Three times in Linux

Source: Internet
Author: User

Mtime:modify Time modification time, change the content of the file will be modified.

Ctime:change time State modification times, change owner and permission, file name, size, inode number

Atime:access Time Access

    1. How do I view a file for three times?

Stat filename

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2. How do I use these three times?

There are a lot of parameters in find, and there's something about this.

-mmin N

File ' s data was last modified N minutes ago. #文件的数据最后修改了N分钟前.

-cmin N

File ' s status is last changed N minutes ago. #档案的状态最后改变了N分钟前.

-amin N

File was last accessed N minutes ago. #N分钟前访问了文件.

So how do I see the files I modified one hours ago?



3. Do you have an issue with access time unchanged?

I read the corresponding file with cat filename and found that access time was not refreshed.

And to modify the contents of the file, found that the access time has been refreshed

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Official explanation:

Prior to kernel version 2.6.30, core Linux developers discussed the performance of EXT3/EXT4 file systems, including Atime. Before kernel 2.6.30, the atime is updated in a timely manner by default in the file system, which brings two issues:

(1) A large number of file access in the system, writes atime to disk, consumes time, thereby reducing performance

(2) This operation also consumes electricity.

Running on Linux, few applications need to get accurate atime time, and Linux core developers from the Ext3/ext4 file system performance perspective, Decide to modify the Atime Update method in the 2.6.30 Kernel and update atime only in one of the following three scenarios:

(1) If the partition mount is specified in a non-relatime mode (by default, Relatime mode), such as Strictatime.

Add: When the OS starts, the partitions are mounted to different directories, and Strictatime is used in the mount parameter to indicate that the atime is updated in a timely manner. After 2.6.30, Mount added "Relatime" and "Strictatime" two options, which can be viewed in detail by "Man Mount".

(2) When the atime is less than ctime or less than mtime

(3) This access time and last atime more than 24 hours

This article is from the "Flying Small GUI" blog, make sure to keep this source

Three times in Linux

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