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

NAME

       zic - time zone compiler

SYNOPSIS

       zic [ -v ] [ -d directory ] [ -l localtime ] [ filename ... ]

DESCRIPTION

       Zic  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.

       These options are available:

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

       -l timezone
	      Use the given time zone as local time.  Zic will act as if the file contained a link line of the form

		   Link timezone       localtime

       -v     Complain if a year that appears in a data file is outside the range of years representable by time(2) values.

	      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're	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.

       A rule line has the form

	    Rule  NAME	FROM  TO    TYPE  IN   ON	AT    SAVE  LETTER/S

       For example:

	    Rule  USA	1969  1973  -	  Apr  lastSun	2:00  1:00  D

       The fields that make up a rule line are:

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

       FROM    Gives the first year in which the rule applies.	The word minimum (or an abbreviation) means the minimum year with a  representable
	       time value.  The word maximum (or an abbreviation) means the maximum year with a representable time value.

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

       TYPE    Gives the type of year in which the year applies.  If TYPE is - then the rule applies in all years between FROM and  TO	inclusive;
	       if  TYPE  is uspres, the rule applies in U.S. Presidential election years; if TYPE is nonpres, the rule applies in years other than
	       U.S. Presidential election years.  If TYPE is something else, then zic executes 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      Names the month in which the rule takes effect.	Month names may be abbreviated.

       ON      Gives 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      Gives the time of day at which the rule takes affect.  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

	       Any  of	these forms may be followed by the letter w if the given time is local ``wall clock'' time or s if the given time is local
	       ``standard'' time; in the absence of w or s, wall clock time is assumed.

       SAVE    Gives 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
	       Gives 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  [UNTIL]

       For example:

	    Zone  Australia/South-west	9:30	Aus	    CST     1987 Mar 15 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 GMT 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 GMT.

       RULES/SAVE
	     The  name of the rule(s) that apply in the time zone or, alternately, 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.	UNTIL The time at which the GMT 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 generated from the given GMT offset  and
	     rule change until the time specified.

	     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 field in the	previous  line	in
	     the  file	used by the previous line.  Continuation lines may contain an UNTIL field, 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  US/Eastern  EST5EDT

       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.

NOTE

       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.

FILES

       /usr/share/zoneinfostandard directory used for created files

SEE ALSO

       newctime(3), tzfile(5), zdump(8)

																	    ZIC(8)