4.5.4 Timestamps

There are three types of timestamps for a GNU/Linux file:

• mtime: the modification time (ls -l),

• ctime: the status change time (ls -lc), and

• atime: the last access time (ls -lu).

Note that ctime is not file creation time.

• Overwriting a file will change all of mtime, ctime, and atime of the file.

• Changing permission or owner of a file will change ctime and atime of the file.

• Reading a file will change atime of the file.

Note that even simply reading a file on the Debian system will normally cause a file write operation to update atime information in the inode. Mounting a filesystem with the noatime option will let the system skip this operation and will result in faster file access for the read. See mount(8).

Use touch(1) command to change timestamps of existing files.