tar: Time of day items

1 
1 7.3 Time of day items
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1 
1 A "time of day item" in date strings specifies the time on a given day.
1 Here are some examples, all of which represent the same time:
1 
1      20:02:00.000000
1      20:02
1      8:02pm
1      20:02-0500      # In EST (U.S. Eastern Standard Time).
1 
1    More generally, the time of day may be given as 'HOUR:MINUTE:SECOND',
1 where HOUR is a number between 0 and 23, MINUTE is a number between 0
1 and 59, and SECOND is a number between 0 and 59 possibly followed by '.'
1 or ',' and a fraction containing one or more digits.  Alternatively,
1 ':SECOND' can be omitted, in which case it is taken to be zero.  On the
1 rare hosts that support leap seconds, SECOND may be 60.
1 
1    If the time is followed by 'am' or 'pm' (or 'a.m.' or 'p.m.'), HOUR
1 is restricted to run from 1 to 12, and ':MINUTE' may be omitted (taken
1 to be zero).  'am' indicates the first half of the day, 'pm' indicates
1 the second half of the day.  In this notation, 12 is the predecessor of
1 1: midnight is '12am' while noon is '12pm'.  (This is the zero-oriented
1 interpretation of '12am' and '12pm', as opposed to the old tradition
1 derived from Latin which uses '12m' for noon and '12pm' for midnight.)
1 
1    The time may alternatively be followed by a time zone correction,
1 expressed as 'SHHMM', where S is '+' or '-', HH is a number of zone
1 hours and MM is a number of zone minutes.  The zone minutes term, MM,
1 may be omitted, in which case the one- or two-digit correction is
1 interpreted as a number of hours.  You can also separate HH from MM with
1 a colon.  When a time zone correction is given this way, it forces
1 interpretation of the time relative to Coordinated Universal Time (UTC),
1 overriding any previous specification for the time zone or the local
1 time zone.  For example, '+0530' and '+05:30' both stand for the time
1 zone 5.5 hours ahead of UTC (e.g., India).  This is the best way to
1 specify a time zone correction by fractional parts of an hour.  The
1 maximum zone correction is 24 hours.
1 
1    Either 'am'/'pm' or a time zone correction may be specified, but not
1 both.
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