写脚本经常会用到的一些时间格式

date +%F' '%T
date +%D
04/09/20
date +%F
2020-04-09
date +%x
04/09/2020
date +%T
17:12:04
date +%X
05:13:38 PM
date +%r
05:17:17 PM
date +%R
17:17
date +%w
4
date +%u
4
date +%W
14
date +%U
14
date +%j
100
cal -j
date +%s
1586423885
date -d @1570885555 +%F-%T
2019-10-12-21:05:55
date -d 'yesterday'
Wed Apr  8 17:22:03 CST 2020
date -d 'yesterday' +%Y%m%d
20200408
date -d '5 days ago 3 hours 20minutes' +%Y%m%d-%H:%M:%S
20200404-20:43:42
date -d '5 days ago 3 hours 20minutes ago' +%Y%m%d-%H:%M:%S   #没有ago,默认就是以后
20200404-20:03:59
date -d '5days ago 3hours ago 20minutes ago' +%Y%m%d-%H:%M:%S   #数字与时间单位之间可以不要空格
20200404-14:04:27
date -d '1 year ago 2 weeks tomorrow 3 hours ago 4 minutes 5 seconds ago'   #一年前2周后明天3小时前4分后5秒前
Wed Apr 24 14:42:45 CST 2019
date +%Y%m01  #本月第一天 
date -d "`date +%Y%m01` last day" +%Y%m%d   #上个月最后一天,1个单位前可以用last,多个用 n单位 ago
date -d "`date +%Y%m01` last month" +%Y%m%d   #上个月第一天
date -d "`date +%Y%m01` last year last month last day" +%Y%m%d   #去年上个月1号的前一天（去年上上个月最后一天）

FORMAT controls the output.  Interpreted sequences are:

  %%   a literal %
  %a   locale's abbreviated weekday name (e.g., Sun)
  %A   locale's full weekday name (e.g., Sunday)
  %b   locale's abbreviated month name (e.g., Jan)
  %B   locale's full month name (e.g., January)
  %c   locale's date and time (e.g., Thu Mar  3 23:05:25 2005)
  %C   century; like %Y, except omit last two digits (e.g., 20)
  %d   day of month (e.g., 01)
  %D   date; same as %m/%d/%y
  %e   day of month, space padded; same as %_d
  %F   full date; same as %Y-%m-%d
  %g   last two digits of year of ISO week number (see %G)
  %G   year of ISO week number (see %V); normally useful only with %V
  %h   same as %b
  %H   hour (00..23)
  %I   hour (01..12)
  %j   day of year (001..366)
  %k   hour, space padded ( 0..23); same as %_H
  %l   hour, space padded ( 1..12); same as %_I
  %m   month (01..12)
  %M   minute (00..59)
  %n   a newline
  %N   nanoseconds (000000000..999999999)
  %p   locale's equivalent of either AM or PM; blank if not known
  %P   like %p, but lower case
  %r   locale's 12-hour clock time (e.g., 11:11:04 PM)
  %R   24-hour hour and minute; same as %H:%M
  %s   seconds since 1970-01-01 00:00:00 UTC
  %S   second (00..60)
  %t   a tab
  %T   time; same as %H:%M:%S
  %u   day of week (1..7); 1 is Monday
  %U   week number of year, with Sunday as first day of week (00..53)
  %V   ISO week number, with Monday as first day of week (01..53)
  %w   day of week (0..6); 0 is Sunday
  %W   week number of year, with Monday as first day of week (00..53)
  %x   locale's date representation (e.g., 12/31/99)
  %X   locale's time representation (e.g., 23:13:48)
  %y   last two digits of year (00..99)
  %Y   year
  %z   +hhmm numeric time zone (e.g., -0400)
  %:z  +hh:mm numeric time zone (e.g., -04:00)
  %::z  +hh:mm:ss numeric time zone (e.g., -04:00:00)
  %:::z  numeric time zone with : to necessary precision (e.g., -04, +05:30)
  %Z   alphabetic time zone abbreviation (e.g., EDT)