1.\" $NetBSD: zdump.8,v 1.11 2013/09/20 19:06:54 christos Exp $ 2.Dd September 20, 2013 3.Dt ZDUMP 8 4.Os 5.Sh NAME 6.Nm zdump 7.Nd time zone dumper 8.Sh SYNOPSIS 9.Nm zdump 10.Op Fl \-version 11.Op Fl v 12.Op Fl V 13.Op Fl c Ar [loyear,]highyear 14.Op Ar zonename ... 15.Nm zdump 16.Fl t 17.Ar [loyear,]highyear 18.Op Ar zonename ... 19.Sh DESCRIPTION 20.Nm 21prints the current time in each 22.Ar zonename 23named on the command line. 24.Pp 25These options are available: 26.Bl -tag -width XXXXXXXXX -compact 27.It Fl \-version 28Output version information and exit. 29.It Fl v 30For each 31.Ar zonename 32on the command line, 33print the time at the lowest possible time value, 34the time one day after the lowest possible time value, 35the times both one second before and exactly at 36each detected time discontinuity, 37the time at one day less than the highest possible time value, 38and the time at the highest possible time value, 39Each line ends with 40.Dl isdst=1 41if the given time is Daylight Saving Time or 42.Dl isdst=0 43otherwise. 44.It Fl c Ar [loyear,]highyear 45Cut off the verbose output near the start of the given year(s). 46By default, 47the program cuts off verbose output near the starts of the years \-500 and 2500. 48.It Fl t Ar [loyear,]highyear 49Cut off verbose output at the start of the given time(s), 50given in decimal seconds since 1970-01-01 00:00:00 UTC. 51.It Fl V 52Like 53.Fl v , 54except omit the times relative to the extreme time values. 55This generates output that is easier to compare to that of 56implementations with different time representations. 57.El 58.Sh LIMITATIONS 59Time discontinuities are found by sampling the results returned by localtime 60at twelve-hour intervals. 61This works in all real-world cases; 62one can construct artificial time zones for which this fails. 63.Pp 64In the output, 65.Dq UT 66denotes the value returned by 67.Xr gmtime 3 , 68which uses UTC for modern time stamps and some other UT flavor for 69time stamps that predate the introduction of UTC. 70No attempt is currently made to have the output use 71.Dq UTC 72for newer and 73.Dq UT 74for older time stamps, 75partly because the exact date of the introduction of UTC is problematic. 76.Sh SEE ALSO 77.Xr ctime 3 , 78.Xr tzfile 5 , 79.Xr zic 8 80.\" @(#)zdump.8 8.2 81.\" This file is in the public domain, so clarified as of 82.\" 2009-05-17 by Arthur David Olson. 83