touch命令的作用（linux中touch命令的功能与格式）
如果创建一个新文件有很多种方法，比如:
vi filecat > fileecho "hello,world" > filetouch filetouch命令不仅可以创建新文件，而且可以修改文件的时间属性;
格式: touch [option] [file]
备注:
1) -t选项的时间格式[[CC]YY]MMDDhhmm[.ss]说明:
2) touch命令的几点说明:
１，同时创建一个或者多个空文件
linuxidc@linuxidc:~/linux/mkdir$ lslinuxidc@linuxidc:~/linux/mkdir$ touch a.txtlinuxidc@linuxidc:~/linux/mkdir$ lsa.txtlinuxidc@linuxidc:~/linux/mkdir$ touch b.txt c.txtlinuxidc@linuxidc:~/linux/mkdir$ lsa.txt b.txt c.txtlinuxidc@linuxidc:~/linux/mkdir$ touch {1..5}.txtlinuxidc@linuxidc:~/linux/mkdir$ ls1.txt 2.txt 3.txt 4.txt 5.txt a.txt b.txt c.txt2，创建文件，并用stat查看文件的属性状态信息
linuxidc@linuxidc:~/linux/mkdir$ touch linuxidc.txtlinuxidc@linuxidc:~/linux/mkdir$ stat linuxidc.txt File: 'linuxidc.txt' Size: 0 Blocks: 0 IO Block: 4096 regular empty filelinuxidcice: 807h/2055d Inode: 9569451 Links: 1Access: (0664/-rw-rw-r--) Uid: ( 1000/ linuxidc) Gid: ( 1000/ linuxidc)Access: 2018-05-01 17:25:16.439856937 0800Modify: 2018-05-01 17:25:16.439856937 0800Change: 2018-05-01 17:25:16.439856937 0800 Birth: -最后有３个时间Access time: 最后访问时间，查看文件的内容时，这个时间会改变，使用cat命令查看文件时，可以看出Access time已经变了linuxidc@linuxidc:~/linux/mkdir$ stat linuxidc.txt File: 'linuxidc.txt' Size: 0 Blocks: 0 IO Block: 4096 regular empty filelinuxidcice: 807h/2055d Inode: 9569451 Links: 1Access: (0664/-rw-rw-r--) Uid: ( 1000/ linuxidc) Gid: ( 1000/ linuxidc)Access: 2018-05-01 17:25:16.439856937 0800Modify: 2018-05-01 17:25:16.439856937 0800Change: 2018-05-01 17:25:16.439856937 0800 Birth: -linuxidc@linuxidc:~/linux/mkdir$ cat linuxidc.txt linuxidc@linuxidc:~/linux/mkdir$ stat linuxidc.txt File: 'linuxidc.txt' Size: 0 Blocks: 0 IO Block: 4096 regular empty filelinuxidcice: 807h/2055d Inode: 9569451 Links: 1Access: (0664/-rw-rw-r--) Uid: ( 1000/ linuxidc) Gid: ( 1000/ linuxidc)Access: 2018-05-01 17:27:51.887215139 0800Modify: 2018-05-01 17:25:16.439856937 0800Change: 2018-05-01 17:25:16.439856937 0800 Birth: -Modify time:最后修改时间，修改文件内容，文件的修改时间会改变。访问时间和状态改变时间 也发生变化linuxidc@linuxidc:~/linux/mkdir$ stat linuxidc.txt File: 'linuxidc.txt' Size: 0 Blocks: 0 IO Block: 4096 regular empty filelinuxidcice: 807h/2055d Inode: 9569451 Links: 1Access: (0664/-rw-rw-r--) Uid: ( 1000/ linuxidc) Gid: ( 1000/ linuxidc)Access: 2018-05-01 17:27:51.887215139 0800Modify: 2018-05-01 17:25:16.439856937 0800Change: 2018-05-01 17:25:16.439856937 0800 Birth: -linuxidc@linuxidc:~/linux/mkdir$ vim linuxidc.txt linuxidc@linuxidc:~/linux/mkdir$ stat linuxidc.txt File: 'linuxidc.txt' Size: 5 Blocks: 8 IO Block: 4096 regular filelinuxidcice: 807h/2055d Inode: 9569550 Links: 1Access: (0664/-rw-rw-r--) Uid: ( 1000/ linuxidc) Gid: ( 1000/ linuxidc)Access: 2018-05-01 17:29:34.982228802 0800Modify: 2018-05-01 17:29:34.982228802 0800Change: 2018-05-01 17:29:35.018231392 0800 Birth: -Change time:状态改变时间,修改文件内容，移动文件，或者改变文件属性等，文件的change time会发生改变.