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ZIC(8)			FreeBSD	System Manager's Manual			ZIC(8)

NAME
     zic -- timezone compiler

SYNOPSIS
     zic [--version] [-Dsv] [-d	directory] [-g group] [-L leapsecondfilename]
	 [-l localtime]	[-m mode] [-p posixrules] [-u user] [-y	command]
	 [filename ...]

DESCRIPTION
     The zic utility reads text	from the file(s) named on the command line and
     creates the time conversion information files specified in	this input.
     If	a filename is -, the standard input is read.

     The following options are available:

     --version
	     Output version information	and exit.

     -D	     Do	not automatically create directories.  If the input file(s)
	     specify an	output file in a directory which does not already
	     exist, the	default	behavior is to attempt to create the direc-
	     tory.  If -D is specified,	zic will instead error out immedi-
	     ately.

     -d	directory
	     Create time conversion information	files in the named directory
	     rather than in the	standard directory named below.

     -g	group
	     After creating each output	file, change its group ownership to
	     the specified group (which	can be either a	name or	a numeric
	     group ID).

     -L	leapsecondfilename
	     Read leap second information from the file	with the given name.
	     If	this option is not used, no leap second	information appears in
	     output files.

     -l	timezone
	     Use the given time	zone as	local time.  The zic utility will act
	     as	if the input contained a link line of the form

		   Link	timezone       localtime

	     (Note that	this action has	no effect on FreeBSD, since the	local
	     time zone is specified in /etc/localtime and not
	     /usr/share/zoneinfo/localtime.)

     -m	mode
	     After creating each output	file, change its access	mode to	mode.
	     Both numeric and alphabetic modes are accepted (see chmod(1)).

     -p	timezone
	     Use the given time	zone's rules when handling POSIX-format	time
	     zone environment variables.  The zic utility will act as if the
	     input contained a link line of the	form

		   Link	timezone       posixrules

     -u	user
	     After creating each output	file, change its owner to user (which
	     can be either a name or a numeric user ID).

     -v	     Complain if a year	that appears in	a data file is outside the
	     range of years representable by time(3) values.

     -s	     Limit time	values stored in output	files to values	that are the
	     same whether they are taken to be signed or unsigned.  You	can
	     use this option to	generate SVVS-compatible files.

     -y	command
	     Use the given command rather than yearistype when checking	year
	     types (see	below).

     Input lines are made up of	fields.	 Fields	are separated from one another
     by	any number of white space characters.  Leading and trailing white
     space on input lines is ignored.  An unquoted sharp character (#) in the
     input introduces a	comment	which extends to the end of the	line the sharp
     character appears on.  White space	characters and sharp characters	may be
     enclosed in double	quotes (") if they are to be used as part of a field.
     Any line that is blank (after comment stripping) is ignored.  Non-blank
     lines are expected	to be of one of	three types: rule lines, zone lines,
     and link lines.

     Names (such as month names) must be in English and	are case insensitive.
     Abbreviations, if used, must be unambiguous in context.

     A rule line has the form:
	   Rule	NAME FROM TO   TYPE IN	 ON	   AT	SAVE LETTER/S
     For example:
	   Rule	US   1967 1973 -    Apr	 lastSun   2:00	1:00 D

     The fields	that make up a rule line are:

	   NAME	     Give the (arbitrary) name of the set of rules this	rule
		     is	part of.

	   FROM	     Give the first year in which the rule applies.  Any inte-
		     ger year can be supplied; the Gregorian calendar is
		     assumed.  The word	minimum	(or an abbreviation) means the
		     minimum year representable	as an integer.	The word
		     maximum (or an abbreviation) means	the maximum year rep-
		     resentable	as an integer.	Rules can describe times that
		     are not representable as time values, with	the unrepre-
		     sentable times ignored; this allows rules to be portable
		     among hosts with differing	time value types.

	   TO	     Give the final year in which the rule applies.  In	addi-
		     tion to minimum and maximum (as above), the word only (or
		     an	abbreviation) may be used to repeat the	value of the
		     FROM field.

	   TYPE	     Give the type of year in which the	rule applies.  If TYPE
		     is	- then the rule	applies	in all years between FROM and
		     TO	inclusive.  If TYPE is something else, then zic	exe-
		     cutes the command yearistype year type to check the type
		     of	a year:	an exit	status of zero is taken	to mean	that
		     the year is of the	given type; an exit status of one is
		     taken to mean that	the year is not	of the given type.

