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       zdump - timezone dumper


       zdump [ option ... ] [ timezone ... ]


       The zdump program prints the current time in each timezone named on the command line.


              Output version information and exit.

       --help Output short usage message and exit.

       -i     Output  a  description  of  time intervals.  For each timezone on the command line,
              output an interval-format description  of  the  timezone.   See  “INTERVAL  FORMAT”

       -v     Output  a  verbose description of time intervals.  For each timezone 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

       -c [loyear,]hiyear
              Cut  off interval 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.  Cutoffs are at the start of each year, where the lower-bound timestamp is
              exclusive and the upper is inclusive; for example, -c 1970,2070 selects transitions
              after  1970-01-01  00:00:00  UTC  and  on  or  before 2070-01-01 00:00:00 UTC.  The
              default cutoff is -500,2500.

       -t [lotime,]hitime
              Cut off interval output at the  given  time(s),  given  in  decimal  seconds  since
              1970-01-01  00:00:00  Coordinated  Universal  Time  (UTC).  The timezone determines
              whether the count includes leap seconds.  As with -c, the cutoff's lower  bound  is
              exclusive and its upper bound is inclusive.


       The  interval  format  is a compact text representation that is intended to be both human-
       and machine-readable.  It consists of an empty line, then a line “TZ=string” where  string
       is a double-quoted string giving the timezone, a second line “- - interval” describing the
       time interval before the first transition if any, and zero or more following  lines  “date
       time  interval”,  one  line  for  each transition time and following interval.  Fields are
       separated by single tabs.

       Dates are in yyyy-mm-dd format and times are  in  24-hour  hh:mm:ss  format  where  hh<24.
       Times  are  in  local  time immediately after the transition.  A time interval description
       consists of a UT offset in signed ±hhmmss format, a time zone abbreviation, and  an  isdst
       flag.   An  abbreviation  that  equals  the  UT offset is omitted; other abbreviations are
       double-quoted strings unless they consist of one or more alphabetic characters.  An  isdst
       flag is omitted for standard time, and otherwise is a decimal integer that is unsigned and
       positive (typically 1) for daylight saving time and negative for unknown.

       In times and in UT offsets with absolute value  less  than  100  hours,  the  seconds  are
       omitted  if  they  are  zero,  and  the  minutes  are  also omitted if they are also zero.
       Positive UT offsets are east of Greenwich.  The UT offset -00 denotes a UT placeholder  in
       areas  where  the  actual  offset  is  unspecified; by convention, this occurs when the UT
       offset is zero and the time zone abbreviation begins with “-” or is “zzz”.

       In double-quoted strings, escape  sequences  represent  unusual  characters.   The  escape
       sequences are \s for space, and \", \\, \f, \n, \r, \t, and \v with their usual meaning in
       the C programming language.  E.g., the double-quoted string “"CET\s\"\\"”  represents  the
       character sequence “CET "\”.

       Here  is  an example of the output, with the leading empty line omitted.  (This example is
       shown with tab stops set far enough apart so that the tabbed columns line up.)

         -           -         -103126  LMT
         1896-01-13  12:01:26  -1030    HST
         1933-04-30  03        -0930    HDT  1
         1933-05-21  11        -1030    HST
         1942-02-09  03        -0930    HWT  1
         1945-08-14  13:30     -0930    HPT  1
         1945-09-30  01        -1030    HST
         1947-06-08  02:30     -10      HST

       Here, local time begins 10 hours, 31 minutes and 26 seconds west of UT, and is a  standard
       time  abbreviated LMT.  Immediately after the first transition, the date is 1896-01-13 and
       the time is 12:01:26, and the following time interval is 10.5 hours west of UT, a standard
       time abbreviated HST.  Immediately after the second transition, the date is 1933-04-30 and
       the time is 03:00:00 and the  following  time  interval  is  9.5  hours  west  of  UT,  is
       abbreviated  HDT,  and is daylight saving time.  Immediately after the last transition the
       date is 1947-06-08 and the time is 02:30:00, and the following time interval is  10  hours
       west of UT, a standard time abbreviated HST.

       Here are excerpts from another example:

         -           -         +031212  LMT
         1924-04-30  23:47:48  +03
         1930-06-21  01        +04
         1981-04-01  01        +05           1
         1981-09-30  23        +04
         2014-10-26  01        +03
         2016-03-27  03        +04

       This time zone is east of UT, so its UT offsets are positive.  Also, many of its time zone
       abbreviations are omitted since they duplicate the text of the UT offset.


       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 -v and -V output, “UT” denotes the value returned by gmtime(3), which uses UTC  for
       modern timestamps and some other UT flavor for timestamps that predate the introduction of
       UTC.  No attempt is currently made to have the output use “UTC” for  newer  and  “UT”  for
       older timestamps, partly because the exact date of the introduction of UTC is problematic.


       tzfile(5), zic(8)


       This  page  is  part of release 5.10 of the Linux man-pages project.  A description of the
       project, information about reporting bugs, and the latest version of  this  page,  can  be
       found at

                                            2020-04-27                                   ZDUMP(8)