zdump Command

Purpose

Displays the time zone information.

Syntax

zdump [--version] [--help] [-v] [-V] [-c [loyear,]hiyear] [-t [lotime,]hitime] zonename ...

Description

The zdump command prints the time zone information for each zone name that is specified in the command line.

Flags

Item Description
--version Displays the version information of the zdump command.
-v For each zone name that is specified in the command line, the zdump command prints the following items:
  • The lowest possible value of time.
  • The time at one day after the lowest possible value of time.
  • The times both one second before and exactly at each detected discontinuity of time.
  • The highest possible value of time.
  • The time at one day before the highest possible value of time.
Each line is followed by isdst=D, where D is a positive, zero, or negative value that depends on whether the specified time is Daylight Saving Time, standard time, or an unknown time type. Each line is also followed by gmtoff=N, where the specified local time is N seconds east of Greenwich.
-V Prints an output that is similar to the output of the -v flag except that this flag does not display the times that are relative to the extreme time values. This flag generates output that is easier to compare with different time representations.
-c [loyear,]hiyear Reports the verbose output for the specified years. Cutoff time is computed by using the proleptic Gregorian calendar with year 0 and Universal Time (UT) ignoring leap seconds. The lower year attribute (loyear) is exclusive and the upper year attribute (hiyear) is inclusive. For example, a loyear value of 1970 excludes a transition that occurs at 1970-01-01 00:00:00 Coordinated Universal Time, but a hiyear value of 1970 includes the transition. The default cutoff time is -500,2500.
-t [lotime,]hitime Reports verbose output for a particular time that is specified in the lotime and hitime attributes in the syntax of yyyy-mm-dd hh:mm:ss Coordinated Universal Time (UTC). For example, 1970-01-01 00:00:00. The cutoff time includes the leap seconds depending on the zonename parameter.

Similar to the -c flag, the lower time limit is exclusive and the upper time limit is inclusive.

Parameters

Item Description
zonename Represents the name of the zone of which the time zone information is displayed.

Exit Status

0
The command completed successfully.
>0
An error occurred.

Examples

  1. To report time zone information for Singapore, enter the following command: 
    zdump -v Singapore
  2. To display time zone information for Turkey stopping near the start of the year 2035, enter the following command:
    zdump -v -c 2035 Turkey
  3. To report the time zone information for New York during the years 2015 - 2017, enter the following command:
    zdump -v -c 2015,2017 America/New_York
    The output will be similar to the following sample:
    America/New_York  Fri Dec 13 20:45:52 1901 UT = Fri Dec 13 15:45:52 1901 EST isdst=0 gmtoff=-18000
America/New_York  Sat Dec 14 20:45:52 1901 UT = Sat Dec 14 15:45:52 1901 EST isdst=0 gmtoff=-18000
America/New_York  Sun Mar  8 06:59:59 2015 UT = Sun Mar  8 01:59:59 2015 EST isdst=0 gmtoff=-18000
America/New_York  Sun Mar  8 07:00:00 2015 UT = Sun Mar  8 03:00:00 2015 EDT isdst=1 gmtoff=-14400
America/New_York  Sun Nov  1 05:59:59 2015 UT = Sun Nov  1 01:59:59 2015 EDT isdst=1 gmtoff=-14400
America/New_York  Sun Nov  1 06:00:00 2015 UT = Sun Nov  1 01:00:00 2015 EST isdst=0 gmtoff=-18000
America/New_York  Sun Mar 13 06:59:59 2016 UT = Sun Mar 13 01:59:59 2016 EST isdst=0 gmtoff=-18000
America/New_York  Sun Mar 13 07:00:00 2016 UT = Sun Mar 13 03:00:00 2016 EDT isdst=1 gmtoff=-14400
America/New_York  Sun Nov  6 05:59:59 2016 UT = Sun Nov  6 01:59:59 2016 EDT isdst=1 gmtoff=-14400
America/New_York  Sun Nov  6 06:00:00 2016 UT = Sun Nov  6 01:00:00 2016 EST isdst=0 gmtoff=-18000
America/New_York  Mon Jan 18 03:14:07 2038 UT = Sun Jan 17 22:14:07 2038 EST isdst=0 gmtoff=-18000
America/New_York  Tue Jan 19 03:14:07 2038 UT = Mon Jan 18 22:14:07 2038 EST isdst=0 gmtoff=-18000
  4. To report the time zone information for New York during the years 2015 - 2017 without the lowest and highest time values, enter the following command:
    zdump -V -c 2015,2017 America/New_York
    The output will be similar to the following sample:
    America/New_York  Sun Mar  8 06:59:59 2015 UT = Sun Mar  8 01:59:59 2015 EST isdst=0 gmtoff=-18000
America/New_York  Sun Mar  8 07:00:00 2015 UT = Sun Mar  8 03:00:00 2015 EDT isdst=1 gmtoff=-14400
America/New_York  Sun Nov  1 05:59:59 2015 UT = Sun Nov  1 01:59:59 2015 EDT isdst=1 gmtoff=-14400
America/New_York  Sun Nov  1 06:00:00 2015 UT = Sun Nov  1 01:00:00 2015 EST isdst=0 gmtoff=-18000
America/New_York  Sun Mar 13 06:59:59 2016 UT = Sun Mar 13 01:59:59 2016 EST isdst=0 gmtoff=-18000
America/New_York  Sun Mar 13 07:00:00 2016 UT = Sun Mar 13 03:00:00 2016 EDT isdst=1 gmtoff=-14400
America/New_York  Sun Nov  6 05:59:59 2016 UT = Sun Nov  6 01:59:59 2016 EDT isdst=1 gmtoff=-14400
America/New_York  Sun Nov  6 06:00:00 2016 UT = Sun Nov  6 01:00:00 2016 EST isdst=0 gmtoff=-18000

Files

Item Description
/usr/sbin/zdump Contains the SystemV zdump command.
/usr/share/lib/zoneinfo Contains the standard time zone directory.