1ZIC(8)                      System Manager's Manual                     ZIC(8)
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NAME

6       zic - time zone compiler
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SYNOPSIS

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

13       Zic reads text from the file(s) named on the command line  and  creates
14       the  time  conversion  information files specified in this input.  If a
15       filename is -, the standard input is read.
16
17       These options are available:
18
19       -d directory
20              Create time conversion information files in the named  directory
21              rather than in the standard directory named below.
22
23       -l timezone
24              Use  the  given time zone as local time.  Zic will act as if the
25              input contained a link line of the form
26
27                   Link timezone       localtime
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29       -p timezone
30              Use the given time zone's rules when handling POSIX-format  time
31              zone  environment  variables.  Zic will act as if the input con‐
32              tained a link line of the form
33
34                   Link timezone       posixrules
35
36       -L leapsecondfilename
37              Read leap second information from the file with the given  name.
38              If  this  option is not used, no leap second information appears
39              in output files.
40
41       -v     Complain if a year that appears in a data file  is  outside  the
42              range of years representable by time(2) values.
43
44       -s     Limit  time values stored in output files to values that are the
45              same whether they're taken to be signed or  unsigned.   You  can
46              use this option to generate SVVS-compatible files.
47
48       -y command
49              Use  the given command rather than yearistype when checking year
50              types (see below).
51
52       Input lines are made up of  fields.   Fields  are  separated  from  one
53       another  by any number of white space characters.  Leading and trailing
54       white space on input lines is ignored.  An unquoted sharp character (#)
55       in  the input introduces a comment which extends to the end of the line
56       the sharp character appears on.  White space characters and sharp char‐
57       acters  may  be  enclosed in double quotes (") if they're to be used as
58       part of a field.  Any line that is blank (after comment  stripping)  is
59       ignored.   Non-blank  lines  are  expected to be of one of three types:
60       rule lines, zone lines, and link lines.
61
62       A rule line has the form
63
64            Rule  NAME  FROM  TO    TYPE  IN   ON       AT    SAVE  LETTER/S
65
66       For example:
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68            Rule  US    1967  1973  -     Apr  lastSun  2:00  1:00  D
69
70       The fields that make up a rule line are:
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72       NAME    Gives the (arbitrary) name of the set of  rules  this  rule  is
73               part of.
74
75       FROM    Gives  the  first  year in which the rule applies.  Any integer
76               year can be supplied; the Gregorian calendar is  assumed.   The
77               word minimum (or an abbreviation) means the minimum year repre‐
78               sentable as an integer.  The word maximum (or an  abbreviation)
79               means  the maximum year representable as an integer.  Rules can
80               describe times that are not representable as time values,  with
81               the unrepresentable times ignored; this allows rules to be por‐
82               table among hosts with differing time value types.
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84       TO      Gives the final year in which the rule applies.  In addition to
85               minimum  and maximum (as above), the word only (or an abbrevia‐
86               tion) may be used to repeat the value of the FROM field.
87
88       TYPE    Gives the type of year in which the rule applies.  If TYPE is -
89               then  the  rule applies in all years between FROM and TO inclu‐
90               sive.  If TYPE is something else, then zic executes the command
91                    yearistype year type
92               to check the type of a year: an exit status of zero is taken to
93               mean  that the year is of the given type; an exit status of one
94               is taken to mean that the year is not of the given type.
95
96       IN      Names the month in which the rule takes  effect.   Month  names
97               may be abbreviated.
98
99       ON      Gives the day on which the rule takes effect.  Recognized forms
100               include:
101
102                    5        the fifth of the month
103                    lastSun  the last Sunday in the month
104                    lastMon  the last Monday in the month
105                    Sun>=8   first Sunday on or after the eighth
106                    Sun<=25  last Sunday on or before the 25th
107
108               Names of days of the week may be abbreviated or spelled out  in
109               full.  Note that there must be no spaces within the ON field.
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111       AT      Gives  the  time of day at which the rule takes effect.  Recog‐
112               nized forms include:
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114                    2        time in hours
115                    2:00     time in hours and minutes
116                    15:00    24-hour format time (for times after noon)
