minix/lib/libc/time/zdump.8
Ben Gras 2fe8fb192f Full switch to clang/ELF. Drop ack. Simplify.
There is important information about booting non-ack images in
docs/UPDATING. ack/aout-format images can't be built any more, and
booting clang/ELF-format ones is a little different. Updating to the
new boot monitor is recommended.

Changes in this commit:

	. drop boot monitor -> allowing dropping ack support
	. facility to copy ELF boot files to /boot so that old boot monitor
	  can still boot fairly easily, see UPDATING
	. no more ack-format libraries -> single-case libraries
	. some cleanup of OBJECT_FMT, COMPILER_TYPE, etc cases
	. drop several ack toolchain commands, but not all support
	  commands (e.g. aal is gone but acksize is not yet).
	. a few libc files moved to netbsd libc dir
	. new /bin/date as minix date used code in libc/
	. test compile fix
	. harmonize includes
	. /usr/lib is no longer special: without ack, /usr/lib plays no
	  kind of special bootstrapping role any more and bootstrapping
	  is done exclusively through packages, so releases depend even
	  less on the state of the machine making them now.
	. rename nbsd_lib* to lib*
	. reduce mtree
2012-02-14 14:52:02 +01:00

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.\" $NetBSD: zdump.8,v 1.8 2010/01/08 23:14:13 joerg Exp $
.\" @(#)zdump.8 7.4
.Dd October 29, 2003
.Dt ZDUMP 8
.Os
.Sh NAME
.Nm zdump
.Nd time zone dumper
.Sh SYNOPSIS
.Nm zdump
.Op Fl \-version
.Op Fl v
.Op Fl c Ar [loyear,]highyear
.Op Ar zonename ...
.Sh DESCRIPTION
.Nm
prints the current time in each
.Ar zonename
named on the command line.
.Pp
These options are available:
.Bl -tag -width XXXXXXXXX -compact
.It Fl \-version
Output version information and exit.
.It Fl v
For each
.Ar zonename
on the command line,
print the time at the lowest possible time value,
the time one day after the lowest possible 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 possible time value,
Each line ends with
.Dl isdst=1
if the given time is Daylight Saving Time or
.Dl isdst=0
otherwise.
.It Fl c Ar [loyear,]highyear
Cut off the 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.
.El
.Sh LIMITATIONS
The
.Fl v
option may not be used on systems with floating-point time_t values
that are neither float nor double.
.Pp
Time discontinuities are found by sampling the results returned by localtime
at twelve-hour intervals.
This works in all real-world cases;
one can construct artificial time zones for which this fails.
.Sh SEE ALSO
.Xr ctime 3 ,
.Xr tzfile 5 ,
.Xr zic 8
.\" @(#)zdump.8 8.2
.\" This file is in the public domain, so clarified as of
.\" 2009-05-17 by Arthur David Olson.