	   IN	     Name the month in which the rule takes effect.  Month
		     names may be abbreviated.

	   ON	     Give the day on which the rule takes effect.  Recognized
		     forms include:

			   5	    the	fifth of the month
			   lastSun  the	last Sunday in the month
			   lastMon  the	last Monday in the month
			   Sun>=8   first Sunday on or after the eighth
			   Sun<=25  last Sunday	on or before the 25th

		     Names of days of the week may be abbreviated or spelled
		     out in full.  Note	that there must	be no spaces within
		     the ON field.

	   AT	     Give the time of day at which the rule takes effect.
		     Recognized	forms include:

			   2	    time in hours
			   2:00	    time in hours and minutes
			   15:00    24-hour format time	(for times after noon)
			   1:28:14  time in hours, minutes, and	seconds

		     where hour	0 is midnight at the start of the day, and
		     hour 24 is	midnight at the	end of the day.	 Any of	these
		     forms may be followed by the letter `w' if	the given time
		     is	local ``wall clock'' time, `s' if the given time is
		     local ``standard''	time, or `u' (or `g' or	`z') if	the
		     given time	is universal time; in the absence of an	indi-
		     cator, wall clock time is assumed.

	   SAVE	     Give the amount of	time to	be added to local standard
		     time when the rule	is in effect.  This field has the same
		     format as the AT field (although, of course, the `w' and
		     `s' suffixes are not used).

	   LETTER/S  Give the ``variable part''	(for example, the ``S''	or
		     ``D'' in ``EST'' or ``EDT'') of time zone abbreviations
		     to	be used	when this rule is in effect.  If this field is
		     -,	the variable part is null.

     A zone line has the form:
	   Zone	NAME GMTOFF    RULES/SAVE     FORMAT	[UNTILYEAR [MONTH [DAY
	   [TIME]]]]
     For example:
	   Zone	Australia/Adelaide  9:30 Aus  CST  1971	Oct 31 2:00
     The fields	that make up a zone line are:

     NAME    The name of the time zone.	 This is the name used in creating the
	     time conversion information file for the zone.

     GMTOFF  The amount	of time	to add to UTC to get standard time in this
	     zone.  This field has the same format as the AT and SAVE fields
	     of	rule lines; begin the field with a minus sign if time must be
	     subtracted	from UTC.

     RULES/SAVE
	     The name of the rule(s) that apply	in the time zone or, alter-
	     nately, an	amount of time to add to local standard	time.  If this
	     field is -	then standard time always applies in the time zone.

     FORMAT  The format	for time zone abbreviations in this time zone.	The
	     pair of characters	%s is used to show where the ``variable	part''
	     of	the time zone abbreviation goes.  Alternately, a slash (/)
	     separates standard	and daylight abbreviations.

     UNTILYEAR [MONTH [DAY [TIME]]]
	     The time at which the UTC offset or the rule(s) change for	a
	     location.	It is specified	as a year, a month, a day, and a time
	     of	day.  If this is specified, the	time zone information is gen-
	     erated from the given UTC offset and rule change until the	time
	     specified.	 The month, day, and time of day have the same format
	     as	the IN,	ON, and	AT fields of a rule; trailing fields can be
	     omitted, and default to the earliest possible value for the miss-
	     ing fields.

	     The next line must	be a ``continuation'' line; this has the same
	     form as a zone line except	that the string	``Zone'' and the name
	     are omitted, as the continuation line will	place information
	     starting at the time specified as the until information in	the
	     previous line in the file used by the previous line.  Continua-
	     tion lines	may contain until information, just as zone lines do,
	     indicating	that the next line is a	further	continuation.

     A link line has the form
	   Link	LINK-FROM LINK-TO
     For example:
	   Link	Europe/Istanbul	    Asia/Istanbul
     The LINK-FROM field should	appear as the NAME field in some zone line;
     the LINK-TO field is used as an alternate name for	that zone.

     Except for	continuation lines, lines may appear in	any order in the
     input.

