1. 命令解析
命令用途：
更新文件时间戳(访问时间aTime，修改时间mTime、状态时间)或创建不存在的文件
命令格式：
touch [OPTION]... FILE...
命令参数：
-a change only the access time
-c, --no-create do not create any files
-d, --date=STRING parse STRING and use it instead of current time
-f (ignored)
-h, --no-dereference affect each symbolic link instead of any referenced
file (useful only on systems that can change the
timestamps of a symlink)
-m change only the modification time
-r, --reference=FILE use this file's times instead of current time
-t STAMP use [[CC]YY]MMDDhhmm[.ss] instead of current time
--time=WORD change the specified time:
WORD is access, atime, or use: equivalent to -a
WORD is modify or mtime: equivalent to -m
2. 示例
2.1 更新文件时间戳(三个都改)
[root@fanshifeng touchTest]# ll
total 0
-rw-r--r-- 1 root root 0 Jan 1 12:12 f1
[root@fanshifeng touchTest]# touch f1
[root@fanshifeng touchTest]# ll
total 0
-rw-r--r-- 1 root root 0 Apr 12 19:47 f1
2.2 创建不存在的文件
root@fanshifeng touchTest]# ll
total 0
-rw-r--r-- 1 root root 0 Apr 12 19:47 f1
[root@fanshifeng touchTest]# touch f2
[root@fanshifeng touchTest]# ll
total 0
-rw-r--r-- 1 root root 0 Apr 12 19:47 f1
-rw-r--r-- 1 root root 0 Apr 12 19:48 f2
2.3 批量操作
root@fanshifeng touchTest]# ll
total 0
-rw-r--r-- 1 root root 0 Apr 12 19:47 f1
-rw-r--r-- 1 root root 0 Apr 12 19:48 f2
[root@fanshifeng touchTest]# touch f1 f2
[root@fanshifeng touchTest]# ll
total 0
-rw-r--r-- 1 root root 0 Apr 12 19:51 f1
-rw-r--r-- 1 root root 0 Apr 12 19:51 f2
2.4 只更新文件的访问时间 -a
[root@fanshifeng touchTest]# stat f1
File: `f1'
Size: 0 Blocks: 0 IO Block: 4096 regular empty file
Device: fd01h/64769d Inode: 1321195 Links: 1
Access: (0644/-rw-r--r--) Uid: ( 0/ root) Gid: ( 0/ root)
Access: 2017-04-12 19:51:22.794019631 +0800
Modify: 2017-04-12 19:51:22.794019631 +0800
Change: 2017-04-12 19:51:22.794019631 +0800
[root@fanshifeng touchTest]# touch -a f1
[root@fanshifeng touchTest]# stat f1
File: `f1'
Size: 0 Blocks: 0 IO Block: 4096 regular empty file
Device: fd01h/64769d Inode: 1321195 Links: 1
Access: (0644/-rw-r--r--) Uid: ( 0/ root) Gid: ( 0/ root)
Access: 2017-04-12 20:02:07.821548363 +0800
Modify: 2017-04-12 19:51:22.794019631 +0800
Change: 2017-04-12 20:02:07.821548363 +0800
2.5 只更新文件的修改时间 -m
[root@fanshifeng touchTest]# stat f1
File: `f1'
Size: 0 Blocks: 0 IO Block: 4096 regular empty file
Device: fd01h/64769d Inode: 1321195 Links: 1
Access: (0644/-rw-r--r--) Uid: ( 0/ root) Gid: ( 0/ root)
Access: 2017-04-12 20:02:47.304009142 +0800
Modify: 2017-04-12 20:02:47.304009142 +0800
Change: 2017-04-12 20:02:47.304009142 +0800
[root@fanshifeng touchTest]# touch -m f1
[root@fanshifeng touchTest]# stat f1
File: `f1'
Size: 0 Blocks: 0 IO Block: 4096 regular empty file
Device: fd01h/64769d Inode: 1321195 Links: 1
Access: (0644/-rw-r--r--) Uid: ( 0/ root) Gid: ( 0/ root)
Access: 2017-04-12 20:02:47.304009142 +0800
Modify: 2017-04-12 20:07:23.419261753 +0800
Change: 2017-04-12 20:07:23.419261753 +0800
2.6 不创建文件 -c
[root@fanshifeng touchTest]# ls
f1 f2
[root@fanshifeng touchTest]# touch -c f3
[root@fanshifeng touchTest]# ls
f1 f2
2.7 使用其他文件的时间戳作为当前时间戳 -r
[root@fanshifeng touchTest]# stat f2
File: `f2'
Size: 0 Blocks: 0 IO Block: 4096 regular empty file
Device: fd01h/64769d Inode: 1321198 Links: 1
Access: (0644/-rw-r--r--) Uid: ( 0/ root) Gid: ( 0/ root)
Access: 2017-04-12 19:59:57.643029077 +0800
Modify: 2017-04-12 19:51:22.794019631 +0800
Change: 2017-04-12 19:59:57.643029077 +0800
[root@fanshifeng touchTest]# touch -r f1 f2;
[root@fanshifeng touchTest]# stat f2
File: `f2'
Size: 0 Blocks: 0 IO Block: 4096 regular empty file
Device: fd01h/64769d Inode: 1321198 Links: 1
Access: (0644/-rw-r--r--) Uid: ( 0/ root) Gid: ( 0/ root)
Access: 2017-04-12 20:02:47.304009142 +0800
Modify: 2017-04-12 20:07:23.419261753 +0800
Change: 2017-04-12 20:08:58.573382677 +0800
[root@fanshifeng touchTest]# stat f1
File: `f1'
Size: 0 Blocks: 0 IO Block: 4096 regular empty file
Device: fd01h/64769d Inode: 1321195 Links: 1
Access: (0644/-rw-r--r--) Uid: ( 0/ root) Gid: ( 0/ root)
Access: 2017-04-12 20:02:47.304009142 +0800
Modify: 2017-04-12 20:07:23.419261753 +0800
Change: 2017-04-12 20:07:23.419261753 +0800
2.8 使用指定时间戳（只改变aTime和mTime）
[root@fanshifeng touchTest]# stat f1
File: `f1'
Size: 0 Blocks: 0 IO Block: 4096 regular empty file
Device: fd01h/64769d Inode: 1321195 Links: 1
Access: (0644/-rw-r--r--) Uid: ( 0/ root) Gid: ( 0/ root)
Access: 2017-04-12 20:02:47.304009142 +0800
Modify: 2017-04-12 20:07:23.419261753 +0800
Change: 2017-04-12 20:07:23.419261753 +0800
[root@fanshifeng touchTest]# touch -t201702031112.13 f1
[root@fanshifeng touchTest]# stat f1
File: `f1'
Size: 0 Blocks: 0 IO Block: 4096 regular empty file
Device: fd01h/64769d Inode: 1321195 Links: 1
Access: (0644/-rw-r--r--) Uid: ( 0/ root) Gid: ( 0/ root)
Access: 2017-02-03 11:12:13.000000000 +0800
Modify: 2017-02-03 11:12:13.000000000 +0800
Change: 2017-04-12 20:11:01.583831352 +0800
