ZIC(8)			  Linux System Administration			ZIC(8)



NAME
       zic - timezone compiler

SYNOPSIS
       zic  [  -v  ]  [ -d directory ] [ -l localtime ] [ -p posixrules ] [ -L
       leapsecondfilename ] [ -s ] [ -y command ] [ 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  timezone as local time.	Zic will act as if the
	      input contained a link line of the form

		   Link timezone       localtime

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

		   Link timezone       posixrules

       -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.

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

       -s     Limit  time values stored in output files to values that are the
	      same whether they're 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 char-
       acters  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.	 Nonblank 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  US	1967  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.  Any integer
	       year can be supplied; the Gregorian calendar is	assumed.   The
	       word minimum (or an abbreviation) means the minimum year repre-
	       sentable as an integer.	The word maximum (or an	 abbreviation)
	       means  the maximum year representable as an integer.  Rules can
	       describe times that are not representable as time values,  with
	       the unrepresentable times ignored; this allows rules to be por-
	       table among hosts with differing time value types.

       TO      Gives the final year in which the rule applies.	In addition to
	       minimum	and maximum (as above), the word only (or an abbrevia-
	       tion) 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 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  effect.	Recog-
	       nized 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
		    -	     equivalent to 0

	       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 indicator, 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 timezone 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		      UTCOFF  RULES/SAVE  FORMAT  [UNTIL]

       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 timezone.	 This is the name used in creating the
	     time conversion information file for the zone.

       UTCOFF
	     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 timezone or, alter-
	     nately, an amount of time to add to local standard time.  If this
	     field is -, then standard time always applies in the timezone.

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

       UNTIL 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 timezone information is gener-
	     ated  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 columns of a rule; trailing columns can be
	     omitted, and default to the earliest possible value for the miss-
	     ing columns.

	     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  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
       happened.  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.

FILES
       /usr/local/etc/zoneinfo
	      Standard directory used for created files.

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 com-
       piled file is correct.

SEE ALSO
       tzfile(5), zdump(8)

COLOPHON
       This page is part of release 4.10 of the Linux  man-pages  project.   A
       description  of	the project, information about reporting bugs, and the
       latest	 version    of	  this	  page,	   can	   be	  found	    at
       https://www.kernel.org/doc/man-pages/.



				  2010-02-25				ZIC(8)