date #显示系统当前的时间。
![date时间](https://s1.51cto.com/images/blog/201812/28/25282fb0de5bb34573648cd5bbb42669.png?x-oss-process=image/watermark,size_16,text_QDUxQ1RP5Y2a5a6i,color_FFFFFF,t_100,g_se,x_10,y_10,shadow_90,type_ZmFuZ3poZW5naGVpdGk=)
date +%Y #查看当前年份(4位)
![date时间](https://s1.51cto.com/images/blog/201812/28/b435bb7cb9b1f2617ffb263b908fe10f.png?x-oss-process=image/watermark,size_16,text_QDUxQ1RP5Y2a5a6i,color_FFFFFF,t_100,g_se,x_10,y_10,shadow_90,type_ZmFuZ3poZW5naGVpdGk=)
date +%y #显示2位的年份
![date时间](https://s1.51cto.com/images/blog/201812/28/043fc80c1cd839b959623c81c30c4e90.png?x-oss-process=image/watermark,size_16,text_QDUxQ1RP5Y2a5a6i,color_FFFFFF,t_100,g_se,x_10,y_10,shadow_90,type_ZmFuZ3poZW5naGVpdGk=)
date +%m #显示当前的年份
![date时间](https://s1.51cto.com/images/blog/201812/28/fbdb1fa75495de4fffb88bf22eb496e0.png?x-oss-process=image/watermark,size_16,text_QDUxQ1RP5Y2a5a6i,color_FFFFFF,t_100,g_se,x_10,y_10,shadow_90,type_ZmFuZ3poZW5naGVpdGk=)
date +%M #显示当前的分钟
![date时间](https://s1.51cto.com/images/blog/201812/28/ad2cdb07fe4939421f488dc8a89ea7cb.png?x-oss-process=image/watermark,size_16,text_QDUxQ1RP5Y2a5a6i,color_FFFFFF,t_100,g_se,x_10,y_10,shadow_90,type_ZmFuZ3poZW5naGVpdGk=)
date +%d #日期
![date时间](https://s1.51cto.com/images/blog/201812/28/fcd36092394497e034719b303834ff63.png?x-oss-process=image/watermark,size_16,text_QDUxQ1RP5Y2a5a6i,color_FFFFFF,t_100,g_se,x_10,y_10,shadow_90,type_ZmFuZ3poZW5naGVpdGk=)
date +%D #显示年月日,格式有点特殊,显示日/月/年
![date时间](https://s1.51cto.com/images/blog/201812/28/caf67f69b240d1e474cbd07eceaad5c2.png?x-oss-process=image/watermark,size_16,text_QDUxQ1RP5Y2a5a6i,color_FFFFFF,t_100,g_se,x_10,y_10,shadow_90,type_ZmFuZ3poZW5naGVpdGk=)
date +%Y%m%d #显示年月日
![date时间](https://s1.51cto.com/images/blog/201812/28/302783907f8c2b4d87e1bf6abf963f8f.png?x-oss-process=image/watermark,size_16,text_QDUxQ1RP5Y2a5a6i,color_FFFFFF,t_100,g_se,x_10,y_10,shadow_90,type_ZmFuZ3poZW5naGVpdGk=)
当前时间 date +%T
![date时间](https://s1.51cto.com/images/blog/201812/28/7b429ffb70503948d69afd7d5bbfe0aa.png?x-oss-process=image/watermark,size_16,text_QDUxQ1RP5Y2a5a6i,color_FFFFFF,t_100,g_se,x_10,y_10,shadow_90,type_ZmFuZ3poZW5naGVpdGk=)
date +%F #当前日期,格式带-
![date时间](https://s1.51cto.com/images/blog/201812/28/149bd6c4674788c10f65e5d84c95e501.png?x-oss-process=image/watermark,size_16,text_QDUxQ1RP5Y2a5a6i,color_FFFFFF,t_100,g_se,x_10,y_10,shadow_90,type_ZmFuZ3poZW5naGVpdGk=)
date +%H #显示时
![date时间](https://s1.51cto.com/images/blog/201812/28/c47452124a76bbddcf40a0a41e1aecf0.png?x-oss-process=image/watermark,size_16,text_QDUxQ1RP5Y2a5a6i,color_FFFFFF,t_100,g_se,x_10,y_10,shadow_90,type_ZmFuZ3poZW5naGVpdGk=)
