1ZIC(8) Linux System Administration ZIC(8)
2
6 zic - timezone compiler
7
9 zic [-v] [-d directory] [-l localtime] [-p posixrules]
10 [-L leapsecondfilename] [-s] [-y command] [filename...]
11
13 The zic program reads text from the file(s) named on the command line
14 and creates the time conversion information files specified in this
15 input. If a filename is -, standard input is read.
16 These options are available:
18 -d directory
20 Create time conversion information files in the named directory
21 rather than in the standard directory named below.
22 -l timezone
24 Use the given timezone as local time. zic will act as if the
25 input contained a link line of the form
26 Link timezone localtime
28 -p timezone
30 Use the given timezone'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 Link timezone posixrules
35 -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 -v Complain if a year that appears in a data file is outside the
42 range of years representable by time(2) values.
43 -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 -y command
49 Use the given command rather than yearistype when checking year
50 types (see below).
51 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. Nonblank lines are expected to be of one of three types: rule
60 lines, zone lines, and link lines.
61 A rule line has the form
63 Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S
65 For example:
67 Rule US 1967 1973 - Apr lastSun 2:00 1:00 D
69 The fields that make up a rule line are:
71 NAME Gives the (arbitrary) name of the set of rules this rule is
73 part of.
74 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.
83 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 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
90 inclusive. If TYPE is something else, then zic executes the
91 command
92 yearistype year type
93 to check the type of a year: an exit status of zero is taken to
94 mean that the year is of the given type; an exit status of one
95 is taken to mean that the year is not of the given type.
96 IN Names the month in which the rule takes effect. Month names
98 may be abbreviated.
99 ON Gives the day on which the rule takes effect. Recognized forms
101 include:
102 5 the fifth of the month
104 lastSun the last Sunday in the month
105 lastMon the last Monday in the month
106 Sun>=8 first Sunday on or after the eighth
107 Sun<=25 last Sunday on or before the 25th
108 Names of days of the week may be abbreviated or spelled out in full.
110 Note that there must be no spaces within the ON field.
111 AT Gives the time of day at which the rule takes effect. Recog‐
113 nized forms include:
114 2 time in hours
116 2:00 time in hours and minutes
117 15:00 24-hour format time (for times after noon)
118 1:28:14 time in hours, minutes, and seconds
119 - equivalent to 0
120 where hour 0 is midnight at the start of the day, and hour 24 is mid‐
122 night at the end of the day. Any of these forms may be followed by the
123 letter w if the given time is local "wall clock" time, s if the given
124 time is local "standard" time, or u (or g or z) if the given time is
125 universal time; in the absence of an indicator, wall clock time is
126 assumed.
127 SAVE Gives the amount of time to be added to local standard time when
129 the rule is in effect. This field has the same format as the AT
130 field (although, of course, the w and s suffixes are not used).
131 LETTER/S
133 Gives the "variable part" (for example, the "S" or "D" in "EST"
134 or "EDT") of timezone abbreviations to be used when this rule is
135 in effect. If this field is -, the variable part is null.
136 A zone line has the form
138 Zone NAME UTCOFF RULES/SAVE FORMAT [UNTIL]
140 For example:
142 Zone Australia/Adelaide 9:30 Aus CST 1971 Oct 31 2:00
144 The fields that make up a zone line are:
146 NAME The name of the timezone. This is the name used in creating the
148 time conversion information file for the zone.
149 UTCOFF
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 RULES/SAVE
157 The name of the rule(s) that apply in the timezone 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 timezone.
160 FORMAT
162 The format for timezone abbreviations in this timezone. The pair
163 of characters %s is used to show where the "variable part" of the
164 timezone abbreviation goes. Alternately, a slash (/) separates
165 standard and daylight abbreviations.
166 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 timezone information is gener‐
170 ated 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 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 A link line has the form
185 Link LINK-FROM LINK-TO
187 For example:
189 Link Europe/Istanbul Asia/Istanbul
191 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 Except for continuation lines, lines may appear in any order in the
196 input.
197 Lines in the file that describes leap seconds have the following form:
199 Leap YEAR MONTH DAY HH:MM:SS CORR R/S
201 For example:
203 Leap 1974 Dec 31 23:59:60 + S
205 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.
213
215 /usr/local/etc/zoneinfo
216 Standard directory used for created files.
217
219 For areas with more than two types of local time, you may need to use
220 local standard time in the AT field of the earliest transition time's
221 rule to ensure that the earliest transition time recorded in the com‐
222 piled file is correct.
223
225 tzfile(5), zdump(8)
226
228 This page is part of release 4.16 of the Linux man-pages project. A
229 description of the project, information about reporting bugs, and the
230 latest version of this page, can be found at
231 https://www.kernel.org/doc/man-pages/.
232 2010-02-25 ZIC(8)