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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  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 repre‐
              sentable 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 abbrevia‐
               tion) 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 maxi‐
               mum (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 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                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.  Alter‐
             nately, 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 speci‐
             fied 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 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 earli‐
             est 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 pre‐
             vious 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  con‐
             tinuation.

       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 transi‐
       tion time recorded in the compiled file is correct.

SEE ALSO
       tzfile(5), zdump(8)

COLOPHON
       This page is part of release 4.04 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 http://www.kernel.org/doc/man-pages/.

                                            2010-02-25                                     ZIC(8)

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