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

NAME
     zic - time zone compiler

SYNOPSIS
     zic [-sv] [-d directory] [-L leapsecondfilename] [-l timezone]
         [-p timezone] [-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 di-
                   rectory rather than in the standard directory named below.

     -L leapsecondfilename
                   Read leap second information from the file with the given
                   name.  If this option is not used, no leap second informa-
                   tion appears in output files.

     -l timezone   Use the given time zone 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 time zone's rules when handling POSIX-format
                   time zone environment variables.  zic will act as if the
                   input contained a link line of the form

                         Link timezone       posixrules

     -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.

     -v            Complain if a year that appears in a data file is outside
                   the range of years representable by time(3) values.  Also
                   complain if a time of 24:00 (which cannot be handled by
                   pre-1998 versions of zic) appears in the input.

     -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 whitespace characters.  Leading and trailing whitespace
     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 char-
     acter appears on.  White space characters and sharp characters may be en-
     closed 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  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
               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 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 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/Adelaide  9:30    Aus         CST     1971 Oct 31 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 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 time zone or, alter-
             nately, 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.  Alternately, a slash (/)
             separates standard and daylight abbreviations.

     UNTIL   The time at which the UTC offset or the rule(s) change for a lo-
             cation.  It is specified as a year, a month, a day, and a time of
             day.  If this is specified, the time zone information is generat-
             ed from the given UTC offset and rule change until the time spec-
             ified.  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 in-
     put.

     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 hap-
     pened.  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.

NOTES
     For areas with more than two types of local time, you may need to use lo-
     cal 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
     /etc/localtime       link to local time zone
     /usr/share/zoneinfo  standard directory used for created files

SEE ALSO
     ctime(3), tzfile(5), zdump(8)

OpenBSD 3.6                      May 23, 1999                                4