; basename path [suffix]: the last part of a path, as POSIX's, its slashes
; at the end gone first; the suffix goes too when it is not all of it.
(def trim-slashes
  (fn (s)
    (let ((n (str-len s)))
      (if (and (> n 1) (= (str-sub s (- n 1)) "/"))
        (trim-slashes (str-sub s 0 (- n 1)))
        s))))

(if (= (length ARGS) 0)
  (echo "usage: basename <path> [<suffix>]")
  (let ((p (trim-slashes (nth ARGS 0))))
    (if (= p "/")
      (echo "/")
      (let ((parts (str-split "/" p))
            (base (nth parts (- (length parts) 1)))
            (suf (if (> (length ARGS) 1) (nth ARGS 1) ""))
            (bn (str-len base))
            (sn (str-len suf)))
        (if (and (> sn 0) (> bn sn) (= (str-sub base (- bn sn)) suf))
          (echo (str-sub base 0 (- bn sn)))
          (echo base))))))