shell date 获取昨天日期

[root@localhost riqi]# date +'%Y-%m-%d %H:%M:%S'

2012-07-18 05:17:01

[root@localhost riqi]# date +'%Y-%m-%d %H:%M:%S' -d '+10hour'

2012-07-18 15:17:16

[root@localhost riqi]# date +'%Y-%m-%d %H:%M:%S' -d '+24hour'

2012-07-19 05:17:37

[root@localhost riqi]# date +'%Y-%m-%d %H:%M:%S' -d '-24hour'

2012-07-17 05:17:45

[root@localhost riqi]# date +'%Y-%m-%d %H:%M:%S' -d '-20minute'

2012-07-18 04:58:00

[root@localhost riqi]# date +'%Y-%m-%d %H:%M:%S' -d '+20minute'

2012-07-18 05:38:05

[root@localhost riqi]# date +'%Y-%m-%d %H:%M:%S' -d '+2day'

2012-07-20 05:18:15

[root@localhost riqi]# date +'%Y-%m-%d %H:%M:%S' -d '-2day'

2012-07-16 05:18:19

[root@localhost riqi]# date +'%Y-%m-%d %H:%M:%S' -d '-2month'

2012-05-18 05:18:24

[root@localhost riqi]# date +'%Y-%m-%d %H:%M:%S' -d '+2month'

2012-09-18 05:18:28

[root@localhost riqi]# date +'%Y-%m-%d %H:%M:%S' -d '+2year'

2014-07-18 05:18:32

[root@localhost riqi]# date +'%Y-%m-%d %H:%M:%S' -d '-2year'

2010-07-18 05:18:36