#include <netdb.h>
#include <stdio.h>
#include <stdlib.h>

int main(int argc, char **argv) {
  char *group, *host, *hostp, *userp, *domainp;

  if (argc == 1) {
    fprintf(stderr, "Usage: netgroups <netgroup> [<hostname>]\n");
    exit(1);
  }

  /* What group do we want? */
  group = argv[1];
  if (*group == '@') group++;

  /* Do we want to match a host? */
  host = argv[2];

  if (host) exit(! innetgr(group, host, 0, 0));

  setnetgrent(group);
  while (getnetgrent(&hostp, &userp, &domainp)) printf("%s\n", hostp);
  endnetgrent();

  exit(0);
}