full month name according to the current locale.
  %c
    The preferred date and time representation for the current
    locale (alt E)
  %C
    The century number (year/100) as a 2-digit integer. (alt E)
  %d
    The day of the month as a decimal number (range 01 to 31).
    (alt O)
  %D
    Equivalent to %m/%d/%y. (For Americans only. Americans should
    note that in other countries%d/%m/%y is rather common. This
    means that in international context this format is ambiguous and
    should not be used.
  %e
    Like %d, the day of the month as a decimal number, but a leading
    zero is replaced by a space. (alt O)
  %E
    Modifier: use alternative local-dependent representation if
    available.
  %F
    Equivalent to %Y-%m-%d (the ISO 8601 date format).
  %G
    The ISO 8601 week-based year with century as a decimal number.
    The 4-digit year corresponding to the ISO week number (see %V).
    This has the same format and value as %Y, except that if the
    ISO week number belongs to the previous or next year, that year
    is used instead.
  %g
    Like %G, but without century, that is, with a 2-digit year
    (00-99).
  %h
    Equivalent to %b.
  %H
    The hour as a decimal number using a 24-hour clock
    (range 00 to 23). (alt O)
  %I
    The hour as a decimal number using a 12-hour clock
    (range 01 to 12). (alt O)
  %j
    The day of the year as a decimal number (range 001 to 366).
  %k
    The hour (24-hour clock) as a decimal number (range 0 to 23);
    single digits are preceded by a blank. (See also %H.)
  %l
    The hour (12-hour clock) as a decimal number (range 1 to 12);
    single digits are preceded by a blank. (See also %I.)
  %m
    The month as a decimal number (range 01 to 12). (alt O)
  %M
    The minute as a decimal number (range 00 to 59). (alt O)
  %O
    Modifier: use alternative numeric symbols.
  %p
    Either "AM" or "PM" according to the given time value,
    or the corresponding strings for the current locale. Noon is
    treated as "PM" and midnight as "AM".
  %P
    Like %p but in lowercase: "am" or "pm" or a corresponding
    string for the current locale.
  %r
    The time in a.m. or p.m. notation. In the POSIX locale this is
    equivalent to %I:%M:%S %p.
  %R
    The time in 24-hour notation (%H:%M). For a version including
    the seconds, see %T below.
  %s
    The number of seconds since the Epoch,
    1970-01-01 00:00:00 +0000 (UTC)
  %S
    The second as a decimal number (range 00 to 60). (The range is
    up to 60 to allow for occasional leap seconds.) (alt O)
  %t
    A tab character.
  %T
    The time in 24-hour notation (%H:%M:%S).
  %u
    The day of the week as a decimal, range 1 to 7, Monday being 1.
    See also %w. (alt O)
  %U
    The week number of the current year as a decimal number,
    range 00 to 53, starting with the first Sunday as the first
    day of week 01. See also %V and %W. (alt O)
  %V
    The ISO 8601 week number of the current year as a decimal number,
    range 01 to 53, where week 1 is the first week that has at least
    4 days in the new year. See also %U and %W. (alt O)
  %w
    The day of the week as a decimal, range 0 to 6, Sunday being 0.
    See also %u. (alt O)
  %W
    The week number of the current year as a decimal number,
    range 00 to 53, starting with the first Monday as the first day
    of week 01. (alt O)
  %x
    The preferred date representation for the current locale without
    the time. (alt E)
  %X
    The preferred time representation for the current locale without
    the date. (alt E)
  %y
    The year as a decimal number without a century (range 00 to 99).
    (alt E, alt O)
  %Y
    The year as a decimal number including the century. (alt E)
  %z
    The +hhmm or -hhmm numeric timezone (that is, the hour and minute
    offset from UTC).
  %Z
    The timezone name or abbreviation.
  %%
    A literal '%' character.
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