UNIX Timestamp Formats

This format is used all over the place: many programming language datestamps, bash, MySQL, most UNIX prompts…
This data is from the man page from strftime, distilled down to basics. This is intended as a cheat-sheet, not an extremely-accurate dissertation. Ergo:
Some entries (marked with an asterisk) have extremely specific and perhaps unconventional ways of being counted; there are several ways to determine the week of the month, for example. I don’t bother trying to explain them here, because I don’t care. If you do, check out the strftime man page.
Some examples are locale-specific. The examples are from a US English locale.

Format	Name	Example(s)
%A	Full weekday name	Monday
%a	Abbreviated weekday name	Mon.
%B	Full month name	January
%b	Abbreviated month name	Jan.
%C	First two digits of year	20 (for 2009)
%c	Time and date	Fri May 29 18:42:15 2009
%D	Short for %m/%d/%y	05/29/09
%d	Day of the month (leading zero if applicable)	09 or 27
%e	Day of the month (no leading zero)	9 or 27
%F	Short for %Y-%m-%d	2009-05-29
%G	Full year* containing “the greater part of the week”	2009
%g	Last two digits of %g	09
%H	Hour, 24-hour format, leading zero if applicable	17 or 09
%h	Same as %b: abbrev. month name	Oct.
%I	Hour, 12-hour format	11 or 07
%j	Day of the year	365
%k	Hour, 24-hour format, without leading zero	17 or 9
%l	Hour, 12-hour format, without leading zero	11 or 7
%M	Minute, with leading zero if applicable	57 or 05
%m	Month, with leading zero if applicable	08
%n	Line break / newline (for formatting)
%p	AM or PM	AM
%R	Same as %H:%M	18:53
%r	Same as %I:%M:%S %p	06:53:43 PM
%S	Second, with leading zero	07 or 59
%s	Number of seconds since epoch	1243637689
%T	Same as %H:%M:%S	18:55:09
%t	Tab (for formatting)
%U	Week (number) of the year*	51
%v	Same as %e-%b-%Y	29-May-2009
%W	Week (number) of the year*	21
%w	Day of the week. Caveat: 0-6 (Sun-Sat)	6
%X	Time in local format	19:00:08
%x	Date in local format	05/29/2009
%Y	Full year	2009
%y	Short year (last two digits)	99
%Z	Time zone name	EDT
%z	Time zone difference from UTC (-0400: behind 4 hours, 00 minutes)	-0400
%+	Local date and time format	Fri May 29 19:06:31 EDT 2009
%%	A literal percent sign	%

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