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 timezone as local time.
Zic
will act as if the input contained a link line of the form
Linktimezonelocaltime
-p timezone
Use the given timezone's rules when handling POSIX-format
timezone environment variables.
Zic
will act as if the input contained a link line of the form
Linktimezoneposixrules
-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 characters 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 representable 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 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 command
yearistypeyeartype
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.
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
- 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
time,
s
if the given time is local
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
(for example, the
or
in
or
of timezone 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 AusCST1971 Oct 31 2:00
The fields that make up a zone line are:
NAME
The name of the timezone.
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 timezone or,
alternately, an amount of time to add to local standard time.
If this field is
-
then standard time always applies in the timezone.
FORMAT
The format for timezone abbreviations in this timezone.
The pair of characters
%s
is used to show where the
of the timezone 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 timezone information is generated 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 missing columns.
The next line must be a
line; this has the same form as a zone line except that the
string
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/IstanbulAsia/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)
if the leap second time given by the other fields should be interpreted as UTC
or
(an abbreviation of)
if the leap second time given by the other fields should be interpreted as
local wall clock time.
FILES
/usr/local/etc/zoneinfostandard directory used for created files
NOTES
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.
This page is part of release 3.14 of the Linux
man-pages
project.
A description of the project,
and information about reporting bugs,
can be found at
http://www.kernel.org/doc/man-pages/.
