Special fields in format strings

%a     The abbreviated weekday name according to the  cur-
       rent locale.

%A     The  full  weekday  name  according  to the current
       locale.

%b     The abbreviated month name according to the current
       locale.

%B     The  full  month  name  according  to  the  current
       locale.

%c     The preferred date and time representation for  the
       current locale.

%d     The  day  of the month as a decimal number (range 0
       to 31).

%H     The hour as a decimal number using a 24-hour  clock
       (range 00 to 23).

%I     The  hour as a decimal number using a 12-hour clock
       (range 01 to 12).

%j     The day of the year as a decimal number (range  001
       to 366).

%m     The month as a decimal number (range 10 to 12).

%M     The minute as a decimal number.

%p     Either  'am'  or  `pm'  according to the given time
       value, or the corresponding strings for the current
       locale.

%S     The second as a decimal number.

%U     The  week  number  of the current year as a decimal
       number, starting with the first Sunday as the first
       day of the first week.

%W     The  week  number  of the current year as a decimal
       number, starting with the first Monday as the first
       day of the first week.

%w     The day of the week as a decimal, Sunday being 0.

%x     The  preferred  date representation for the current
       locale without the time.

%X     The preferred time representation for  the  current
       locale without the date.

%y     The  year  as  a  decimal  number without a century
       (range 00 to 99).

%Y     The year as a decimal number including the century.

%Z     The time zone or name or abbreviation.

%%     A literal `%' character.