xref: /openbsd-src/usr.sbin/zdump/zdump.8 (revision d32639f6ddc06f615d8e07a47d97091b3531a48f)
1*d32639f6Sjmc.\"	$OpenBSD: zdump.8,v 1.3 2022/09/11 06:38:12 jmc Exp $
2*d32639f6Sjmc.Dd $Mdocdate: September 11 2022 $
32059035fStedu.Dt ZDUMP 8
42059035fStedu.Os
52059035fStedu.Sh NAME
62059035fStedu.Nm zdump
72059035fStedu.Nd time zone dumper
82059035fStedu.Sh SYNOPSIS
92059035fStedu.Nm zdump
102059035fStedu.Op Fl v
112059035fStedu.Oo
122059035fStedu.Fl c
132059035fStedu.Oo Ar loyear , Oc Ar hiyear
142059035fStedu.Oc
152059035fStedu.Ar zonename ...
162059035fStedu.Sh DESCRIPTION
172059035fStedu.Nm
182059035fSteduprints the current time in each
192059035fStedu.Ar zonename
202059035fStedunamed on the command line.
212059035fStedu.Pp
222059035fSteduThese options are available:
232a110ee1Sschwarze.Bl -tag -width Ds
242059035fStedu.It Xo
252059035fStedu.Fl c
262059035fStedu.Oo Ar loyear , Oc Ar hiyear
272059035fStedu.Xc
282059035fSteduCut off verbose output near the start of the given year(s).
292059035fSteduBy default,
302059035fSteduthe program cuts off verbose output near the start of the years -500 and 2500.
312059035fStedu.It Fl v
322059035fSteduFor each
332059035fStedu.Ar zonename
342059035fSteduon the command line,
352059035fSteduprint the time at the lowest possible time value,
362059035fSteduthe time one day after the lowest possible time value,
372059035fSteduthe times both one second before and exactly at
382059035fStedueach detected time discontinuity,
392059035fSteduthe time at one day less than the highest possible time value,
402059035fSteduand the time at the highest possible time value.
412059035fSteduEach line ends with
422059035fStedu.Dq isdst=1
432059035fSteduif the given time is Daylight Saving Time or
442059035fStedu.Dq isdst=0
452059035fSteduotherwise.
462059035fStedu.El
472059035fStedu.Sh LIMITATIONS
482059035fSteduThe
492059035fStedu.Fl v
502059035fSteduoption may not be used on systems with floating-point
51*d32639f6Sjmc.Vt time_t
522059035fSteduvalues that are neither float nor double.
532059035fStedu.Pp
542059035fSteduTime discontinuities are found by sampling the results returned by localtime
552059035fSteduat twelve-hour intervals.
562059035fSteduThis works in all real-world cases;
572059035fStedu.\" @(#)zdump.8	8.1
582059035fStedu.Sh SEE ALSO
592059035fStedu.Xr ctime 3 ,
602059035fStedu.Xr tzfile 5 ,
612059035fStedu.Xr zic 8
622059035fStedu.\" This file is in the public domain, so clarified as of
632059035fStedu.\" 2009-05-17 by Arthur David Olson.
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