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

Name
       zic - time zone compiler

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

Description
       The  compiler  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.

       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 number sign (#) 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 quotation marks (" ") 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.

       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 rule 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 executes the following 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 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

	       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.  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.

Options
       -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.  The compiler will act as if the file contained a link line of the form:
	    Link     timezonelocaltime

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

Files
       Standard directory used for created files

See Also
       ctime(3), tzfile(5), zdump(8)

																	    zic(8)