getopt1.c

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

int main(int argc, char *argv[]) {

  int c;
  while((c = getopt(argc, argv, "ab:c:")) != -1) {
    switch(c) {
      case 'a':
        printf("Flag 'a' set");
        break;
      case 'b':
        printf("Parameter b: %s\n", optarg);
        break;
      case 'c':
        printf("Parameter c: %s\n", optarg);
        break;
      default:
        abort();
    }
  }

  return EXIT_SUCCESS;
}