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zic(8)
NAME
zic - Time zone compiler
SYNOPSIS
/usr/bin/zic [-v] [-d directory] [-l localtime] [-p posixrules] [-l
leapsecondfilename] [-s] [-y commandname] [filename...]
OPTIONS
-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. The zic compiler 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. The zic compiler will act as if the input
contained 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(3) 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).
DESCRIPTION
The zic compiler 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.
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 # (octothorpe) character in the input
introduces a comment which extends to the end of the line on which the #
character appears on. White space characters and # characters may be
enclosed in double quotation marks (" ") if they are 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 with a representable time
value. The word maximum (or an abbreviation) means the maximum year
with a representable time value. 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 abbreviation) 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 following command to check the
type of a year:
yearistype year type
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. Recognized 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
Any of these forms may be followed by the letter w if the given time is
local wall clock time, the letter s if the given time is local standard
time, or the letter 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 GMT 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 GMT.
RULES/SAVE
The name of the rule(s) that apply in the time zone or, alternately, 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 / (forward slash) separates standard
and daylight abbreviations.
UNTIL
The time at which the GMT 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 generated from the given GMT
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 missing 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
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 describe 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 GMT 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
compiled file is correct.
FILES
/etc/zoneinfo
Standard directory used for created files
/usr/sbin/yearistype
Default script used to determine type of year
SEE ALSO
Commands: zdump(8)
Functions: ctime(3)
Files: tzfile(4)
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Index for
Section 8 |
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Alphabetical
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Top of
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