1 .\" This page is in the public domain
3 .TH ZIC 8 2007-05-18 "" "Linux System Administration"
5 zic \- timezone compiler
36 \\$3\*(lq\\$1\*(rq\\$2
39 reads text from the file(s) named on the command line
40 and creates the time conversion information files specified in this input.
45 the standard input is read.
47 These options are available:
50 Create time conversion information files in the named directory rather than
51 in the standard directory named below.
54 Use the given timezone as local time.
56 will act as if the input contained a link line of the form
59 Link \fItimezone\fP localtime
62 Use the given timezone's rules when handling POSIX-format
63 timezone environment variables.
65 will act as if the input contained a link line of the form
68 Link \fItimezone\fP posixrules
70 .BI "\-L " leapsecondfilename
71 Read leap second information from the file with the given name.
72 If this option is not used,
73 no leap second information appears in output files.
76 Complain if a year that appears in a data file is outside the range
77 of years representable by
82 Limit time values stored in output files to values that are the same
83 whether they're taken to be signed or unsigned.
84 You can use this option to generate SVVS-compatible files.
91 when checking year types (see below).
93 Input lines are made up of fields.
94 Fields are separated from one another by any number of white space characters.
95 Leading and trailing white space on input lines is ignored.
96 An unquoted sharp character (#) in the input introduces a comment which extends
97 to the end of the line the sharp character appears on.
98 White space characters and sharp characters may be enclosed in double quotes
99 (") if they're to be used as part of a field.
100 Any line that is blank (after comment stripping) is ignored.
101 Nonblank lines are expected to be of one of three types:
102 rule lines, zone lines, and link lines.
104 A rule line has the form
107 .ta \w'Rule\0\0'u +\w'NAME\0\0'u +\w'FROM\0\0'u +\w'1973\0\0'u +\w'TYPE\0\0'u +\w'Apr\0\0'u +\w'lastSun\0\0'u +\w'2:00\0\0'u +\w'SAVE\0\0'u
109 Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S
114 Rule US 1967 1973 \- Apr lastSun 2:00 1:00 D
117 The fields that make up a rule line are:
120 Gives the (arbitrary) name of the set of rules this rule is part of.
123 Gives the first year in which the rule applies.
124 Any integer year can be supplied; the Gregorian calendar is assumed.
127 (or an abbreviation) means the minimum year representable as an integer.
130 (or an abbreviation) means the maximum year representable as an integer.
131 Rules can describe times that are not representable as time values,
132 with the unrepresentable times ignored; this allows rules to be portable
133 among hosts with differing time value types.
136 Gives the final year in which the rule applies.
145 may be used to repeat the value of the
150 Gives the type of year in which the rule applies.
155 then the rule applies in all years between
162 is something else, then
166 \fByearistype\fP \fIyear\fP \fItype\fP
168 to check the type of a year:
169 an exit status of zero is taken to mean that the year is of the given type;
170 an exit status of one is taken to mean that the year is not of the given type.
173 Names the month in which the rule takes effect.
174 Month names may be abbreviated.
177 Gives the day on which the rule takes effect.
178 Recognized forms include:
183 5 the fifth of the month
184 lastSun the last Sunday in the month
185 lastMon the last Monday in the month
186 Sun>=8 first Sunday on or after the eighth
187 Sun<=25 last Sunday on or before the 25th
191 Names of days of the week may be abbreviated or spelled out in full.
192 Note that there must be no spaces within the
197 Gives the time of day at which the rule takes effect.
198 Recognized forms include:
204 2:00 time in hours and minutes
205 15:00 24-hour format time (for times after noon)
206 1:28:14 time in hours, minutes, and seconds
211 where hour 0 is midnight at the start of the day,
212 and hour 24 is midnight at the end of the day.
213 Any of these forms may be followed by the letter
215 if the given time is local
219 if the given time is local
227 if the given time is universal time;
228 in the absence of an indicator,
229 wall clock time is assumed.
232 Gives the amount of time to be added to local standard time when the rule is in
234 This field has the same format as the
237 (although, of course, the
241 suffixes are not used).
254 of timezone abbreviations to be used when this rule is in effect.
257 the variable part is null.
259 A zone line has the form
263 .ta \w'Zone\0\0'u +\w'Australia/Adelaide\0\0'u +\w'UTCOFF\0\0'u +\w'RULES/SAVE\0\0'u +\w'FORMAT\0\0'u
264 Zone NAME UTCOFF RULES/SAVE FORMAT [UNTIL]
269 Zone Australia/Adelaide 9:30 Aus CST 1971 Oct 31 2:00
272 The fields that make up a zone line are:
275 The name of the timezone.
276 This is the name used in creating the time conversion information file for the
280 The amount of time to add to UTC to get standard time in this zone.
281 This field has the same format as the
285 fields of rule lines;
286 begin the field with a minus sign if time must be subtracted from UTC.
289 The name of the rule(s) that apply in the timezone or,
290 alternately, an amount of time to add to local standard time.
293 then standard time always applies in the timezone.
296 The format for timezone abbreviations in this timezone.
297 The pair of characters
299 is used to show where the
301 of the timezone abbreviation goes.
304 separates standard and daylight abbreviations.
307 The time at which the UTC offset or the rule(s) change for a location.
308 It is specified as a year, a month, a day, and a time of day.
309 If this is specified,
310 the timezone information is generated from the given UTC offset
311 and rule change until the time specified.
312 The month, day, and time of day have the same format as the IN, ON, and AT
313 columns of a rule; trailing columns can be omitted, and default to the
314 earliest possible value for the missing columns.
316 The next line must be a
318 line; this has the same form as a zone line except that the
321 and the name are omitted, as the continuation line will
322 place information starting at the time specified as the
324 field in the previous line in the file used by the previous line.
325 Continuation lines may contain an
327 field, just as zone lines do, indicating that the next line is a further
330 A link line has the form
334 .ta \w'Link\0\0'u +\w'Europe/Istanbul\0\0'u
335 Link LINK-FROM LINK-TO
340 Link Europe/Istanbul Asia/Istanbul
345 field should appear as the
347 field in some zone line;
350 field is used as an alternate name for that zone.
352 Except for continuation lines,
353 lines may appear in any order in the input.
355 Lines in the file that describes leap seconds have the following form:
358 .ta \w'Leap\0\0'u +\w'YEAR\0\0'u +\w'MONTH\0\0'u +\w'DAY\0\0'u +\w'HH:MM:SS\0\0'u +\w'CORR\0\0'u
360 Leap YEAR MONTH DAY HH:MM:SS CORR R/S
365 Leap 1974 Dec 31 23:59:60 + S
374 fields tell when the leap second happened.
380 if a second was added
383 if a second was skipped.
384 .\" There's no need to document the following, since it's impossible for more
385 .\" than one leap second to be inserted or deleted at a time.
386 .\" The C Standard is in error in suggesting the possibility.
387 .\" See Terry J Quinn, The BIPM and the accurate measure of time,
388 .\" Proc IEEE 79, 7 (July 1991), 894-905.
391 .\" if two seconds were added
394 .\" if two seconds were skipped.
398 should be (an abbreviation of)
400 if the leap second time given by the other fields should be interpreted as UTC
404 if the leap second time given by the other fields should be interpreted as
405 local wall clock time.
407 /usr/local/etc/zoneinfo standard directory used for created files
409 For areas with more than two types of local time,
410 you may need to use local standard time in the
412 field of the earliest transition time's rule to ensure that
413 the earliest transition time recorded in the compiled file is correct.