zdump(8) - NetBSD Manual Pages

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ZDUMP(8)                NetBSD System Manager's Manual                ZDUMP(8)


NAME

     zdump -- time zone dumper


SYNOPSIS

     zdump [--version] [-v] [-V] [-c [loyear,]highyear] [zonename ...]
     zdump -t [lotime,]hightime [zonename ...]


DESCRIPTION

     zdump prints the current time in each zonename named on the command line.

     These options are available:
     --version  Output version information and exit.
     -v         For each zonename on the command line, print the time at the
                lowest possible time value, the time one day after the lowest
                possible time value, the times both one second before and
                exactly at each detected time discontinuity, the time at one
                day less than the highest possible time value, and the time at
                the highest possible time value.  Each line is followed by
                      isdst= D
                where
                      D
                is positive, zero, or negative depending on whether the given
                time is daylight saving time, standard time, or an unknown
                time type, respectively.  Each line is also followed by
                      gmtoff= N
                if the given local time is known to be seconds east of Green-
                wich.
     -c [loyear,]highyear
                Cut off verbose output at the given year(s).  Cutoff times are
                computed using the proleptic Gregorian calendar with year 0
                and with Universal Time (UT) ignoring leap seconds.  The lower
                bound is exclusive and the upper is inclusive; for example, a
                      loyear
                of 1970 excludes a transition occurring at 1970-01-01 00:00:00
                UTC but a
                      hiyear
                of 1970 includes the transition.  The default cutoff is
                      500,2500.
     -t [lotime,]hightime
                Cut off verbose output at the given time(s), given in decimal
                seconds since 1970-01-01 00:00:00 Coordinated Universal Time
                (UTC).  The zonename determines whether the count includes
                leap seconds.  As with -c, the cutoff's lower bound is exclu-
                sive and its upper bound is inclusive.
     -V         Like -v, except omit the times relative to the extreme time
                values.  This generates output that is easier to compare to
                that of implementations with different time representations.


LIMITATIONS

     Time discontinuities are found by sampling the results returned by local-
     time at twelve-hour intervals.  This works in all real-world cases; one
     can construct artificial time zones for which this fails.

     In the output, ``UT'' denotes the value returned by gmtime(3), which uses
     UTC for modern time stamps and some other UT flavor for time stamps that
     predate the introduction of UTC.  No attempt is currently made to have
     the output use ``UTC'' for newer and ``UT'' for older time stamps, partly
     because the exact date of the introduction of UTC is problematic.


SEE ALSO

     ctime(3), tzfile(5), zic(8)

NetBSD 7.0                     October 23, 2014                     NetBSD 7.0