/* jerry.c v2.0 */#include <unistd.h>#include <sys/types.h>#include <sys/stat.h>#include <sys/wait.h>#include <fcntl.h>#include <stdlib.h>#include <stdio.h>#define FILE "message.txt"#define CHILD_MSG "I am Mickey.\n"#define FATHER_MSG "I am Jerry.\n"int main(){  int fd;  char buf[BUFSIZ];  ssize_t s;  /* Open file for read. */  fd = open(FILE, O_RDONLY, 0666);  if(fd < 0) {    perror("open");  }  /* Read message. */  do {    s = read(fd, &buf, BUFSIZ);    write(STDOUT_FILENO, &buf, s);  } while (s>0);  /* Close file. */  close(fd);  if(fork() == 0) {    write(STDOUT_FILENO, CHILD_MSG, sizeof(CHILD_MSG)-1);  } else {    wait(NULL); 		/* wait for any child exit. */    write(STDOUT_FILENO, FATHER_MSG, sizeof(FATHER_MSG)-1);  }    exit(EXIT_SUCCESS);}