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

main()
{
	int pid;

	switch (pid = fork()) {
	case -1:
		perror("fork error");
		exit(1);
		break;
	case 0:
		execl("/bin/ls", "ls", NULL);
		break;
	default:
		wait();
		printf("parent process\n");
		break;
	}

	exit(0);
}