implement Unmount; include "sys.m";include "draw.m"; FD: import Sys;Context: import Draw; Unmount: module{	init:	fn(ctxt: ref Context, argv: list of string);}; sys: Sys;stderr: ref FD; usage(){	sys->fprint(stderr, "Usage: unmount [source] target\n");} init(nil: ref Context, argv: list of string){	r: int; 	sys = load Sys Sys->PATH; 	stderr = sys->fildes(2); 	argv = tl argv; 	case len argv {	* =>		usage();		return;	1 =>		r = sys->unmount(nil, hd argv);	2 =>		r = sys->unmount(hd argv, hd tl argv);	}; 	if(r < 0)		sys->fprint(stderr, "unmount: %r\n");}