zic(1M) zic(1M)
NAME
zic - time zone compiler
SYNOPSIS
zic [ -v ] [ -d directory ] [ -l localtime ] [ filename ... ]
DESCRIPTION
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.
Input lines are made up of fields. Fields are separated by any
number of white space characters. Leading and trailing white space
on input lines is ignored. A pound sign (#) in the input introduces
a comment which extends to the end of the line the pound sign appears
on. White space characters and pound signs 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 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
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.
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 uspres, the rule applies in U.S.
Presidential election years; if TYPE is nonpres, the rule
applies in years other than U.S. Presidential election years.
If TYPE is something else, then zic executes the command
yearistype year type
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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: 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 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
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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 GMTOFF RULES/SAVE FORMAT
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. 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 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
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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.
OPTIONS
-v Complain if a year that appears in a data file is outside the
range of years representable by system time values (0:00:00 AM
GMT, January 1, 1970, to 3:14:07 AM GMT, January 19, 2038).
-d directory
Create time conversion information files in the directory
directory rather than in the standard directory
/usr/lib/locale/TZ.
-l timezone
Use the time zone timezone as local time. zic will act as if
the file contained a link line of the form
Link timezone localtime
FILES
/usr/lib/locale/TZ
standard directory used for created files
SEE ALSO
time(1), ctime(3)
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.
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