在项目过程中要删除一些过期文件，但是到期了，有些文件居然没有被删除。后来发现，原来在转移文件的时候使用的mv命令会影响文件的Change Time,造成文件没有被认定为超时。为了避免类似问题发生，做了个简单的实验，结果如下：值得注意的是从结果看中可以看出当文件被下载时，Access Time也会改变。
touch Access Modify Change
echo - Modify Change
vim Access Modify Change
cat Access - -
mv - - Change
stat - - -
nginx Access - -
过程如下：
[root@localhost teststat]# touch aaa.tmp [root@localhost teststat]# stat aaa.tmp File: `aaa.tmp‘ Size: 0 Blocks: 0 IO Block: 4096 regular empty file Device: fd00h/64768d Inode: 22380566 Links: 1 Access: (0644/-rw-r--r--) Uid: ( 0/ root) Gid: ( 0/ root) Access: 2016-02-01 09:18:57.000000000 +0800 Modify: 2016-02-01 09:18:57.000000000 +0800 Change: 2016-02-01 09:18:57.000000000 +0800 [root@localhost teststat]# echo "help">aaa.tmp [root@localhost teststat]# stat aaa.tmp File: `aaa.tmp‘ Size: 5 Blocks: 8 IO Block: 4096 regular file Device: fd00h/64768d Inode: 22380566 Links: 1 Access: (0644/-rw-r--r--) Uid: ( 0/ root) Gid: ( 0/ root) Access: 2016-02-01 09:18:57.000000000 +0800 Modify: 2016-02-01 09:19:21.000000000 +0800 Change: 2016-02-01 09:19:21.000000000 +0800 [root@localhost teststat]# vim aaa.tmp [root@localhost teststat]# stat aaa.tmp File: `aaa.tmp‘ Size: 13 Blocks: 8 IO Block: 4096 regular file Device: fd00h/64768d Inode: 22380568 Links: 1 Access: (0644/-rw-r--r--) Uid: ( 0/ root) Gid: ( 0/ root) Access: 2016-02-01 09:20:51.000000000 +0800 Modify: 2016-02-01 09:20:51.000000000 +0800 Change: 2016-02-01 09:20:51.000000000 +0800 [root@localhost teststat]# echo "echo re">>aaa.tmp [root@localhost teststat]# stat aaa.tmp File: `aaa.tmp‘ Size: 21 Blocks: 8 IO Block: 4096 regular file Device: fd00h/64768d Inode: 22380568 Links: 1 Access: (0644/-rw-r--r--) Uid: ( 0/ root) Gid: ( 0/ root) Access: 2016-02-01 09:20:51.000000000 +0800 Modify: 2016-02-01 09:21:20.000000000 +0800 Change: 2016-02-01 09:21:20.000000000 +0800 [root@localhost teststat]# cat aaa.tmp hello world! echo re [root@localhost teststat]# stat aaa.tmp File: `aaa.tmp‘ Size: 21 Blocks: 8 IO Block: 4096 regular file Device: fd00h/64768d Inode: 22380568 Links: 1 Access: (0644/-rw-r--r--) Uid: ( 0/ root) Gid: ( 0/ root) Access: 2016-02-01 09:22:05.000000000 +0800 Modify: 2016-02-01 09:21:20.000000000 +0800 Change: 2016-02-01 09:21:20.000000000 +0800 [root@localhost teststat]# mv aaa.tmp bbb.tmp [root@localhost teststat]# stat bbb.tmp File: `bbb.tmp‘ Size: 21 Blocks: 8 IO Block: 4096 regular file Device: fd00h/64768d Inode: 22380568 Links: 1 Access: (0644/-rw-r--r--) Uid: ( 0/ root) Gid: ( 0/ root) Access: 2016-02-01 09:22:05.000000000 +0800 Modify: 2016-02-01 09:21:20.000000000 +0800 Change: 2016-02-01 09:22:28.000000000 +0800 然后用nginx下载文件，再次查看文件状态 [root@localhost teststat]# stat bbb.tmp File: `bbb.tmp‘ Size: 21 Blocks: 8 IO Block: 4096 regular file Device: fd00h/64768d Inode: 22380568 Links: 1 Access: (0644/-rw-r--r--) Uid: ( 0/ root) Gid: ( 0/ root) Access: 2016-02-01 09:42:05.000000000 +0800 Modify: 2016-02-01 09:21:20.000000000 +0800 Change: 2016-02-01 09:22:28.000000000 +0800
原文：http://www.cnblogs.com/bugutian/p/5175057.html