117                    1:28:14  time in hours, minutes, and seconds
118                    -        equivalent to 0
119
120               where hour 0 is midnight at the start of the day, and  hour  24
121               is  midnight  at the end of the day.  Any of these forms may be
122               followed by the letter w if  the  given  time  is  local  "wall
123               clock" time, s if the given time is local "standard" time, or u
124               (or g or z) if the given time is universal time; in the absence
125               of an indicator, wall clock time is assumed.
126
127       SAVE    Gives  the  amount  of  time to be added to local standard time
128               when the rule is in effect.  This field has the same format  as
129               the AT field (although, of course, the w and s suffixes are not
130               used).
131
132       LETTER/S
133               Gives the "variable part" (for example, the "S" or "D" in "EST"
134               or  "EDT") of time zone abbreviations to be used when this rule
135               is in effect.  If this field is -, the variable part is null.
136
137       A zone line has the form
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139            Zone  NAME                GMTOFF  RULES/SAVE  FORMAT  [UNTIL]
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141       For example:
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143            Zone  Australia/Adelaide  9:30    Aus         CST     1971 Oct 31 2:00
144
145       The fields that make up a zone line are:
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147       NAME  The name of the time zone.  This is the name used in creating the
148             time conversion information file for the zone.
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150       GMTOFF
151             The  amount  of  time  to add to UTC to get standard time in this
152             zone.  This field has the same format as the AT and  SAVE  fields
153             of  rule lines; begin the field with a minus sign if time must be
154             subtracted from UTC.
155
156       RULES/SAVE
157             The name of the rule(s) that apply in the time  zone  or,  alter‐
158             nately, an amount of time to add to local standard time.  If this
159             field is - then standard time always applies in the time zone.
160
161       FORMAT
162             The format for time zone abbreviations in this  time  zone.   The
163             pair  of  characters %s is used to show where the "variable part"
164             of the time zone abbreviation goes.   Alternately,  a  slash  (/)
165             separates standard and daylight abbreviations.
166
167       UNTIL The  time  at  which  the  UTC offset or the rule(s) change for a
168             location.  It is specified as a year, a month, a day, and a  time
169             of  day.  If this is specified, the time zone information is gen‐
170             erated from the given UTC offset and rule change until  the  time
171             specified.   The month, day, and time of day have the same format
172             as the IN, ON, and AT columns of a rule; trailing columns can  be
173             omitted, and default to the earliest possible value for the miss‐
174             ing columns.
175
176             The next line must be a "continuation" line; this  has  the  same
177             form  as  a  zone line except that the string "Zone" and the name
178             are omitted, as the  continuation  line  will  place  information
179             starting at the time specified as the UNTIL field in the previous
180             line in the file used by the previous line.   Continuation  lines
181             may  contain  an  UNTIL  field, just as zone lines do, indicating
182             that the next line is a further continuation.
183
184       A link line has the form
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186            Link  LINK-FROM        LINK-TO
187
188       For example:
189
190            Link  Europe/Istanbul  Asia/Istanbul
191
192       The LINK-FROM field should appear as the NAME field in some zone  line;
193       the LINK-TO field is used as an alternate name for that zone.
194
195       Except  for  continuation  lines,  lines may appear in any order in the
196       input.
197
198       Lines in the file that describes leap seconds have the following form:
199
200            Leap  YEAR  MONTH  DAY  HH:MM:SS  CORR  R/S
201
202       For example:
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204            Leap  1974  Dec    31   23:59:60  +     S
205
206       The YEAR, MONTH, DAY, and HH:MM:SS fields tell  when  the  leap  second
207       happened.  The CORR field should be "+" if a second was added or "-" if
208       a second was skipped.  The R/S field should  be  (an  abbreviation  of)
209       "Stationary"  if  the leap second time given by the other fields should
210       be interpreted as UTC or (an abbreviation of)  "Rolling"  if  the  leap
211       second  time  given  by the other fields should be interpreted as local
212       wall clock time.
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NOTE

215       For areas with more than two types of local time, you may need  to  use
216       local  standard  time in the AT field of the earliest transition time's
217       rule to ensure that the earliest transition time recorded in  the  com‐
218       piled file is correct.
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FILE

221       /usr/local/etc/zoneinfo standard directory used for created files
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SEE ALSO

224       tzfile(5), zdump(8)
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