zic



ZIC(8)                                                                  ZIC(8)




NAME

       zic - time zone 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 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 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.   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 inclu-
               sive.  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
             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  gen-
             erated  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.


NOTE

       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.


FILE

       /usr/local/etc/zoneinfo standard directory used for created files


SEE ALSO

       newctime(3), tzfile(5), zdump(8)



                                                                        ZIC(8)

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