linux date命令

 man date:

DATE(1)                          User Commands                         DATE(1)



NAME
       date - print or set the system date and time

SYNOPSIS
       date [OPTION]... [+FORMAT]
       date [-u|--utc|--universal] [MMDDhhmm[[CC]YY][.ss]]

DESCRIPTION
       Display the current time in the given FORMAT, or set the system date.

       -d, --date=STRING
              display time described by STRING, not `now'

       -f, --file=DATEFILE
              like --date once for each line of DATEFILE

       -r, --reference=FILE
              display the last modification time of FILE

       -R, --rfc-2822
              output  date  and time in RFC 2822 format.  Example: Mon, 07 Aug
              2006 12:34:56 -0600

       --rfc-3339=TIMESPEC
              output date and time in RFC 3339 format.  TIMESPEC=`date', `sec‐
              onds',  or  `ns'  for  date and time to the indicated precision.
              Date and time  components  are  separated  by  a  single  space:
              2006-08-07 12:34:56-06:00

       -s, --set=STRING
              set time described by STRING

       -u, --utc, --universal
              print or set Coordinated Universal Time

       --help display this help and exit

       --version
              output version information and exit

       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)

       By default, date  pads  numeric  fields  with  zeroes.   The  following
       optional flags may follow `%':

       -      (hyphen) do not pad the field

       _      (underscore) pad with spaces

       0      (zero) pad with zeros

       ^      use upper case if possible

       #      use opposite case if possible

       After  any  flags  comes  an optional field width, as a decimal number;
       then an optional modifier, which is either E to use the locale's alter‐
       nate  representations  if available, or O to use the locale's alternate
       numeric symbols if available.

EXAMPLES
       Convert seconds since the epoch (1970-01-01 UTC) to a date

              $ date --date='@2147483647'

       Show the time on the west coast of the US (use tzselect(1) to find TZ)

              $ TZ='America/Los_Angeles' date

       Show the local time for 9AM next Friday on the west coast of the US

              $ date --date='TZ="America/Los_Angeles" 09:00 next Fri'

DATE STRING
       The --date=STRING is a mostly free format human  readable  date  string
       such  as  "Sun, 29 Feb 2004 16:21:42 -0800" or "2004-02-29 16:21:42" or
       even "next Thursday".  A date string may contain items indicating  cal‐
       endar  date,  time of day, time zone, day of week, relative time, rela‐
       tive date, and numbers.  An empty string indicates the beginning of the
       day.   The date string format is more complex than is easily documented
       here but is fully described in the info documentation.

 

加减
date +%Y%m%d         //显示现在天年月日
date +%Y%m%d --date="+1 day"  //显示后一天的日期
date +%Y%m%d --date="-1 day"  //显示前一天的日期
date +%Y%m%d --date="-1 month"  //显示上一月的日期
date +%Y%m%d --date="+1 month"  //显示下一月的日期
date +%Y%m%d --date="-1 year"  //显示前一年的日期
date +%Y%m%d --date="+1 year"  //显示下一年的日期

或者更简单点的  date=`date -d -${t}day '+%Y%m%d'` //为t为前几天