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NAME

       zic - timezone compiler

SYNOPSIS

       zic [-v] [-d directory] [-l localtime] [-p posixrules]
           [-L leapsecondfilename] [-s] [-y command] [filename...]

DESCRIPTION

       The zic program 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 -, 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 timezone environment
              variables.  zic will act as if the input contained 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 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.  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  representable  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 portable 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 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 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.  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
       -        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, alternately, 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  generated 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 missing 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 compiled file is correct.

SEE ALSO

       tzfile(5), zdump(8)

COLOPHON

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                                            2010-02-25                                     ZIC(8)