zic(8)zic(8)Namezic - time zone compiler
Syntaxzic [ -d directory ] [ -l localtime ] [ -v ] [ filename ... ]
Description
The 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 number sign (#) in
the input introduces a comment which extends to the end of the line the
sharp character appears on. White space characters and sharp charac‐
ters 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 strip‐
ping) 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 USA 1969 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. The word mini‐
mum (or an abbreviation) means the minimum year with a repre‐
sentable time value. The word maximum (or an abbreviation)
means the maximum year with a representable time value.
TO Gives the final year in which the rule applies. In addition to
minimum and maximum (as above), the word only (or an abbrevia‐
tion) 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 inclu‐
sive; if TYPE is `uspres', the rule applies in U.S. Presiden‐
tial election years; if TYPE is `nonpres', the rule applies in
years other than U.S. Presidential election years. If TYPE is
something else, then executes the following command:
yearistype year type
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. Recog‐
nized 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 or s if the given time is local
`standard' time; in the absence of w or s, `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/South-west 9:30 Aus CST 1987 Mar 15 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, alter‐
nately, 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.
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 gen‐
erated from the given GMT offset and rule change until the time
specified.
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 continuation.
A link line has the form
"Link LINK-FROM LINK-TO"
For example:
Link US/Eastern EST5EDT
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. 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.
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 compiler will act as
if the file contained a link line of the form:
Link timezonelocaltime
-v Complain if a year that appears in a data file is outside the
range of years representable by values.
Files
Standard directory used for created files
See Alsoctime(3), tzfile(5), zdump(8)zic(8)
