SO #6

#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <unistd.h>
#include <sys/wait.h>

int main(int argc, char *args[]) {
  if(argc < 3) {
    fprintf(stderr, "Usage: %s <number> <file1> <file2> ...\n", args[0]);
    exit(1);
  }

  int pid;
  int i = 0;

  if((pid=fork()) < 0)
  {
    perror("ERROR");
    exit(1);
  }
  if(pid==0)
  {
      for(i = 0; i <= atoi(args[1]); i++) {
	printf("%d: %d\n", getpid(), i);
      }
      exit(0);
  }
  for(i = 2; i <= argc-1; i++) {
    if((pid=fork()) < 0)
    {
      perror("ERROR");
      exit(1);
    }
    if(pid==0)
    {
      char *argv[] = { "wc", args[i], "-l", 0 };
      execvp(argv[0], argv);
    } else {
      int status;
      wait(&status);
      if (WIFEXITED(status)) {
	printf("PID: %d exited, status=%d\n", pid, WEXITSTATUS(status));
      } else if (WIFSIGNALED(status)) {
	printf("PID: %d killed by signal %d\n", pid, WTERMSIG(status));
      } else if (WIFSTOPPED(status)) {
	printf("PID: %d stopped by signal %d\n", pid, WSTOPSIG(status));
      } else if (WIFCONTINUED(status)) {
	printf("PID: %d continued\n", pid);
      }
    }
  }

  return 1;
}