date用法1:

       格式：date [OPTION]... [+FORMAT]

       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

例如：

1.年月日

$ date +%Y%m%d
20150107

~$ date +%y%m%d
150107

3.小时分钟秒

~$ date +%H%M%S
233045

~$ date +%Y%m%d%H%M%S
20150107233145

待续……

linux命令之date