolist (man-path man-paths)
(setq man-dirs (append man-dirs (directory-dirs man-path))))
;; Get a list of files in manual page paths.
(setq files ())
(dolist (man-dir man-dirs)
(setq files (append files (directory-files man-dir nil "^[^\.].*"))))
;; Fixup the files to be a list of man pages.
(setq man-pages ())
(dolist (file files)
(setq man-pages (cons (car (split-string file "\\." t)) man-pages)))
(setq man-pages (strip-duplicates man-pages))
(random t)
(man (nth (random (length man-pages)) man-pages)))