user/shutils/which.c

   1 #include <stdio.h>
   2 #include <stdlib.h>
   3 #include <string.h>
   4 #include <unistd.h>
   5
   6 int
   7 main(argc,argv)
   8 int argc;
   9 char ** argv;
  10 {
  11         char *envpath;
  12         char *path, *cp;
  13         char buf[200];
  14         char patbuf[512];
  15         int quit, found;
  16
  17         if (argc < 2) {
  18                 write(STDERR_FILENO, "Usage: which cmd [cmd, ..]\n", 37);
  19                 exit(1);
  20         }
  21         if ((envpath = getenv("PATH")) == 0) {
  22                 envpath = ".";
  23         }
  24
  25         argv[argc] = 0;
  26         for(argv++ ; *argv; argv++) {
  27
  28                 strcpy(patbuf, envpath);
  29                 cp = path = patbuf;
  30                 quit = found = 0;
  31
  32                 while(!quit) {
  33                         cp = index(path, ':');
  34                         if (cp == NULL) {
  35                                 quit++;
  36                         } else {
  37                                 *cp = '\0';
  38                         }
  39                         sprintf(buf, "%s/%s", (*path ? path:"."), *argv);
  40                         path = ++cp;
  41
  42                         if (access(buf, 1) == 0) {
  43                                 printf("%s\n", buf);
  44                                 found++;
  45                         }
  46                 }
  47                 if (!found) {
  48                         printf("No %s in %s\n", *argv, envpath);
  49                 }
  50         }
  51         exit(0);
  52 }