%W day of week Monday to Sunday
%a day of week abbreviated Mon to Sun
%e day of month 1 to 31
%d day of month two-digit 01 to 31
%D day of month with ending 1st, 2nd, 3rd, 4th, ...
%w day of week as number 0 (Sunday) to 6 (Saturday)
%j day in year, three-digit 001 to 366
%U week number, two-digit (Sunday) 00 to 52
%u week number, two-digit (Monday) 00 to 52
%M name of month January to December
%b name of month abbreviated Jan to Dec
%c month number 1 to i
%m month number, two-digit 01 to 12
%Y year, four-digit 2002, 2003, ...
%y year, two-digit 00, 01, ...
%% the symbol % %