文件管理命令：stat

1、文件由元数据和数据组成，其中元数据包括访问时间、更新时间、修改时间、创建时间等

2、stat:display file or file system status

        stat [OPTION]... FILE...

>>stat /tmp/

  File: ‘/tmp/’

  Size: 4096            Blocks: 8          IO Block: 4096  directory

Device: fd00h/64768d    Inode: 134294600  Links: 18

Access: (1777/drwxrwxrwt)  Uid: (    0/    root)  Gid: (    0/    root)

Access: 2018-08-22 10:10:55.071954516 +0000

Modify: 2018-08-22 10:10:55.073954524 +0000

Change: 2018-08-22 10:10:55.073954524 +0000

Birth: -

3、修改文件时间戳

touch: change file timestamps

touch [OPTION]... FILE...

-a    change only the access time

-c, --no-create , do not create any files  ##修改（access,modify time）时间戳；文件不存在时也不创建文件

-m    change only the modification time

-t STAMP ,use [[CC]YY]MMDDhhmm[.ss] instead of current time

示例：

>> touch file1  #修改文件时间戳，如果目标文件不存在，则创建

>> stat file1

  File: ‘file1’

  Size: 0              Blocks: 0          IO Block: 4096  regular empty file

Device: fd00h/64768d    Inode: 135598097  Links: 1

Access: (0664/-rw-rw-r--)  Uid: (56007/ vn0eco6)  Gid: (56007/ vn0eco6)

Access: 2018-08-21 02:57:56.180571683 +0000

Modify: 2018-08-21 02:57:56.180571683 +0000

Change: 2018-08-21 02:57:56.180571683 +0000

Birth: -

>>touch -m file1   #修改modify time为当前时间

>>touch -t 201808081010.30 file1 #为modify time设置指定时间戳,change time 会随之而变