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

NAME
       zdump - time zone dumper

SYNOPSIS
       zdump [ option ... ] [ 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 N seconds east of
              Greenwich.

       -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.

       -c [loyear,]hiyear
              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,]hitime
              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 exclusive and
              its upper bound is inclusive.

LIMITATIONS
       Time discontinuities are found by sampling the results returned by
       localtime 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
       newctime(3), tzfile(5), zic(8)

                                                                      ZDUMP(8)
