Create a file "1 week ago"
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#root@ubun1204:/root/study# date +%Y%m%d
20140718
root@ubun1204:/root/study# touch -d "1 week ago" file2
root@ubun1204:/root/study# touch -d "10 day ago" file1
root@ubun1204:/root/study# ls -l file1 file2
-rw-r--r-- 1 root root 0 Jul 8 23:10 file1
-rw-r--r-- 1 root root 0 Jul 11 23:10 file2
Create a file which date is several days ago
原文：http://9181221.blog.51cto.com/9171221/1440092