sys/src/cmd/aux/usage.c

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