1 #include <u.h>
2 #include <libc.h>
3 
4 void
5 main(int argc, char **argv)
6 {
7 	Fmt fmt;
8 	char buf[512];
9 	char *argv0, *args, *flags, *p, *p0;
10 	int single;
11 	Rune r;
12 
13 	argv0 = getenv("0");
14 	if(argv0 == nil) {
15 		if(argc > 1)
16 			argv0 = argv[1];
17 		else
18 			argv0 = "unknown-program-name";
19 	}
20 	if((p = strrchr(argv0, '/')) != nil)
21 		argv0 = p+1;
22 	flags = getenv("flagfmt");
23 	args = getenv("args");
24 
25 	if(argv0 == nil){
26 		fprint(2, "aux/usage: $0 not set\n");
27 		exits("$0");
28 	}
29 	if(flags == nil)
30 		flags = "";
31 	if(args == nil)
32 		args = "";
33 
34 	fmtfdinit(&fmt, 2, buf, sizeof buf);
35 	fmtprint(&fmt, "usage: %s", argv0);
36 	if(flags[0]){
37 		single = 0;
38 		for(p=flags; *p; ){
39 			p += chartorune(&r, p);
40 			if(*p == ',' || *p == 0){
41 				if(!single){
42 					fmtprint(&fmt, " [-");
43 					single = 1;
44 				}
45 				fmtprint(&fmt, "%C", r);
46 				if(*p == ',')
47 					p++;
48 				continue;
49 			}
50 			while(*p == ' ')
51 				p++;
52 			if(single){
53 				fmtprint(&fmt, "]");
54 				single = 0;
55 			}
56 			p0 = p;
57 			p = strchr(p0, ',');
58 			if(p == nil)
59 				p = "";
60 			else
61 				*p++ = 0;
62 			fmtprint(&fmt, " [-%C %s]", r, p0);
63 		}
64 		if(single)
65 			fmtprint(&fmt, "]");
66 	}
67 	if(args)
68 		fmtprint(&fmt, " %s", args);
69 	fmtprint(&fmt, "\n");
70 	fmtfdflush(&fmt);
71 	exits("usage");
72 }