１，移动文件( 重命名 ), change time 发生改变:linuxidc@linuxidc:~/linux/mkdir$ stat linuxidc.txt File: 'linuxidc.txt' Size: 5 Blocks: 8 IO Block: 4096 regular filelinuxidcice: 807h/2055d Inode: 9569550 Links: 1Access: (0664/-rw-rw-r--) Uid: ( 1000/ linuxidc) Gid: ( 1000/ linuxidc)Access: 2018-05-01 17:29:34.982228802 0800Modify: 2018-05-01 17:29:34.982228802 0800Change: 2018-05-01 17:29:35.018231392 0800 Birth: -linuxidc@linuxidc:~/linux/mkdir$ mv linuxidc.txt linuxidc2.txtlinuxidc@linuxidc:~/linux/mkdir$ stat linuxidc2.txt File: 'linuxidc2.txt' Size: 5 Blocks: 8 IO Block: 4096 regular filelinuxidcice: 807h/2055d Inode: 9569550 Links: 1Access: (0664/-rw-rw-r--) Uid: ( 1000/ linuxidc) Gid: ( 1000/ linuxidc)Access: 2018-05-01 17:29:34.982228802 0800Modify: 2018-05-01 17:29:34.982228802 0800Change: 2018-05-01 17:32:25.392863791 0800
2，修改文件的权限，change time发生了改变
linuxidc@linuxidc:~/linux/mkdir$ stat linuxidc2.txt File: 'linuxidc2.txt' Size: 5 Blocks: 8 IO Block: 4096 regular filelinuxidcice: 807h/2055d Inode: 9569550 Links: 1Access: (0664/-rw-rw-r--) Uid: ( 1000/ linuxidc) Gid: ( 1000/ linuxidc)Access: 2018-05-01 17:29:34.982228802 0800Modify: 2018-05-01 17:29:34.982228802 0800Change: 2018-05-01 17:32:25.392863791 0800 Birth: -linuxidc@linuxidc:~/linux/mkdir$ chmod 777 linuxidc2.txt linuxidc@linuxidc:~/linux/mkdir$ stat linuxidc2.txt File: 'linuxidc2.txt' Size: 5 Blocks: 8 IO Block: 4096 regular filelinuxidcice: 807h/2055d Inode: 9569550 Links: 1Access: (0777/-rwxrwxrwx) Uid: ( 1000/ linuxidc) Gid: ( 1000/ linuxidc)Access: 2018-05-01 17:29:34.982228802 0800Modify: 2018-05-01 17:29:34.982228802 0800Change: 2018-05-01 17:33:31.602584110 0800 Birth: -touch -m修改文件的modify和change时间linuxidc@linuxidc:~/linux/mkdir$ stat linuxidc2.txt File: 'linuxidc2.txt' Size: 5 Blocks: 8 IO Block: 4096 regular filelinuxidcice: 807h/2055d Inode: 9569550 Links: 1Access: (0777/-rwxrwxrwx) Uid: ( 1000/ linuxidc) Gid: ( 1000/ linuxidc)Access: 2018-05-01 17:29:34.982228802 0800Modify: 2018-05-01 17:29:34.982228802 0800Change: 2018-05-01 17:33:31.602584110 0800 Birth: -linuxidc@linuxidc:~/linux/mkdir$ touch -m linuxidc2.txt linuxidc@linuxidc:~/linux/mkdir$ stat linuxidc2.txt File: 'linuxidc2.txt' Size: 5 Blocks: 8 IO Block: 4096 regular filelinuxidcice: 807h/2055d Inode: 9569550 Links: 1Access: (0777/-rwxrwxrwx) Uid: ( 1000/ linuxidc) Gid: ( 1000/ linuxidc)Access: 2018-05-01 17:29:34.982228802 0800Modify: 2018-05-01 17:34:31.678864985 0800Change: 2018-05-01 17:34:31.678864985 0800touch -d修改创建后的文件的修改时间linuxidc@linuxidc:~/linux/mkdir$ ls -lh linuxidc2.txt -rwxrwxrwx 1 linuxidc linuxidc 5 5月 1 17:34 linuxidc2.txtlinuxidc@linuxidc:~/linux/mkdir$ touch -d 20190218 linuxidc2.txt linuxidc@linuxidc:~/linux/mkdir$ ls -lh linuxidc2.txt -rwxrwxrwx 1 linuxidc linuxidc 5 2月 18 2019 linuxidc2.txtlinuxidc@linuxidc:~/linux/mkdir$ stat linuxidc2.txt File: 'linuxidc2.txt' Size: 5 Blocks: 8 IO Block: 4096 regular filelinuxidcice: 807h/2055d Inode: 9569550 Links: 1Access: (0777/-rwxrwxrwx) Uid: ( 1000/ linuxidc) Gid: ( 1000/ linuxidc)Access: 2019-02-18 00:00:00.000000000 0800Modify: 2019-02-18 00:00:00.000000000 0800Change: 2018-05-01 17:37:13.031347481 0800 Birth: -
