/*  * This file is part of the UCB release of Plan 9. It is subject to the license * terms in the LICENSE file found in the top-level directory of this * distribution and at http://akaros.cs.berkeley.edu/files/Plan9License. No * part of the UCB release of Plan 9, including this file, may be copied, * modified, propagated, or distributed except according to the terms contained * in the LICENSE file. */ #include <u.h>#include <libc.h> voidmain(void){	Fmt fmt;	char buf[512];	char *argv0, *args, *flags, *p, *p0;	int single;	Rune r;		argv0 = getenv("0");	if((p = strrchr(argv0, '/')) != nil)		argv0 = p+1;	flags = getenv("flagfmt");	args = getenv("args");		if(argv0 == nil){		fprint(2, "aux/usage: $0 not set\n");		exits("$0");	}	if(flags == nil)		flags = "";	if(args == nil)		args = ""; 	fmtfdinit(&fmt, 2, buf, sizeof buf);	fmtprint(&fmt, "usage: %s", argv0);	if(flags[0]){		single = 0;		for(p=flags; *p; ){			p += chartorune(&r, p);			if(*p == ',' || *p == 0){				if(!single){					fmtprint(&fmt, " [-");					single = 1;				}				fmtprint(&fmt, "%C", r);				if(*p == ',')					p++;				continue;			}			while(*p == ' ')				p++;			if(single){				fmtprint(&fmt, "]");				single = 0;			}			p0 = p;			p = strchr(p0, ',');			if(p == nil)				p = "";			else				*p++ = 0;			fmtprint(&fmt, " [-%C %s]", r, p0);		}		if(single)			fmtprint(&fmt, "]");	}	if(args)		fmtprint(&fmt, " %s", args);	fmtprint(&fmt, "\n");	fmtfdflush(&fmt);	exits("usage");}