date +%s #时间戳,距离1970年1月1日零点零分,到现在过去多少秒
![date时间](https://s1.51cto.com/images/blog/201812/28/1999c81264446a7e9797e8a2b509faef.png?x-oss-process=image/watermark,size_16,text_QDUxQ1RP5Y2a5a6i,color_FFFFFF,t_100,g_se,x_10,y_10,shadow_90,type_ZmFuZ3poZW5naGVpdGk=)
date +%S #秒
![date时间](https://s1.51cto.com/images/blog/201812/28/2f3bda47477ebc6d3f98eb40e67e8292.png?x-oss-process=image/watermark,size_16,text_QDUxQ1RP5Y2a5a6i,color_FFFFFF,t_100,g_se,x_10,y_10,shadow_90,type_ZmFuZ3poZW5naGVpdGk=)
当前日期通常表达式 date +%Y%m%d
![date时间](https://s1.51cto.com/images/blog/201812/28/c58fc3ac8b2b7e2cc8b670f232f0b5cd.png?x-oss-process=image/watermark,size_16,text_QDUxQ1RP5Y2a5a6i,color_FFFFFF,t_100,g_se,x_10,y_10,shadow_90,type_ZmFuZ3poZW5naGVpdGk=)
当前周几 date +%w
![date时间](https://s1.51cto.com/images/blog/201812/28/434bce3645d409d5f1716be2dbdafee5.png?x-oss-process=image/watermark,size_16,text_QDUxQ1RP5Y2a5a6i,color_FFFFFF,t_100,g_se,x_10,y_10,shadow_90,type_ZmFuZ3poZW5naGVpdGk=)
本年度第几周? date +%W
![date时间](https://s1.51cto.com/images/blog/201812/28/6c276217279525a883d5bdb6781c3bc2.png?x-oss-process=image/watermark,size_16,text_QDUxQ1RP5Y2a5a6i,color_FFFFFF,t_100,g_se,x_10,y_10,shadow_90,type_ZmFuZ3poZW5naGVpdGk=)
cal #显示日历
![date时间](https://s1.51cto.com/images/blog/201812/28/ed871d814fb6603d02fc7a6bc127033b.png?x-oss-process=image/watermark,size_16,text_QDUxQ1RP5Y2a5a6i,color_FFFFFF,t_100,g_se,x_10,y_10,shadow_90,type_ZmFuZ3poZW5naGVpdGk=)
备份数据库:
msyqldump -uroot -p密码 database >4.sql
![date时间](https://s1.51cto.com/images/blog/201812/28/392fddca0575c3caeb3492f3ec88040d.png?x-oss-process=image/watermark,size_16,text_QDUxQ1RP5Y2a5a6i,color_FFFFFF,t_100,g_se,x_10,y_10,shadow_90,type_ZmFuZ3poZW5naGVpdGk=)
如果到下周四,会覆盖上周四,会一直保持保留一周的数据
date -d "-1 day" +%F #当前的日期减去1天。
![date时间](https://s1.51cto.com/images/blog/201812/28/2ec5269d840b0324f445b041b8b27262.png?x-oss-process=image/watermark,size_16,text_QDUxQ1RP5Y2a5a6i,color_FFFFFF,t_100,g_se,x_10,y_10,shadow_90,type_ZmFuZ3poZW5naGVpdGk=)
date -d "-1 month" +%F #当前的月份减去1月,就是上个月
![date时间](https://s1.51cto.com/images/blog/201812/28/917d908342599d3eb20d91a86f6a4787.png?x-oss-process=image/watermark,size_16,text_QDUxQ1RP5Y2a5a6i,color_FFFFFF,t_100,g_se,x_10,y_10,shadow_90,type_ZmFuZ3poZW5naGVpdGk=)
date -d "-1 year" +%F #去年
date -d "+1day" 一天后
date -d "-1 min" 一分钟前
当前的日期,换算成时间戳
![date时间](https://s1.51cto.com/images/blog/201812/28/5311f619728e9f67d51a15b9eed66b07.png?x-oss-process=image/watermark,size_16,text_QDUxQ1RP5Y2a5a6i,color_FFFFFF,t_100,g_se,x_10,y_10,shadow_90,type_ZmFuZ3poZW5naGVpdGk=)