val mkdtemp : t -> string -> string
(** create a temporary directory *)
+val wc_l : t -> string -> int
+(** count lines in a file *)
+
+val wc_w : t -> string -> int
+(** count words in a file *)
+
+val wc_c : t -> string -> int
+(** count characters in a file *)
+
+val head : t -> string -> string array
+(** return first 10 lines of a file *)
+
+val head_n : t -> int -> string -> string array
+(** return first N lines of a file *)
+
+val tail : t -> string -> string array
+(** return last 10 lines of a file *)
+
+val tail_n : t -> int -> string -> string array
+(** return last N lines of a file *)
+