+val normalize_dir: string -> string (** add trailing "/" if missing *)
+val strip_trailing_slash: string -> string
+val strip_suffix: suffix:string -> string -> string
+
+val extension: string -> string (** @return string part after rightmost "." *)
+
+val temp_file_of_uri: string -> string * out_channel
+
+ (** execute a command and return first line of what it prints on stdout *)
+val backtick: string -> string
+