     Lines in the file that describes leap seconds have	the following form:
	   Leap	YEAR MONTH     DAY  HH:MM:SS  CORR R/S
     For example:
	   Leap	1974 Dec  31   23:59:60	 +    S
     The YEAR, MONTH, DAY, and HH:MM:SS	fields tell when the leap second hap-
     pened.  The CORR field should be ``+'' if a second	was added or ``-'' if
     a second was skipped.  The	R/S field should be (an	abbreviation of)
     ``Stationary'' if the leap	second time given by the other fields should
     be	interpreted as UTC or (an abbreviation of) ``Rolling'' if the leap
     second time given by the other fields should be interpreted as local wall
     clock time.

EXTENDED EXAMPLE
     Here is an	extended example of zic	input, intended	to illustrate many of
     its features.

       # Rule  NAME  FROM  TO	 TYPE  IN   ON	     AT	   SAVE	 LETTER/S
       Rule    Swiss 1940  only	 -     Nov  2	     0:00  1:00	 S
       Rule    Swiss 1940  only	 -     Dec  31	     0:00  0	 -
       Rule    Swiss 1941  1942	 -     May  Sun>=1   2:00  1:00	 S
       Rule    Swiss 1941  1942	 -     Oct  Sun>=1   0:00  0
       Rule    EU    1977  1980	 -     Apr  Sun>=1   1:00u 1:00	 S
       Rule    EU    1977  only	 -     Sep  lastSun  1:00u 0	 -
       Rule    EU    1978  only	 -     Oct   1	     1:00u 0	 -
       Rule    EU    1979  1995	 -     Sep  lastSun  1:00u 0	 -
       Rule    EU    1981  max	 -     Mar  lastSun  1:00u 1:00	 S
       Rule    EU    1996  max	 -     Oct  lastSun  1:00u 0	 -

       # Zone  NAME	      GMTOFF   RULES	   FORMAT  UNTIL
       Zone    Europe/Zurich  0:34:08  -	   LMT	   1848	Sep 12
			      0:29:44  -	   BMT	   1894	Jun
			      1:00     Swiss	   CE%sT   1981
			      1:00     EU	   CE%sT

       Link    Europe/Zurich  Switzerland

     In	this example, the zone is named	Europe/Zurich but it has an alias as
     Switzerland.  Zurich was 34 minutes and 8 seconds west of GMT until
     1848-09-12	at 00:00, when the offset changed to 29	minutes	and 44 sec-
     onds.  After 1894-06-01 at	00:00 Swiss daylight saving rules (defined
     with lines	beginning with "Rule Swiss") apply, and	the GMT	offset became
     one hour.	From 1981 to the present, EU daylight saving rules have
     applied, and the UTC offset has remained at one hour.

     In	1940, daylight saving time applied from	November 2 at 00:00 to Decem-
     ber 31 at 00:00.  In 1941 and 1942, daylight saving time applied from the
     first Sunday in May at 02:00 to the first Sunday in October at 00:00.
     The pre-1981 EU daylight-saving rules have	no effect here,	but are
     included for completeness.	 Since 1981, daylight saving has begun on the
     last Sunday in March at 01:00 UTC.	 Until 1995 it ended the last Sunday
     in	September at 01:00 UTC,	but this changed to the	last Sunday in October
     starting in 1996.

     For purposes of display, "LMT" and	"BMT" were initially used, respec-
     tively.  Since Swiss rules	and later EU rules were	applied, the display
     name for the timezone has been CET	for standard time and CEST for day-
     light saving time.

NOTES
     For areas with more than two types	of local time, you may need to use
     local standard time in the	AT field of the	earliest transition time's
     rule to ensure that the earliest transition time recorded in the compiled
     file is correct.

     If, for a particular zone,	a clock	advance	caused by the start of day-
     light saving coincides with and is	equal to a clock retreat caused	by a
     change in UTC offset, zic produces	a single transition to daylight	saving
     at	the new	UTC offset (without any	change in wall clock time).  To	get
     separate transitions use multiple zone continuation lines specifying
     transition	instants using universal time.

FILES
     /usr/share/zoneinfo  standard directory used for created files

SEE ALSO
     ctime(3), tzfile(5), zdump(8)

FreeBSD	10.1			 June 20, 2004			  FreeBSD 10.1

NAME | SYNOPSIS | DESCRIPTION | EXTENDED EXAMPLE | NOTES | FILES | SEE ALSO

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