%%     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., 21)

   %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 ( 0..23)

   %l     hour ( 1..12)

   %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 timezone (e.g., -0400)

   %:z    +hh:mm numeric timezone (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)