%a   # Sun          weekday abbrev
%A   # Sunday       weekday full
%w   # 0            weekday decimal (0=Sun, 6=Sat)
%d   # 08           day of month, zero-padded
%-d  # 8            day of month (platform specific)
%b   # Sep          month abbrev
%B   # September    month full
%m   # 09           month, zero-padded
%-m  # 9            month (platform specific)
%y   # 13           year w/o century, zero-padded
%Y   # 2013         year w/ century
%H   # 07           hour 24h, zero-padded
%-H  # 7            hour 24h (platform specific)
%I   # 07           hour 12h, zero-padded
%-I  # 7            hour 12h (platform specific)
%p   # AM           AM/PM
%M   # 06           minute, zero-padded
%-M  # 6            minute (platform specific)
%S   # 05           second, zero-padded
%-S  # 5            second (platform specific)
%f   # 000000       microsecond, 6-digit zero-padded
%z   # +0000        UTC offset ±HHMM[SS[.ffffff]] (empty if naive)
%Z   # UTC          tz name (empty if naive)
%j   # 251          day of year, zero-padded
%-j  # 251          day of year (platform specific)
%U   # 36           week# (Sun first), zero-padded; pre-first-Sun=week 0
%-U  # 36           week# (Sun first) (platform specific)
%W   # 35           week# (Mon first), zero-padded; pre-first-Mon=week 0
%-W  # 35           week# (Mon first) (platform specific)
%c   # Sun Sep 8 07:06:05 2013   locale date+time
%x   # 09/08/13     locale date
%X   # 07:06:05     locale time
%%   # %            literal %