DragonFly On-Line Manual Pages
ZDUMP(8) DragonFly System Manager's Manual ZDUMP(8)
zdump -- timezone dumper
zdump [-v] [-c [loyear,]hiyear] [zonename ...]
The zdump utility prints the current time in each zonename named on the
The following options are available:
-v For each zonename on the command line, print the time at the low-
est possible time value, the time one day after the lowest possi-
ble 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 pos-
sible time value, Each line ends with isdst=1 if the given time
is Daylight Saving Time or isdst=0 otherwise.
Cut off verbose output near the start of the given year(s). By
default, the program cuts off verbose output near the starts of
the years -500 and 2500.
The -v option may not be used on systems with floating-point time_t val-
ues that are neither float nor double.
Time discontinuities are found by sampling the results returned by
localtime(3) at twelve-hour intervals. This works in all real-world
cases; one can construct artificial time zones for which this fails.
ctime(3), tzfile(5), zic(8)
DragonFly 3.5 October 19, 2008 DragonFly 3.5