stat实现

1.使用man 1 stat查询用法

stat命令作用：展示文件或文件夹的身份或状态

stat各项参数及功能：

• -L：显示符号链接
• -f：显示文件所在的文件系统信息
• -t：以简洁的方式输出摘要信息

stat使用实例：

• 查看文件的详细信息：stat /文件目录
• 查看文件系统的详细信息：stat -f /文件目录
• 查看简洁输出(脚本中常用来获取想要的信息)：stat -t /文件目录
• 八进制文件权限(shell脚本时会用到)：stat -c "%a" /文件目录

2.使用man -k stat | grep 2查找stat相关函数

使用man 2 stat学习函数

3.伪代码实现：
读取文件；调用函数stat；打印输出节点ino，文件类型mode，文件的连接数nlink，用户ID uid和组ID gid，块大小blksize，字节数size，块数目blocks，以及三个时间atime、mtime、ctime.
4. 产品代码 mystate.c

#include <sys/types.h>
#include <sys/stat.h>
#include <time.h>
#include <stdio.h>
#include <stdlib.h>

int main(int argc, char *argv[])
{
struct stat sb;
if (argc != 2) {
    fprintf(stderr, "Usage: %s <pathname>
", argv[0]);
    exit(EXIT_FAILURE);
}
if (stat(argv[1], &sb) == -1) {
    perror("stat");
    exit(EXIT_FAILURE);
}
printf("File type:                ");
switch (sb.st_mode & S_IFMT) {
    case S_IFBLK:   printf("block device
");
        break;
case S_IFCHR:   printf("character device
");
        break;
case S_IFDIR:   printf("directory
");
        break;
case S_IFIFO:   printf("FIFO/pipe
");
        break;
case S_IFLNK:   printf("symlink
");
        break;
case S_IFREG:   printf("regular file
");
        break;
case S_IFSOCK:  printf("socket
");
        break;
default:        printf("unknown?
");
        break;
}
printf("I-node number:            %ld
", (long) sb.st_ino);
printf("Mode:                     %lo (octal)
",(unsigned long) sb.st_mode);
printf("Link count:               %ld
", (long) sb.st_nlink);
printf("Ownership:                UID=%ld   GID=%ld
",(long) sb.st_uid, (long) sb.st_gid);
printf("Preferred I/O block size: %ld bytes
",(long) sb.st_blksize);
printf("File size:                %lld bytes
",(long long) sb.st_size);
printf("Blocks allocated:         %lld
",(long long) sb.st_blocks);
printf("Last status change:       %s", ctime(&sb.st_ctime));
printf("Last file access:         %s", ctime(&sb.st_atime));
printf("Last file modification:   %s", ctime(&sb.st_mtime));
exit(EXIT_SUCCESS);
}

5.测试代码，mystat 与stat（1）对比，提交截图