64 lines
1.5 KiB
Groff
64 lines
1.5 KiB
Groff
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.\"
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.\" @(#)zdump.8 8.2
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.\" This file is in the public domain, so clarified as of
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.\" 2009-05-17 by Arthur David Olson.
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.\" $FreeBSD$
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.\"
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.Dd June 20, 2004
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.Dt ZDUMP 8
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.Os
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.Sh NAME
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.Nm zdump
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.Nd timezone dumper
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.Sh SYNOPSIS
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.Nm
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.Op Fl -version
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.Op Fl v
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.Op Fl c Ar [loyear,]hiyear
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.Op Ar zonename ...
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.Sh DESCRIPTION
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The
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.Nm
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utility prints the current time in each
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.Ar zonename
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named on the command line.
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.Pp
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The following options are available:
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.Bl -tag -width indent
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.It Fl -version
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Output version information and exit.
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.It Fl v
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For each
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.Ar zonename
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on the command line,
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print the time at the lowest possible time value,
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the time one day after the lowest possible time value,
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the times both one second before and exactly at
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each detected time discontinuity,
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the time at one day less than the highest possible time value,
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and the time at the highest possible time value,
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Each line ends with
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.Em isdst=1
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if the given time is Daylight Saving Time or
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.Em isdst=0
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otherwise.
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.It Fl c Ar loyear,hiyear
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Cut off verbose output near the start of the given year(s).
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By default,
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the program cuts off verbose output near the starts of the years -500 and 2500.
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.El
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.Sh LIMITATIONS
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The
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.Fl v
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option may not be used on systems with floating-point time_t values
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that are neither float nor double.
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.Pp
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Time discontinuities are found by sampling the results returned by localtime
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at twelve-hour intervals.
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This works in all real-world cases;
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one can construct artificial time zones for which this fails.
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.Sh "SEE ALSO"
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.Xr ctime 3 ,
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.Xr tzfile 5 ,
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.Xr zic 8
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