cleanpath.scm

#! env -S csi -s

;;
;; Remove empty and duplicate entries from a colon-separated path.
;;
;; For example: ":a:b:b:::c:a::" --> "a:b:c"
;;

(require-extension data-structures)
(require-extension extras)
(require-extension srfi-1)

(let ([args (command-line-arguments)])
  (if (not (= (length args) 1))
      (let ([progname (program-name)])
        (write-string progname #f (current-error-port))
        (write-string ": command line error\n" #f (current-error-port))
        (write-string "Usage: "#f (current-error-port))
        (write-string progname #f (current-error-port))
        (write-string " PATH\n" #f (current-error-port))
        (exit 1))
      (let* ([dirty-path (car args)]
             [dirty-entries (string-split dirty-path ":")]
             [clean-entries (delete-duplicates dirty-entries)]
             [clean-path (string-intersperse clean-entries ":")])
        (write-string clean-path))))